Obstruction detection system and method for detecting an obstruction

Abstract

An obstruction detection system (100) comprising a detector (130) comprising a sensor module (114). The obstruction detection system (100) is configured to: record commissioning sensor data, using the sensor module (114), during a commissioning phase in which the sensor module (114) detects electromagnetic radiation emitted by an emitter (140); determine a nominal pattern of electromagnetic radiation that is emitted by the emitter (140) and detected by the sensor module (114) during the commissioning phase, using the commissioning sensor data; compare subsequently detected electromagnetic radiation, that is emitted by the emitter (140) and detected by the sensor module (114) during an operating phase, to the nominal pattern; and generate an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

Description

OBSTRUCTION DETECTION SYSTEM AND METHOD FOR DETECTING ANOBSTRUCTIONTECHNICAL FIELD

[0001] The present disclosure relates to obstruction detection systems, and more particularly to an obstruction detection system that uses electromagnetic radiation to detect obstructions in industrial settings.BACKGROUND

[0002] Industrial machinery and manufacturing processes often involve moving parts that can pose significant risks to operators and nearby personnel, as well as operational risks to other nearby equipment. Conventional control systems typically rely on physical barriers or basic light curtains to prevent access to dangerous areas. However, these traditional approaches can be inflexible, difficult to configure, and may not provide optimal protection in dynamic industrial environments.

[0003] Advancements in sensing technologies and image processing have enabled the development of more sophisticated obstruction detection systems. These systems aim to enhance workplace safety and decrease operational disruptions by detecting potential obstructions or unauthorised entry or equipment movement into hazardous zones. However, challenges remain in achieving reliable detection across varied industrial settings, accommodating equipment movement, and minimising false alarms.

[0004] ft is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.SUMMARY

[0005] In some embodiments, there is provided an obstruction detection system comprising: a detector comprising a sensor module that is configured to enable detection of electromagnetic radiation that is: emitted by an emitter; and incident to a sensor of the sensor module; wherein the obstruction detection system is configured to perform operations comprising: recording commissioning sensor data, using the sensor module, during a commissioning phase in which the sensor module detects electromagnetic radiation emitted by the emitter; determining a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; comparing subsequently detected electromagnetic radiation to the nominal pattern; and generating an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

[0006] In some embodiments, recording the commissioning sensor data comprises: sampling the sensor, during the commissioning phase, to determine the commissioning sensor data; and storing, in the memory, the commissioning sensor data.

[0007] In some embodiments, determining the nominal pattern comprises identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

[0008] In some embodiments, comparing subsequently detected electromagnetic radiation to the nominal pattern comprises: identifying one or more zones of the sensor at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

[0009] In some embodiments, comparing the one or more zones to the one or more nominal zones of the nominal pattern comprises determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

[0010] In some embodiments, the obstruction indication output is generated when the difference is greater than a difference threshold.

[0011] In some embodiments, the difference threshold is a surface area overlap threshold.

[0012] In some embodiments, the obstruction indication output is configured to change an operating parameter of a piece of industrial equipment.

[0013] In some embodiments, the obstruction detection system further comprises at least one of: an optical fdter that is configured to filter electromagnetic radiation that is incident to the sensor based on a wavelength of the electromagnetic radiation; and a polariser that is configured to enable electromagnetic radiation with a specific polarisation to pass through while blocking electromagnetic radiation with other polarisations.

[0014] In some embodiments, the operations further comprise adjusting the nominal pattern based on environmental conditions.

[0015] In some embodiments, the obstruction detection system further comprises the emitter.

[0016] In some embodiments, the emitter comprises a plurality of emission units, each being configured to emit electromagnetic radiation at the detector.

[0017] In some embodiments, the detector comprises a plurality of sensor modules; and each emission unit is configured to emit electromagnetic radiation at a respective sensor module.

[0018] In some embodiments, the operations further comprise: identifying one or more regions of the detector corresponding to an expected movement path of equipment during normal operation of the equipment; designating the identified regions as dynamic exclusion zones of the detector; and selectively disregarding electromagnetic radiation detected within the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected equipment movement.

[0019] In some embodiments, there is provided an obstruction detection system comprising: a detector comprising a plurality of sensor modules, each sensor module being configured to enable detection of electromagnetic radiation that is: emitted by an emitter; and incident to a sensor of the sensor module; wherein the obstruction detection system is configured to perform operations comprising: recording commissioning sensor data for each sensor module, using the respective sensor module, during acommissioning phase in which the sensor modules detect electromagnetic radiation emitted by the emitter; determining, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; comparing electromagnetic radiation that is subsequently detected by each of the sensor modules to the nominal pattern of the respective sensor module; and generating an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing the nominal pattern of that sensor module.

[0020] In some embodiments, there is provided a method comprising: recording commissioning sensor data, using a sensor module, during a commissioning phase in which the sensor module detects electromagnetic radiation emitted by an emitter; determining a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; comparing subsequently detected electromagnetic radiation to the nominal pattern; and generating an obstmction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

[0021] In some embodiments, recording the commissioning sensor data comprises: sampling a sensor of the sensor module, during the commissioning phase, to determine the commissioning sensor data; and storing, in the memory, the commissioning sensor data.

[0022] In some embodiments, determining the nominal pattern comprises identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

[0023] In some embodiments, comparing subsequently detected electromagnetic radiation to the nominal pattern comprises: identifying one or more zones of the sensor at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

[0024] In some embodiments, comparing the one or more zones to the one or more nominal zones of the nominal pattern comprises determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

[0025] In some embodiments, the obstruction indication output is generated when the difference is greater than a difference threshold.

[0026] In some embodiments, the difference threshold is a surface area overlap threshold.

[0027] In some embodiments, the obstruction indication output is configured to change an operating parameter of a piece of industrial equipment.

[0028] In some embodiments, the method further comprises filtering electromagnetic radiation that is incident to the sensor using an optical filter.

[0029] In some embodiments, the method further comprises adjusting the nominal pattern based on environmental conditions.

[0030] In some embodiments, the method further comprises identifying one or more regions of the sensor corresponding to an expected movement path of equipment during normal operation of theequipment; designating the identified regions as dynamic exclusion zones of the sensor module; and selectively disregarding electromagnetic radiation detected within the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected equipment movement.

[0031] In some embodiments, there is provided a method comprising: recording commissioning sensor data for each of a plurality of sensor modules, using the respective sensor module, during a commissioning phase in which the sensor modules detect electromagnetic radiation emitted by the emitter; determining, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; comparing electromagnetic radiation that is subsequently detected by each of the sensor modules to the nominal pattern of the respective sensor module; and generating an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing the nominal pattern of that sensor module.

[0032] In some embodiments of the present disclosure, there is provided an obstruction detection system. The obstruction detection system may comprise a detector comprising a sensor module, the sensor module being configured to detect electromagnetic radiation that is emitted by an emitter and incident to a sensor of the sensor module. The obstruction detection system may be configured to: record commissioning sensor data, using the sensor module, during a commissioning phase in which the sensor module detects electromagnetic radiation emitted by the emitter; determine a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; compare subsequently detected electromagnetic radiation, that is emitted by the emitter and detected by the sensor module during an operating phase, to the nominal pattern; and generate an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

[0033] Recording the commissioning sensor data may comprise: sampling the sensor, during the commissioning phase, to determine the commissioning sensor data that indicates at least one characteristic of electromagnetic radiation incident to the sensor during a period of the commissioning phase; and storing, in a memory of the obstruction detection system, the commissioning sensor data.

[0034] The at least one characteristic may comprise at least one of: a spatial distribution of electromagnetic radiation detected by the sensor; an intensity of electromagnetic radiation detected by the sensor; a wavelength of electromagnetic radiation detected by the sensor; a polarisation of electromagnetic radiation detected by the sensor; a timing of detection of electromagnetic radiation by the sensor; and x-y coordinates of pixels of the sensor at which electromagnetic radiation is detected.

[0035] Determining the nominal pattern may comprise identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

[0036] Determining the nominal pattern may comprise: identifying areas of peak intensity on the sensor where electromagnetic radiation emitted by the emitter is detected above a threshold intensity; and classifying the identified areas of peak intensity as the one or more nominal zones.

[0037] Determining the nominal pattern may comprise: establishing an intensity threshold; classifying pixels detecting electromagnetic radiation emitted by the emitter with intensity above the intensity threshold as part of the one or more nominal zones; and storing x-y coordinates of the classified pixels in a memory of the obstruction detection system.

[0038] Determining the nominal pattern may comprise: determining a maximum detected intensity of electromagnetic radiation emitted by the emitter and detected by the sensor; identifying regions of the sensor where intensity exceeds a percentage of the maximum detected intensity; and classifying the identified regions as the one or more nominal zones.

[0039] Determining the nominal pattern may comprise: applying edge detection algorithms to the commissioning sensor data to identify boundaries between regions of high and low electromagnetic radiation detection on the sensor; identifying one or more regions bounded by the identified boundaries; and classifying the identified one or more regions as the one or more nominal zones.

[0040] Determining the nominal pattern may comprise: filtering detected electromagnetic radiation based on at least one of wavelength, polarisation, and temporal characteristics to isolate electromagnetic radiation emitted by the emitter from ambient electromagnetic radiation; identifying regions of the sensor where the isolated electromagnetic radiation is detected; and classifying the identified regions as the one or more nominal zones.

[0041] Comparing subsequently detected electromagnetic radiation to the nominal pattern may comprise: identifying one or more zones of a sensor of the sensor module at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

[0042] Identifying the one or more zones may comprise: analysing intensity distribution across the sensor to identify pixels where electromagnetic radiation above a threshold intensity is detected; and identifying contiguous regions of pixels detecting electromagnetic radiation as the one or more zones.

[0043] Identifying the one or more zones may comprise: applying edge detection algorithms to identify boundaries of regions where electromagnetic radiation is detected on the sensor; and classifying regions bounded by the identified boundaries as the one or more zones.

[0044] Comparing the zones to the one or more nominal zones may comprise calculating a spatial overlap between the one or more zones and the one or more nominal zones.

[0045] Comparing the zones to the one or more nominal zones may comprise determining a positional offset between a centroid of the one or more zones and a centroid of the one or more nominal zones.

[0046] Comparing the one or more zones to the one or more nominal zones of the nominal pattern may comprise determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

[0047] The difference may comprise at least one of: a spatial difference in position on the sensor between the one or more zones and the one or more nominal zones; an intensity difference between electromagnetic radiation detected in the one or more zones and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase; a shape difference between the one or more zones and the one or more nominal zones; and a size difference between the one or more zones and the one or more nominal zones.

[0048] Determining the difference may comprise: calculating a weighted average position of detected electromagnetic radiation within the one or more zones by weighting each pixel's coordinates by its detected intensity; comparing the weighted average position to a weighted average position of the one or more nominal zones; and determining a positional deviation based on the comparison.

[0049] The obstruction indication output may be generated when the difference is greater than a difference threshold.

[0050] The difference threshold may be at least one of: a surface area overlap threshold, the surface area overlap threshold defining a minimum acceptable overlap between the one or more zones and the one or more nominal zones; a positional deviation threshold, the positional deviation threshold defining a maximum acceptable positional offset between the one or more zones and the one or more nominal zones; and an intensity deviation threshold, the intensity deviation threshold defining a maximum acceptable difference in intensity between electromagnetic radiation detected in the one or more zones during the operating phase and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase.

[0051] The obstruction indication output may be configured to change an operating parameter of an apparatus associated with the obstruction detection system.

[0052] The apparatus may be positioned within, or near, a detection zone between the emitter and the detector, thereby being associated with the obstruction detection system. The operating parameter may comprise at least one of a speed of a movable component of the apparatus, a position of a movable component of the apparatus, and an operational state of the apparatus. Changing the operating parameter may comprise at least one of reducing the speed of the moveable component, initiating a controlled stop sequence of the apparatus, altering a trajectory of the movable component, and initiating an emergency stop procedure for the apparatus.

[0053] The apparatus may comprise a piece of industrial equipment.

[0054] The obstruction detection system may further comprise at least one of: an optical filter that is configured to filter electromagnetic radiation that is incident to the sensor based on a wavelength of the electromagnetic radiation; and a polariser that is configured to enable electromagnetic radiation with a specific polarisation to pass through while blocking electromagnetic radiation with other polarisations.

[0055] The obstruction detection system may be further configured to adjust the nominal pattern based on environmental conditions.

[0056] Adjusting the nominal pattern based on environmental conditions may comprise: detecting a change in a value of at least one parameter indicating a state of an environment of the obstructiondetection system; measuring a shift in position of the one or more nominal zones on the sensor resulting from the detected change in environmental conditions; determining that the measured shift exceeds an adjustment threshold; and updating the nominal pattern to reflect the shifted position of the one or more nominal zones.

[0057] The obstruction detection system may further comprise the emitter. The emitter may comprise a plurality of emission units, each being configured to emit electromagnetic radiation at the detector. The detector may comprise a plurality of sensor modules. Each emission unit may be configured to emit electromagnetic radiation at a respective sensor module.

[0058] The obstruction detection system may be further configured to: designate one or more regions of the detector that correspond to an expected movement path of an apparatus during normal operation of the apparatus as dynamic exclusion zones of the detector; and selectively disregard sensor data generated by sensor modules of the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected apparatus movement.

[0059] Comparing subsequently detected electromagnetic radiation to the nominal pattern may comprise: processing pixel data from the sensor in a row-by-row manner by reading out pixel data from the sensor one row at a time; identifying one or more groups of pixels within one or more rows of pixels of the sensor that comprise a pixel where electromagnetic radiation above a threshold intensity is detected; identifying a high intensity pixel within each group that detects electromagnetic radiation with the highest intensity value within the respective group; determining a first sensor coordinate and a second sensor coordinate of each high intensity pixel on the sensor; and comparing the first sensor coordinate and the second sensor coordinate of the high intensity pixels to coordinates of pixels within the nominal zone to determine whether the subsequently detected electromagnetic radiation differs from the nominal pattern.

[0060] In some embodiments of the present disclosure there is provided an obstruction detection system. The obstruction detection system may comprise: a detector comprising a plurality of sensor modules, each sensor module being configured to detect electromagnetic radiation that is: emitted by an emitter; and incident to a sensor of the sensor module; wherein the obstruction detection system is configured to: record commissioning sensor data for each sensor module, using the respective sensor module, during a commissioning phase in which the sensor modules detect electromagnetic radiation emitted by the emitter; determine, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; compare electromagnetic radiation that is subsequently detected, during an operating phase, by each of the sensor modules, to the nominal pattern of the respective sensor module; and generate an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing from the nominal pattern of that sensor module.

[0061] The obstruction detection system may be configured to transmit the obstmction indication output to an apparatus to change an operating parameter of the apparatus.

[0062] In some embodiments of the present disclosure, there is provided a method. The method may comprise: recording commissioning sensor data, using a sensor module, during a commissioning phase of an obstruction detection system in which the sensor module detects electromagnetic radiation emitted by an emitter; determining a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; comparing subsequently detected electromagnetic radiation, that is emitted by the emitter and detected by the sensor module during an operating phase, to the nominal pattern; and generating an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

[0063] The method may further comprise changing an operating parameter of an apparatus associated with the obstruction detection system in response to the generation of the obstruction indication output.

[0064] The apparatus may be positioned within, or near, a detection zone between the emitter and a detector of the obstruction detection system, thereby being associated with the obstruction detection system.

[0065] Recording the commissioning sensor data may comprise: sampling a sensor of the sensor module, during the commissioning phase, to determine the commissioning sensor data that indicates at least one characteristic of electromagnetic radiation incident to the sensor during a period of the commissioning phase; and storing, in a memory, the commissioning sensor data.

[0066] The at least one characteristic may comprise at least one of: a spatial distribution of electromagnetic radiation detected by the sensor; an intensity of electromagnetic radiation detected by the sensor; a wavelength of electromagnetic radiation detected by the sensor; a polarisation of electromagnetic radiation detected by the sensor; a timing of detection of electromagnetic radiation by the sensor; and x-y coordinates of pixels of a sensor of the sensor module at which electromagnetic radiation is detected.

[0067] Determining the nominal pattern comprises identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

[0068] Determining the nominal pattern may comprise: identifying areas of peak intensity on the sensor where electromagnetic radiation emitted by the emitter is detected above a threshold intensity; and classifying the identified areas of peak intensity as the one or more nominal zones.

[0069] Determining the nominal pattern may comprise: establishing an intensity threshold; classifying pixels detecting electromagnetic radiation emitted by the emitter with intensity above the intensity threshold as part of the one or more nominal zones; and storing x-y coordinates of the classified pixels in a memory of the obstruction detection system.

[0070] Determining the nominal pattern may comprise: determining a maximum detected intensity of electromagnetic radiation emitted by the emitter and detected by the sensor; identifying regions of the sensor where intensity exceeds a percentage of the maximum detected intensity; and classifying the identified regions as the one or more nominal zones.

[0071] Determining the nominal pattern may comprise: applying edge detection algorithms to the commissioning sensor data to identify boundaries between regions of high and low electromagnetic radiation detection on the sensor; identifying one or more regions bounded by the identified boundaries; and classifying the identified one or more regions as the one or more nominal zones.

[0072] Determining the nominal pattern may comprise: filtering detected electromagnetic radiation based on at least one of wavelength, polarisation, and temporal characteristics to isolate electromagnetic radiation emitted by the emitter from ambient electromagnetic radiation; identifying regions of the sensor where the isolated electromagnetic radiation is detected; and classifying the identified regions as the one or more nominal zones.

[0073] Comparing subsequently detected electromagnetic radiation to the nominal pattern may comprise: identifying one or more zones of a sensor of the sensor module at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

[0074] Identifying the one or more zones may comprise: analysing intensity distribution across a sensor of the sensor module to identify pixels where electromagnetic radiation above a threshold intensity is detected; and identifying contiguous regions of pixels detecting electromagnetic radiation as the one or more zones.

[0075] Identifying the one or more zones may comprise: applying edge detection algorithms to identify boundaries of regions where electromagnetic radiation is detected on the sensor; and classifying regions bounded by the identified boundaries as the one or more zones.

[0076] Comparing the zones to the one or more nominal zones may comprise calculating a spatial overlap between the one or more zones and the one or more nominal zones.

[0077] Comparing the zones to the one or more nominal zones may comprise determining a positional offset between a centroid of the one or more zones and a centroid of the one or more nominal zones.

[0078] Comparing the one or more zones to the one or more nominal zones of the nominal pattern may comprise determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

[0079] The difference may comprise at least one of: a spatial difference in position on the sensor between the one or more zones and the one or more nominal zones; an intensity difference between electromagnetic radiation detected in the one or more zones and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase; a shape difference between the one or more zones and the one or more nominal zones; and a size difference between the one or more zones and the one or more nominal zones.

[0080] Determining the difference may comprise: calculating a weighted average position of detected electromagnetic radiation within the one or more zones by weighting each pixel's coordinates by its detected intensity; comparing the weighted average position to a weighted average position of the one or more nominal zones; and determining a positional deviation based on the comparison.

[0081] The obstruction indication output may be generated when the difference is greater than a difference threshold.

[0082] The difference threshold may be at least one of: a surface area overlap threshold, the surface area overlap threshold defining a minimum acceptable overlap between the one or more zones and the one or more nominal zones; a positional deviation threshold, the positional deviation threshold defining a maximum acceptable positional offset between the one or more zones and the one or more nominal zones; and an intensity deviation threshold, the intensity deviation threshold defining a maximum acceptable difference in intensity between electromagnetic radiation detected in the one or more zones during the operating phase and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase.

[0083] The obstruction indication output may be configured to change an operating parameter of an apparatus associated with the obstruction detection system.

[0084] The apparatus may be positioned within, or near, a detection zone between the emitter and the detector, thereby being associated with the obstruction detection system. The operating parameter may comprise at least one of a speed of a movable component of the apparatus, a position of a movable component of the apparatus, and an operational state of the apparatus. Changing the operating parameter may comprise at least one of reducing the speed of the moveable component, initiating a controlled stop sequence of the apparatus, altering a trajectory of the movable component, and initiating an emergency stop procedure for the apparatus.

[0085] The apparatus may comprise a piece of industrial equipment.

[0086] The method may further comprise adjusting the nominal pattern based on environmental conditions.

[0087] Adjusting the nominal pattern based on environmental conditions may comprise: detecting a change in a value of at least one parameter indicating a state of an environment; measuring a shift in position of the one or more nominal zones on the sensor resulting from the detected change in environmental conditions; determining that the measured shift exceeds an adjustment threshold; and updating the nominal pattern to reflect the shifted position of the one or more nominal zones.

[0088] The method may further comprise: designating one or more regions of a detector that correspond to an expected movement path of an apparatus during normal operation of the apparatus as dynamic exclusion zones of the detector; and selectively disregarding sensor data generated by sensor modules of the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected apparatus movement.

[0089] Comparing subsequently detected electromagnetic radiation to the nominal pattern may comprise: processing pixel data from a sensor of an obstruction detection system in a row -by -row manner by reading out pixel data from the sensor one row at a time; identifying one or more groups of pixels within one or more rows of pixels of the sensor that comprise a pixel where electromagnetic radiation above a threshold intensity is detected; identifying a high intensity pixel within each group that detects electromagnetic radiation with the highest intensity value within the respective group; determining a firstsensor coordinate and a second sensor coordinate of each high intensity pixel on the sensor; and comparing the first sensor coordinate and the second sensor coordinate of the high intensity pixels to coordinates of pixels within the nominal zone to determine whether the subsequently detected electromagnetic radiation differs from the nominal pattern.

[0090] In some embodiments of the present disclosure, there is provided a method. The method may comprise: recording commissioning sensor data for each of a plurality of sensor modules, using the respective sensor module, during a commissioning phase of an obstruction detection system in which the sensor modules detect electromagnetic radiation emitted by the emitter; determining, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; comparing electromagnetic radiation that is subsequently detected, during an operating phase of the obstruction detection system, by each of the sensor modules, to the nominal pattern of the respective sensor module; and generating an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing the nominal pattern of that sensor module.

[0091] The method may further comprise transmitting the obstruction indication output to an apparatus to change an operating parameter of the apparatus.

[0092] The method may further comprise changing a value of an operating parameter of an apparatus in response to the generation of the obstruction indication output.BRIEF DESCRIPTION OF THE DRAWINGS

[0093] Embodiments of the disclosure are described further below, by way of example only, with reference to the accompanying Drawings, in which:Figure 1 illustrates components of a light curtain, according to aspects of the present disclosure;Figure 2 shows a plurality of time series emission profdes of emitters of the light curtain of Figure 1, according to aspects of the present disclosure;Figures 3 and 4 show schematic views of a light emitting diode and photodiode pair of the light curtain of Figure 1, with an obstruction therebetween, according to aspects of the present disclosure;Figures 5, 6, and 7 depict schematic diagrams of different alignment configurations for light emitting diode and photodiode pairs of the light curtain of Figure 1, according to aspects of the present disclosure; Figure 8 illustrates a schematic diagram of an alternative light curtain system, according to aspects of the present disclosure;Figure 9 shows a process flow diagram of a method for detecting obstructions, according to some embodiments of the present disclosure;Figure 10 shows a schematic diagram of an emission unit and sensor module pair of an obstruction detection system, according to some embodiments of the present disclosure;Figure 11 shows a schematic diagram of the emission unit and sensor module pair of Figure 10, with an obstruction therebetween, according to some embodiments of the present disclosure;Figure 12 shows a schematic diagram of the emission unit and sensor module pair of Figure 10, with an obstruction therebetween and a nearby mirror, according to some embodiments of the present disclosure; Figure 13 shows a schematic diagram of the emission unit and sensor module pair of Figure 10, with a mirror nearby, according to some embodiments of the present disclosure;Figures 14, 15, and 16 show schematic diagrams of example emission unit and sensor module pairs, according to some embodiments of the present disclosure;Figure 17 shows a schematic diagram of an emission unit and sensor module pair with a pentamirror system, according to some embodiments of the present disclosure;Figure 18 depicts graphical representations of sensor data obtained during a commissioning phase, according to some embodiments of the present disclosure;Figure 19 illustrates another graphical representation of commissioning sensor data, according to some embodiments of the present disclosure;Figure 20 shows a schematic diagram of parts of an obstruction detection system, according to some embodiments of the present disclosure;Figure 21 shows a timing diagram for an obstruction detection system, according to some embodiments of the present disclosure;Figure 22 shows another schematic diagram of a part of the obstruction detection system, according to some embodiments of the present disclosure;Figure 23 is a block diagram of a part of the obstruction detection system, according to some embodiments of the present disclosure;Figure 24 is a block diagram of the obstruction detection system, according to some embodiments of the present disclosure;Figures 25 and 26 show different views of one or more detectors of the obstruction detection system, according to embodiments;Figure 27 depicts a perspective view of a detector of the obstruction detection system, with internal components visible, according to some embodiments of the present disclosure;Figure 28 depicts a perspective, sectional view of the detector of Figure 27, according to some embodiments of the present disclosure.Figures 29, 30 and 31 show perspective views of one or more emitters of the obstruction detection system, according to some embodiments of the present disclosure;Figures 32 shows a perspective view of an internal portion of a detector of the obstruction detection system, according to some embodiments of the present disclosure;Figure 33 shows a perspective view of an emitter installed in an industrial setting, according to some embodiments of the present disclosure;Figures 34 and 35 illustrate isometric views of an obstruction detection system integrated with industrial machinery, according to some embodiments of the present disclosure;Figures 36 and 37 show views of the obstruction detection system integrated with industrial machinery in different operational states, according to some embodiments of the present disclosure;Figure 38 shows a view of the obstruction detection system integrated with industrial machinery, with the emitter of the obstruction detection system taking a first configuration where a first part of the industrial machinery is monitored, according to some embodiments of the present disclosure;Figure 39 shows a view of the obstruction detection system integrated with industrial machinery, with the emitter of the obstruction detection system taking a second configuration where a first part and a second part of the industrial machinery is monitored, according to some embodiments of the present disclosure; Figure 40 shows a view of the obstruction detection system integrated with industrial machinery, with the emitter of the obstruction detection system taking a third configuration where a first part, second part and third part of the industrial machinery is monitored, according to some embodiments of the present disclosure;Figure 41 shows a schematic timeline of a method in which the emission units and planar testing emission units are used during an operating phase of the obstruction detection system, according to some embodiments of the present disclosure;Figure 42 shows a number of plan views of the face of a sensor and where incident electromagnetic radiation is detected on the sensor during a commissioning phase and an operating phase of the obstruction detection system, according to some embodiments of the present disclosure;Figure 43 shows a number of plan views of the sensor of Figure 42 and where incident electromagnetic radiation is detected on the sensor during a subsequent operating phase of the obstruction detection system, according to some embodiments of the present disclosure;Figure 44 shows a number of plan views of the sensor of Figure 42 and where incident electromagnetic radiation is detected on the sensor during a re-commissioning of the obstruction detection system and a subsequent operating phase, according to some embodiments of the present disclosure;Figure 45 shows a sensor array of a detector of the obstruction detection system, in which a plurality of exclusion zones are defined, according to some embodiments of the present disclosure;Figure 46 shows a close-up schematic view of a sensor and where electromagnetic radiation emitted by a corresponding emission unit is detected on the sensor, according to some embodiments of the present disclosure;Figure 47 shows a schematic representation of a detector of the obstruction detection system, with sensor modules arranged in a linear array, according to some embodiments of the present disclosure;Figure 48 depicts a schematic representation of a sensor and row-by-row processing of pixel data, according to some embodiments of the present disclosure;Figure 49 illustrates a schematic diagram of an optical system configured to direct electromagnetic radiation from multiple detection zones onto a single sensor, according to some embodiments of the present disclosure;Figure 50 shows another view of the optical system of Figure 49, according to some embodiments of the present disclosure;Figure 51 depicts electromagnetic radiation from multiple optical channels converging towards a sensor, according to some embodiments of the present disclosure;Figure 52 shows top view of the sensor of Figure 51, with electromagnetic radiation from multiple optical channels incident on distinct regions of the sensor, according to some embodiments of the present disclosure;Figure 53 illustrates a sensor receiving electromagnetic radiation from eight separate optical channels, according to some embodiments of the present disclosure;Figure 54 shows an alternative arrangement of an optical system with four optical channels, according to some embodiments of the present disclosure;Figure 55 depicts another alternative arrangement of an optical system with four optical channels, each including a respective focusing lens, according to some embodiments of the present disclosure; and Figure 56 shows a further alternative arrangement of an optical system with redirecting mirrors and a common focusing lens, according to some embodiments of the present disclosure.DETAILED DESCRIPTION

[0094] Specific embodiments of the present disclosure will now be described by way of example only. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the disclosed system or method. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art to pertaining the present disclosure. In the drawings, it should be understood that like reference numbers refer to like parts.

[0095] Referring to Figures 1 to 8, a laser curtain system 10 may be used for detecting obstructions. The laser curtain system 10 comprises an emitter array and a detector array, as shown in Figure 1. The emitter array includes multiple light emitting diodes 12. The light emitting diodes 12 are arranged vertically. The detector array includes multiple photodiodes 14. The photodiodes 14 are arranged vertically, opposite the light emitting diodes 12.

[0096] In operation, the light emitting diodes 12 emit electromagnetic radiation 18 sequentially, as illustrated in Figure 2. Each light emitting diode 12 emits a burst of light pulses at a specific time, with the timing staggered between different light emitting diodes 12. This sequential activation allows the corresponding photodiodes 14 to detect which light emitting diode 12 is active at any given moment.

[0097] Figure 3 shows how the laser curtain system 10 detects an obstruction 16. A light emitting diode 12 emits electromagnetic radiation 18 along a propagation path 20 towards a photodiode 14. When an obstruction 16 blocks the propagation path 20 (i.e. blocks the electromagnetic radiation 18), the photodiode 14 does not detect the expected electromagnetic radiation 18, indicating the presence of the obstruction 16.

[0098] However, the laser curtain system 10 may have limitations in certain scenarios. As shown in Figure 4, if a mirror 22 is present above or near the obstruction 16, some of the electromagnetic radiation 18 may be reflected around the obstruction 16 and still reach the photodiode 14. This may result in the obstruction 16 not being detected.

[0099] Laser curtains 10 are also highly sensitive to proper alignment of light emitting diodes 12 and photodiodes 14. Figures 5, 6, and 7 illustrate the importance of alignment in the laser curtain system 10. Figure 5 shows a properly aligned configuration, where the light emitting diode 12 emits electromagnetic radiation 18 with a small divergence angle 24 directly towards the photodiode 14. In Figure 6, the light emitting diode 12 is misaligned, with respect to the photodiode 14, causing the emitted electromagnetic radiation 18 to miss the photodiode 14. Similarly, Figure 7 shows a misaligned photodiode 14, which may not detect the incoming electromagnetic radiation 18 properly, even when the light emitting diode 12 is properly aligned. Thus, small misalignments between the light emitting diodes 112 and photodiodes 14 of a laser curtain can have a substantive effect on the functionality of the system.

[0100] Figure 8 demonstrates an alternative configmation of the laser curtain system 10 that includes mirrors 26. In this arrangement, the electromagnetic radiation 18 from a light emitting diode 12 is reflected by two mirrors 26 before reaching the photodiode 14. This configuration allows for detection of obstructions along multiple planes, but again, the system is highly sensitive to changes in orientation of the light emitting diodes 12, the photodiode 14 and / or the mirrors 26.Obstruction Detection System 100

[0101] Figures 23 and 24 show an obstruction detection system 100, according to some embodiments of the present disclosure. The obstruction detection system 100 is used for detecting obstructions. In particular, the obstruction detection system 100 enables the detection of an obstruction that is between an emitter array and a detector array of the system 100. The obstruction detection system 100 provides improved detection capabilities compared to conventional laser curtain systems.

[0102] Referring to Figure 24, the obstruction detection system 100 comprises at least one emitter 140. The illustrated obstruction detection system 100 comprises a plurality of emitters 140. Each emitter 140 may alternatively be referred to as an emission module. The emitters 140 form an emitter array. The emitter array comprises a plurality of emitters 140. That is, the emitter array comprises a plurality of emission modules.

[0103] The obstruction detection system 100 comprises at least one detector 130. The illustrated obstruction detection system 100 comprises a plurality of detectors 130. Each detector 130 may alternatively be referred to as a detection module. The detectors 130 form a detector array. The detection array comprises a plurality of detectors 130. That is, the detector array comprises a plurality of detection modules.

[0104] The emitters 140 and detectors 130 are arranged in pairs. Each pair comprises a respective emitter 140 and detector 130. An emitter 140, detector 130 pair may be referred to as an obstruction detection module. Emitters 140 and detectors 130 are arranged in pairs such that a detection zone is provided between each paired emitter 140 and detector 130. The obstruction detection system 100 uses pairs of emitters 140 and detectors 130 to detect obstructions located in the detection zone between a respective emitter 140, detector 130 pair, in use.

[0105] The obstruction detection system 100 comprises at least one processor 102. The obstruction detection system 100 comprises memory 104. The memory 104 is accessible by the at least one processor102. The memory stores computer-executable instructions. The computer-executable instructions may be referred to as program instructions. The at least one processor 102 is operably connected to memory 104. That is, the at least one processor 102 is configured to communicate with memory 104. The computerexecutable instructions are accessible by the at least one processor 102. The at least one processor 102 is configured to execute the computer-executable instructions. The at least one processor 102 executes the computer-executable instructions to perform certain functionality described herein. For example, the at least one processor 102 controls the operation of the emitters 140 and the detectors 130. That is, the at least one processor 102 executes the computer-executable instruction stored in memory 104 to control the emitters 104. The at least one processor 102 executes the computer-executable instructions stored in memory 104 to control the detectors 130. The computer-executable instructions may comprise executable program code modules that are configured to be executed by the at least one processor 102.

[0106] The at least one processor 102 comprises one or more microprocessors, central processing units (CPUs), application specific instruction set processors (ASIPs), application specific integrated circuits (ASICs), tensor processing units (TPUs), field programable gate array (FPGA), programmable logic devices (PLDs), systems on a chip (SOC), graphical processing units (GPUs) or other processors capable of reading and executing computer-executable instructions. The at least one processor 102 may comprise a plurality of processors. It will be appreciated that the at least one processor 102 may be a distributed processor. That is, one or more processor of the at least one processor 102 may be physically separated from one or more other processor of the at least one processor 102.

[0107] Memory 104 may comprise one or more volatile or non-volatile memory types. Memory 104 may comprise at least one of random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM) and flash memory. Memory 104 may comprise one or more computer-readable storage medium. A computer readable storage medium can be any medium that can tangibly contain or store computer executable instructions. In some examples, the storage medium is a transitory computer readable storage medium. In some examples, the storage medium is a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium can include, but is not limited to, magnetic, optical, and / or semiconductor storages. Examples of such storage include magnetic disks, optical discs based on CD, DVD, or Blu-ray technologies, as well as persistent solid-state memory such as flash, solid state drives, and the like.

[0108] In some embodiments, the obstruction detection system 100 comprises a field programable gate array (FPGA). The at least one processor 102 may comprise at least one FPGA. The at least one processor 102 may comprise a plurality of FPGAs. For example, the at least one processor 102 may comprise a first processor that is operably connected to one or more of the emission units 112. This first processor may comprise a first FPGA. The at least one processor 102 may comprise a second processor that is operably connected to one or more of the sensor modules 114. This second processor may comprise an FPGA. The functionality of the obstruction detection system 100 described herein is, in some embodiments, performed by the FPGA. In some embodiments, the obstruction detection system 100 comprises one or more programmable logic devices (PLDs). The functionality of the obstruction detection system 100described herein is, in some embodiments, performed by the PLDs. Thus, the at least one processor 102 performing certain functionality herein, may be performed via executing computer-executable instructions, or by performing the functionality through the hardware configuration of the at least one processor 102. In such embodiments, the FPGA or PLD may be configured with logic circuits that directly implement the described functionality without executing sequential instructions from memory 104. The configuration of the FPGA or PLD may be defined by configuration data, such as a bitstream, that establishes the interconnections and logic functions within the FPGA or PLD. References herein to the at least one processor 102 executing computer-executable instructions should be understood to encompass both instruction-based execution by processors such as CPUs and microprocessors, as well as hardware-based implementation of equivalent functionality by configured FPGAs or PLDs.

[0109] The obstruction detection system 100 comprises a network interface (not shown). The network interface is configured to enable the obstruction detection system 100 to communicate with other computing devices, such as industrial machinery or an apparatus. The obstruction detection system 100 may communicate with other computing devices via a communications network. The network interface may comprise a combination of network interface hardware and network interface software suitable for establishing, maintaining and facilitating communication between the obstruction detection system 100 and another computing device, over a relevant communications network.

[0110] An emitter 140 comprises at least one emission unit 112. That is, an emitter 140 comprises an emission unit 112. In the illustrated embodiment, each emitter 140 comprises a plurality of emission units 112. It will be appreciated that in some embodiments, a first emitter 140 may comprise a different number of emission units 112 to a second emitter 140. An emission unit 112 is configured to emit electromagnetic radiation 118. Emission units 112 are arranged in an emission unit array of the respective emitter 140. In some cases, the emission units 112 are arranged in a linear array within the emitter 140. Each emission unit 112 is spaced apart from another of the emission units 112 of that emitter 140 by an emission unit spacing. In the illustrated embodiment, the emission unit spacing for each pair of adjacent emission units 112 is equal. The emission units 112 of an emitter 140 are colinear.

[0111] It will be appreciated that in some embodiments, the emission units 112 may be arranged in another configuration. In some embodiments, the emission units 112 may be arranged in a two-dimensional grid or matrix pattern on the emitter 140. This may enable detection across a broader planar area. This may provide enhanced spatial resolution. The emission units 112 may be arranged in a curved or arcuate configuration. This may be advantageous for monitoring cylindrical or curved work areas. In some cases, the emission units 112 may be arranged in a staggered or offset pattern. Alternating emission units 112 may be positioned at different depths or lateral positions. This may improve detection coverage. This may reduce blind spots. The emission unit spacing between adjacent emission units 112 may vary across the emitter 140. Closer spacing may be used in regions requiring higher detection resolution. Wider spacing may be used where lower resolution is acceptable. In some implementations, the emission units 112 may be arranged in a radial pattern extending outward from a central point. This may be suitable for monitoring areas around rotating machinery. Multiple groups of emission units 112may be arranged in different orientations within a single emitter 140. For example, horizontal and vertical linear arrays may be combined. This may enable simultaneous monitoring of multiple planes or directions.

[0112] A detector 130 comprises at least one sensor module 114. That is, a detector 130 comprises a sensor module 114. In the illustrated embodiment, each detector 130 comprises a plurality of sensor modules 114. It will be appreciated that in some embodiments, a first detector 130 may comprise a different number of sensor modules 114 to a second detector 130. Each sensor module 114 is configured to detect electromagnetic radiation. In particular, each sensor module 114 is configured to detect the electromagnetic radiation 118 emitted by a corresponding emission unit 112. Sensor modules 114 are arranged in a sensor module arrangement of the respective detector 140. In some cases, the sensor modules 114 are arranged in a linear array within the detector 130, corresponding to the arrangement of the emission units 112 in the emitter 140. Each sensor module 114 is spaced apart from another of the sensor modules 114 of that detector 130 by a sensor module spacing. In the illustrated embodiment, the sensor module spacing for each pair of adjacent sensor modules 114 is equal. The sensor modules 114 of a detector 130 are colinear.

[0113] It will be appreciated that in some embodiments, the sensor modules 114 may be arranged in another configuration. The configuration of the sensor modules 114 corresponds to the configuration of the emission units 112. That is, as the system 100 comprises a plurality of pairs of emission units 112 and sensor modules 114, the physical configuration of the emission units 112 maps to that of the sensor modules 114. In some embodiments, the sensor modules 114 may be arranged in a two-dimensional grid or matrix pattern on the detector 130. The sensor modules 114 may be arranged in a curved or arcuate configuration. In some cases, the sensor modules 114 may be arranged in a staggered or offset pattern. The sensor modules 114 may be arranged in various geometric configurations including linear arrays, L-shaped configurations, U-shaped configurations, or square or rectangular perimeter arrangements. Alternating sensor modules 114 may be positioned at different depths or lateral positions. The sensor module spacing between adjacent sensor modules 114 may vary across the detector 130. Closer spacing may be used in regions requiring higher detection resolution. Wider spacing may be used where lower resolution is acceptable. In some implementations, the sensor modules 114 may be arranged in a radial pattern extending outward from a central point. Multiple groups of sensor modules 114 may be arranged in different orientations within a single detector 130. For example, horizontal and vertical linear arrays may be combined. This may enable simultaneous monitoring of multiple planes or directions.

[0114] The at least one processor 102 is operably connected to a detector 130. In particular, the at least one processor 102 is operably connected to each of the detectors 130. The at least one processor 102 is operably connected to an emitter 140. In particular, the at least one processor 102 is operably connected to each of the emitters 140. The at least one processor 102 is configured to control the operation of the obstruction detection system 100 and process data received from the detectors 130. That is, the at least one processor 102 controls operation of the emitters 140. The at least one processor 102 controls operation of the detectors 140. In some embodiments, the FPGA and / or PLDs (of certain embodiments ofthe at least one processor 102) are operably connected to the detectors 130 and emitters 140. The FPGA and / or PLDs in such cases are configured to control the operation of the obstruction detection system 100 and process data received from the detectors 130.

[0115] In some embodiments, the at least one processor 102 may comprise a plurality of hardware-based processors, such as FPGAs or PLDs. Each emitter 140 and / or detector 130 may comprise its own dedicated processor 102 of the at least one processor 102. In such distributed processing architectures, each dedicated processor 102 may independently control the operation of its respective emitter 140 or detector 130. This may include controlling emission timing, sensor readout, and local data processing. The dedicated processors may be operably connected to a central processor or controller that coordinates operation across multiple emitters 140 and detectors 130, synchronizes emission and detection timing between different emitter-detector pairs, and aggregates data from multiple units to make system-level decisions such as generating obstruction indication outputs. This distributed processing approach may reduce communication bandwidth requirements, enable parallel processing of data from multiple sensor modules 114, and allow for modular scalability of the obstruction detection system 100.

[0116] In some embodiments, a common processor of the at least one processor 102 may control both the emitter 140 and the detector 130 of a particular emitter-detector pair. In such embodiments, the common processor may coordinate the emission of electromagnetic radiation 118 by the emission units 112 of the emitter 140 with the detection operations of the sensor modules 114 of the corresponding detector 130, ensuring precise timing synchronisation between emission and detection. This integrated control may enable the processor to directly correlate emitted electromagnetic radiation patterns with detected patterns, perform real-time comparison of detected electromagnetic radiation to the nominal pattern, and generate obstruction indication outputs based on data from that specific emitter-detector pair. The single processor may communicate with other processors controlling other emitter-detector pairs, or with a central processor, to coordinate system-wide operation and share obstruction detection information across multiple detection zones.

[0117] Referring now to Figure 23, a schematic diagram of a number of the components of the obstruction detection system 100 is provided. Each emitter 140 of the obstruction detection system 100 is associated with a corresponding detector 130. The detector 130 of an emitter-detector pair detects electromagnetic radiation emitted by the emitter 140 of that pair. The emitter 140 of an emitter-detector pair comprises one or more emission units 112. Similarly, the detector 130 of the emitter-detector pair comprises one or more sensor modules 114. In the illustrated embodiment, each emission unit 112 is associated with a respective sensor module 114. The sensor module 114 that is associated with a particular emission unit 112 is configured to detect electromagnetic radiation emitted by the associated emission unit 112, in use. In particular, each sensor module 114 of a particular detector 130 detects electromagnetic radiation emitted by a corresponding emission unit 112 of the emitter 140 of that pair. Thus, each sensor module 114 is associated with a respective emission unit 130.

[0118] It will be appreciated that in some embodiments, the ratio between emission units 112 and sensor modules 114 may differ from one-to-one. A detector 130 may comprise more sensor modules 114than the number of emission units 112 in the corresponding emitter 140. This configuration may enable multiple sensor modules 114 to detect electromagnetic radiation from a single emission unit 112 from different angles or positions. This may provide redundancy in detection. This may enhance the system's 100 ability to detect obstructions in complex environments where electromagnetic radiation may be reflected or scattered. This may improve detection accuracy by enabling triangulation or multi-angle analysis of the emitted electromagnetic radiation. Alternatively, an emitter 140 may comprise more emission units 112 than the number of sensor modules 114 in the corresponding detector 130. This configuration may enable a single sensor module 114 to detect electromagnetic radiation from multiple emission units 112. This may reduce the overall number of sensor modules 114 required. This may simplify the detector 130 design. This may reduce manufacturing costs. This may be advantageous where the detection zone of the environment requires coverage from multiple angles or directions but a single sensor module 114 with a wide field of view is sufficient for detection. The particular ratio of emission units 112 to sensor modules 114 may be selected based on factors such as the geometry of the detection zone, the required detection resolution, cost constraints, and the complexity of the industrial environment.

[0119] An emitter 140 comprises multiple emission units 112. Each emission unit 112 is configured to emit electromagnetic radiation 118 towards a corresponding sensor module 114 in the respective detector 130. The emission units 112 may include various types of electromagnetic radiation sources. In some cases, one or more of the emission units 112 are light emitting diodes (LEDs). In some cases, one or more of the emission units 112 are lasers. The emission units 112 may be selected to emit electromagnetic radiation 118 at specific wavelengths, such as infrared, visible light, or ultraviolet. That is, an emission unit 112 may emit electromagnetic radiation within a target electromagnetic radiation frequency spectrum. The target electromagnetic radiation frequency spectrum may be bound by an upper frequency limit and a lower frequency limit.

[0120] In some implementations, the emission units 112 may include laser diodes, which can provide focused and coherent electromagnetic radiation. The emission units 112 may also incorporate optical elements, such as lenses or diffusers, to shape the emitted electromagnetic radiation 118 as needed for the specific application. The optical elements may include collimating lenses to produce a parallel beam of electromagnetic radiation 118, or diverging lenses to create a wider coverage area. In some cases, beamshaping optics may be used to produce specific beam profdes, such as elliptical or rectangular crosssections, which may be advantageous for particular detection geometries or industrial applications. In some embodiments, the emission units 112 may be configurable to emit electromagnetic radiation 118 with different characteristics, such as varying intensities, pulse patterns, wavelengths or polarisation. The emission units 112 may emit electromagnetic radiation 118 according to emission profiles with defined characteristics. The intensity of the emitted electromagnetic radiation 118 may be adjusted to suit different detection ranges or environmental conditions. The pulse pattern may be varied to enable time-division multiplexing between multiple emission units 112. Different wavelengths may be selected to optimise detection in specific industrial environments or to avoid interference from ambient light sources. The polarisation of the emitted electromagnetic radiation 118 may be configured to enhancedetection capabilities or to enable differentiation between multiple emission units 112 operating simultaneously.

[0121] The detector 130 comprises multiple sensor modules 114. The arrangement of the sensor modules 114 of the detector 130 is such that it corresponds to the arrangement of the emission units 112 of the associated emitter 140. Each sensor module 114 includes a sensor 110. The sensor 110 comprises a plurality of pixels that detect and respond to incident electromagnetic radiation. Each pixel may generate an electrical signal in response to incident electromagnetic radiation 118. The sensor 110 may convert the pattern of incident electromagnetic radiation 118 into electrical signals that can be processed by the at least one processor 102. For example, where the at least one processor 102 comprises an FPGA, the FPGA may process the electrical signals. Each sensor module 114 includes an optical system 113. The optical system 113 is configured to receive the electromagnetic radiation 118 from the corresponding emission unit 112, when the emission unit 112 and the sensor module 114 are aligned. The optical system 113 focuses the incoming electromagnetic radiation 118 onto the sensor 110. In some cases, the optical system 113 comprises one or more lenses or other optical elements to manipulate the incoming electromagnetic radiation 118.

[0122] The sensor 110 comprises a plurality of pixels arranged in a two-dimensional array. Each pixel is indexed by x and y coordinates. Each pixel is configured to detect characteristics of incident electromagnetic radiation 118. These characteristics may include intensity, colour, wavelength, and / or timing of the incident electromagnetic radiation 118. Each pixel generates an electrical signal corresponding to the detected characteristics. The x-y indexing of the pixels enables the precise determination of the position on the sensor 110 at which electromagnetic radiation 118 is incident. This enables the obstruction detection system 100 to determine the exact location on the sensor 110 where electromagnetic radiation 118 emitted by the emission unit 112 is detected. The positional information provided by the x-y indexed pixels may be used to identify the nominal zones 128 and zones 129 on the sensor 110, as described herein. The pixel array may comprise hundreds, thousands, or millions of individual pixels depending on the required detection resolution.

[0123] The sensor module 114 may be implemented as a camera. In this configuration, the optical system 113 may serve as the lens system of the camera, while the sensor 110 may function as the image sensor. The optical system 13 may include various types of optical arrangements to suit different detection requirements.

[0124] The sensor 110, functioning as the image sensor of the camera, may be implemented using various technologies. In some embodiments, the sensor 110 may be a charge-coupled device (CCD) sensor. CCD sensors may offer high sensitivity and low noise, making them suitable for low-light conditions or when detecting faint electromagnetic radiation 118. Alternatively, the sensor 110 may utilise complementary metal -oxide-semiconductor (CMOS) technology. CMOS sensors may provide advantages such as lower power consumption, faster readout speeds, and the ability to integrate additional processing circuitry on the same chip. This integration may allow for on-sensor processing, potentially reducing the computational load on the at least one processor 102, FPGA etc..

[0125] In some implementations, the sensor 110 is a specialised image sensor designed for specific wavelengths, polarisation or radiation types. For instance, if the emission units 112 emit infrared radiation, the sensor 110 can be an infrared-sensitive sensor optimised for detecting that particular range of wavelengths or a particular polarisation.

[0126] The sensor 110 may also vary in resolution and size depending on the specific requirements of the obstruction detection system 100. Higher resolution sensors may provide more detailed information about the detected electromagnetic radiation, potentially allowing for more precise obstruction detection or additional analysis capabilities.

[0127] In some implementations, the obstruction detection system 100 may utilize digital zoom capabilities to allow emitter-detector pairs to operate effectively at different distances. This feature enables a single sensor 110 to adapt to various detection ranges without requiring physical adjustments. For example, the system 100 may employ multiple zoom settings:1. A first zoom setting for short-range detection (0-5m), utilizing the full sensor resolution to provide highly detailed detection in close proximity to the emission unit 112.2. A second zoom setting for medium-range detection (5-10m), where the sensor 110 may digitally zoom to focus on a specific region of interest, maintaining detection accuracy at increased distances.3. A third zoom setting for long-range detection (10-15m), further zooming in to concentrate on a smaller area of the sensor 110, allowing for effective obstruction detection at extended ranges.

[0128] These variable zoom settings may be automatically selected by the at least one processor 102, FPGA etc. based on the known distance between each emission unit 112 and its corresponding sensor module 114. This adaptive approach allows the obstruction detection system 100 to maintain optimal detection capabilities across a wide range of distances, enhancing its flexibility and applicability in various industrial settings.

[0129] The combination of the optical system 113 and the sensor 110 in the sensor module 114 allows for flexible and precise detection of electromagnetic radiation emitted by the emission units 112. This configuration enables the obstruction detection system 100 to adapt to various industrial environments, such as those with ambient light, the presence of dust or smoke, air distortion (e.g. due to heat), vibration etc. and operational requirements.

[0130] The arrangement of multiple emission unit 112 and sensor module 114 pairs allows the obstruction detection system 100 to detect obstructions across one or more planar areas of the environment of the obstruction detection system 100. This configuration provides a more comprehensive detection capability compared to single-point detection systems.

[0131] In operation, the emission units 112 emit electromagnetic radiation 118 towards their corresponding sensor modules 114 (see Figure 23). The electromagnetic radiation 118 travels from each emission unit 112 to its corresponding sensor module 114. The optical system 113 in each sensor module 114 focuses the incoming electromagnetic radiation 118 onto the respective sensor 110.

[0132] The sensor 110 responds to the incident electromagnetic radiation 118 by generating electrical signals at each pixel where the electromagnetic radiation 118 is detected. Each pixel converts the incident electromagnetic radiation 118 into a corresponding electrical signal, with the signal magnitude typically proportional to the intensity of the detected electromagnetic radiation 118. The sensor 110 reads out the electrical signals from the pixels in a sequential or parallel manner. The sensor 110 transmits the electrical signals to the at least one processor 102 via a data interface. This data interface may comprise a digital communication bus or analogue signal lines. The at least one processor 102 receives the electrical signals and processes them to determine the spatial distribution and characteristics of the detected electromagnetic radiation 118 across the sensor 110.

[0133] The obstruction detection system 100 controls the timing and sequence of the emission of electromagnetic radiation 118 from the emission units 112. The obstruction detection system 100 also processes the data from the sensors 110 to determine if an obstruction is present in the detection zone between the emitters 140 and detectors 130.

[0134] The memory 104 stores various types of data related to the operation of the obstruction detection system 100. This data may include calibration information, detection thresholds, historical detection data, and other parameters necessary for the functioning of the system.

[0135] The obstruction detection system 100 operates by emitting electromagnetic radiation 118 from emission units 112 and detecting the electromagnetic radiation 118 using sensor modules 114. Figures 10- 13 illustrate different scenarios under which the obstruction detection system 100 can operate.

[0136] Figure 10 shows an example emission unit 112, sensor module 114 pair of the obstruction detection system 100. As shown in Figure 10, the emission unit 112 emits electromagnetic radiation 118 towards the sensor module 114. The optical system 113 focuses the electromagnetic radiation 118 onto the sensor 110.

[0137] The electromagnetic radiation 118 that travels directly from the emission unit 112 to the sensor module 114 is referred to as propagated electromagnetic radiation 120. The propagated electromagnetic radiation 120 is incident on a specific area of the sensor 110, which is referred to as a nominal zone 128. The nominal zone 128 represents the expected location on the sensor 110 where the propagated electromagnetic radiation 120 is detected when no obstructions are present between the emission unit 112 and the sensor module 114. The nominal zone 128 may be considered an area on the sensor 110. The nominal zone 128 of the sensor 110, at which the propagated electromagnetic radiation is detected, is associated with the physical configuration of the emission unit 112 and the sensor module 114. That is, it is associated with the physical positions of the emitter 140 and the detector 130 of which the emission unit 112 and the sensor module 114 are part of. The nominal zone 128 will be a first zone of the sensor 110 when the emission unit 112 and the sensor module 114 are positioned in first relative positions in which electromagnetic radiation is emitted by the emission unit 112 towards the sensor 110 such that it is incident on the sensor 110 at the first zone of the sensor 110. The nominal zone 128 may be a second, different zone of the sensor 110 (i.e. may be at a different position on the sensor 110) if the emission unit 112 is moved relative to the sensor module 114 and / or the sensor module 114 is moved relative to theemission unit 112. That is, relative movement of the emission unit 112 relative to the sensor module 114, or the sensor module 114 relative to the emission unit 112 may change where the nominal zone 128 on the sensor 110 is.

[0138] Figure 46 shows a close-up view of the sensor 110, which includes a number of pixels 110A. The electromagnetic radiation emitted by the emission unit 112 is detected at a zone on the sensor 110 comprising a plurality of these pixels 110A. The nominal zone 128 can be defined with respect to the pixels of the zone on the sensor 110 at which this electromagnetic radiation is detected. That is, the nominal zone 128 is the area on the sensor 110 at which this electromagnetic radiation is detected.

[0139] Figure 11 again shows an example emission unit 112, sensor module 114 pair of the obstruction detection system 100. In this case, an obstruction 116 is present between the emission unit 112 and the sensor module 114. The obstruction 116 blocks the propagated electromagnetic radiation 120, preventing it from reaching the sensor module 114. That is, the obstruction 116 blocks the electromagnetic radiation emitted by the emission unit 112, thereby preventing it from being incident to the sensor module 114. As a result, the nominal zone 128 on the sensor 110 does not receive the expected electromagnetic radiation 118. That is, the expected electromagnetic radiation is not detected at the nominal zone 128 of the sensor 110. The obstruction detection system 100 detects this absence of electromagnetic radiation 118 in the nominal zone 128 and interprets it as the presence of an obstruction 116.

[0140] Figure 12 demonstrates a scenario where both an obstruction 116 and a mirror 122 are present in the path of the electromagnetic radiation 118 emitted by an emission unit 112. The obstruction 116 blocks the direct path of the propagated electromagnetic radiation 120. However, the mirror 122 reflects a portion of the electromagnetic radiation 118, creating reflected electromagnetic radiation 118A. The reflected electromagnetic radiation 118A bypasses the obstruction 116 and reaches the sensor module 114.

[0141] The reflected electromagnetic radiation 118A is incident on a different area of the sensor 110, referred to as a zone 129. The zone 129 is distinct from the nominal zone 128 where the propagated electromagnetic radiation 120 would typically be detected if no obstruction 116 or mirror 122 were present. Throughout this description, the “zone 129” terminology can be used to indicate a zone on a sensor 110 at which electromagnetic radiation emitted by a corresponding emission unit 112 is detected on the sensor module 110, in cases where that electromagnetic radiation is detected at a position on the sensor 110 that differs from the nominal zone 128. The zone 129, as referred to herein, may alternatively be referred to as an anomalous detection zone 129. The obstruction detection system 100 detects this shift in the location of incident electromagnetic radiation 118 on the sensor 110 from the nominal zone 128 to the zone 129.

[0142] Figure 13 shows the operation of the obstruction detection system 100 with only a mirror 122 present, without any obstruction. In this scenario, both the propagated electromagnetic radiation 120 and the reflected electromagnetic radiation 118A reach the sensor module 114. The propagated electromagnetic radiation 120 is incident on the nominal zone 128 of the sensor 110, while the reflected electromagnetic radiation 118A is incident on the zone 129. That is, the obstruction detection system 100detects the propagated electromagnetic radiation at the nominal zone 128 of the sensor 110, and the reflected electromagnetic radiation 118A at the zone 129 of the sensor 110.

[0143] As described in more detail herein, in use, the obstruction detection system 100 compares the pattern of electromagnetic radiation 118 that is emitted by an emission unit 112 and detected on the sensor 110, in use, to a nominal pattern of in use incident electromagnetic radiation established during a commissioning phase. The nominal pattern includes the identification of one or more nominal zones 128 on the sensor 110 where electromagnetic radiation 118 is expected to be detected under normal operating conditions. When the obstruction detection system 100 detects electromagnetic radiation 118 in zone(s) of the sensor 110 that differ from the nominal zone(s) 128, the obstruction detection system 100 determines that there is a difference between the detected pattern and the nominal pattern. Where there is an appreciable difference, the obstruction detection system 100 can infer that an obstruction 116 or other anomaly is present in the path of the electromagnetic radiation 118 that is emitted by the relevant emission unit 112.

[0144] By continuously comparing subsequently detected electromagnetic radiation 118 to the nominal pattern, the obstruction detection system 100 can reliably detect obstructions 116 and other anomalies in various scenarios, including those involving reflective surfaces like mirrors 122.

[0145] Figures 14, 15, and 16 illustrate variations in emission and detection angles for the obstruction detection system 100. These figures demonstrate how changes in the orientation of the emission unit 112 and sensor module 114 affect the detection of electromagnetic radiation 118 on the sensor 110.

[0146] Figure 14 shows a baseline configuration where the emission unit 112 and sensor module 114 are aligned directly with each other. In other words, the path of transmission of electromagnetic radiation 118 emitted by an emission unit 112 extends from the emission unit 112 to the sensor 110. The emission unit 112 emits electromagnetic radiation 118 towards the sensor module 114. The optical system 113 of the sensor module 114 focuses the incoming electromagnetic radiation 118 onto the sensor 110. In this aligned configuration, the propagated electromagnetic radiation 120 is incident on a specific area of the sensor 110, which, during a commissioning stage, can be set to be the nominal zone 128. In Figure 14, this zone is central on the sensor 110.

[0147] Figure 15 shows a scenario where the emission unit 112 is tilted downward relative to the sensor module 114. That is, the emission unit 112 is misaligned with respect to the sensor module 114. It will be appreciated that while the emission unit 112 is tilted downward relative to the sensor module 114 in Figure 15, the emission unit 112 may be considered to be off-axis with respect to the sensor module 114. That is, the tilt of the emission unit 112 in Figure 15 does not necessarily need to be considered a downward tilt. It can be considered an off-axis tilt in any direction.

[0148] In traditional laser curtains, this misalignment may render the curtain inoperable. However, despite this tilt, the emission unit 112 of the system 100 continues to emit electromagnetic radiation 118 towards the sensor module 114. The optical system 113 still captures and focuses the incoming electromagnetic radiation 118 onto the sensor 110, thus, the system 100 is still operable. However, due to the changed angle of incidence, the location where the electromagnetic radiation 118 is detected on thesensor 110 shifts. This shift results in a new zone on the sensor 110 where the electromagnetic radiation 118 is incident, which differs from the zone shown in the aligned configuration of Figure 14. In this case, a nominal zone 128 can be set at the new zone of the sensor module 110, and the system 100 can still operate, even though the emission unit 112 is misaligned.

[0149] Figure 16 shows a configuration where the sensor module 114 is tilted upward while the emission unit 112 remains in its original position. That is, the sensor module 114 is misaligned with respect to the emission unit 112. It will be appreciated that while the sensor module 114 is tilted upward relative to the emission module 112 in Figure 16, the sensor module 114 may be considered to be off-axis with respect to the emission module 112. That is, the tilt of the sensor module 114 in Figure 16 does not necessarily need to be considered an upward tilt. It can be considered an off-axis tilt in any direction.

[0150] The emission unit 112 emits electromagnetic radiation 118 as before. The tilted sensor module 114, through its optical system 113, still captures the incoming electromagnetic radiation 118. However, the tilt of the sensor module 114 causes another shift in where the electromagnetic radiation 118 is detected on the sensor 110. This results in yet another distinct zone on the sensor 110 where the electromagnetic radiation 118 is incident, different from both the shifted zone of Figure 14 and the shifted zone of Figure 15.

[0151] In practice, it is likely that the emission module 112 or the sensor module 114 of an emission module 112, sensor module 114 pair will be off-axis with respect to the other of the emission module 112, sensor module 114 pair, to some extent, during use. These variations in detection zones on the sensor 110, and the system's 100 ability to dynamically set nominal zones 128, demonstrate the obstruction detection system's 100 ability to adapt to different alignment configurations between an emission unit 112 and the associated sensor module 114. The system 100 accounts for these variations by adjusting the nominal pattern based on environmental conditions. For instance, if the emission unit 112 or sensor module 114 becomes slightly misaligned due to vibration or other environmental factors, the obstruction detection system 100 can recognise this shift in the detected electromagnetic radiation 118 pattern.

[0152] The obstruction detection system 100 may include one or more filtering components. The one or more filtering components may enhance its detection capabilities and reduce interference from unwanted electromagnetic radiation. Figure 20 illustrates a number of examples of these filtering features in detail.

[0153] Referring to Figure 20, in some embodiments, one or more of the emission units 112 emit electromagnetic radiation that is polarised. The electromagnetic radiation may be horizontally polarised. The electromagnetic radiation may be vertically polarised. Further, the emission units 112 can emit electromagnetic radiation of varying wavelengths. For example, one or more emission unit 112 may emit electromagnetic radiation with a wavelength of about 850nm. One or more emission unit may emit electromagnetic radiation with a wavelength of about 940nm. One or more emission unit 112 may emit electromagnetic radiation with a wavelength that is between about 800nm and about lOOOnm. One or more emission unit 112 may emit electromagnetic radiation with a wavelength that is between about 700nm and about 1500nm. In some embodiments, the emission units 112 may inherently emit electromagnetic radiation 118 with a target polarisation or target frequency. For example, laser diodesmay naturally emit linearly polarised electromagnetic radiation 118. Alternatively, the emission units 112 may emit unpolarised or broadband electromagnetic radiation 118, which is then filtered by hardware components to achieve the desired polarisation or frequency characteristics. The emitter 140 may comprise polarising filters positioned in the optical path of the emitted electromagnetic radiation 118 to produce the desired polarisation state. The emitter 140 may comprise optical filters that selectively transmit electromagnetic radiation 118 within a target frequency range whilst blocking other frequencies. In some cases, the emission units 112 may comprise integrated filtering elements that form part of the emission unit 112 structure itself.

[0154] One or more sensor module 114 may include several components designed to fdter and process the incoming electromagnetic radiation. In this way, a particular sensor module 114 may be customised to be better suited for detecting only electromagnetic radiation emitted by the associated emission unit 112.

[0155] Referring to Figure 20, a filter 115 may be positioned at the front of a sensor module 114. That is, a detector 130 may comprise a filter 115. The filter 115 may be an optical filter designed to selectively allow specific wavelengths of electromagnetic radiation to pass through while blocking others. In this configuration, the filter 115 functions as a bandpass filter, allowing only the wavelengths emitted by the corresponding emission unit(s) 112 to reach the sensor 110. This filtering helps to reduce interference from ambient light or other sources of electromagnetic radiation that are not part of the obstruction detection system 100. Thus, it may be said that the detector 130 comprises a filter 115. The filter 115 is associated with the emitter 140 associated with that detector 130. The filter 115 is configured to enable electromagnetic radiation emitted by the associated emitter 140 (i.e. the emitter 140 with one or more emission units 112 that emit electromagnetic radiation at the sensor module 114 of the detector 130) to pass through, and therefore be incident upon, the sensor 110 of the sensor module 114. The filter 115 inhibits the passage of electromagnetic radiation that was not emitted by the associated emitter 140. A characteristic of the filter 115 is associated with the emitter 140. In particular, the characteristic of the filter 115 is a frequency of electromagnetic radiation that the filter 115 permits to pass therethrough.

[0156] Following the filter 115, a polariser 117 is placed in the optical path. The polariser 117 is configured to allow electromagnetic radiation with a specific polarisation to pass through while blocking electromagnetic radiation with other polarisations. This feature enables the obstruction detection system 100 to differentiate between electromagnetic radiation emitted by different emission units 112 based on their polarisation, even if they have the same wavelength. Thus, it may be said that the detector 130 comprises a polariser 117. The polariser 117 is associated with the emitter 140 associated with that detector 130. The polariser 117is configured to enable electromagnetic radiation emitted by the associated emitter 140 (i.e. the emitter 140 with one or more emission units 112 that emit electromagnetic radiation at the sensor module 114 of the detector 130) to pass through, and therefore be incident upon, the sensor 110 of the sensor module 114. The filter 115 inhibits the passage of electromagnetic radiation that was not emitted by the associated emitter 140. A characteristic of the polariser 117is associated with the emitter 140. In particular, the characteristic of the polariser 117 is a polarisation of electromagnetic radiation that the polariser 117 permits to pass therethrough.

[0157] The combination of the filter 115 and the polariser 117 allows the obstruction detection system 100 to selectively detect specific types of electromagnetic radiation. For example, as shown in Figure 20, a first sensor module 114 is configured to detect horizontally polarised 850nm electromagnetic radiation, while a second sensor module 114 is configured to detect vertically polarised 940nm electromagnetic radiation. A third sensor module 114 is configured to detect vertically polarised 850nm electromagnetic radiation. A fourth sensor module 114 is configured to detect horizontally polarised 940nm electromagnetic radiation. This selective detection enhances the system's ability to distinguish between different emission sources and reduces the likelihood of false detections due to stray electromagnetic radiation.

[0158] A detector 130 may comprise a plurality of sensor modules 114, each configured to detect electromagnetic radiation 118 with different characteristics. A first sensor module 114 may be configured to detect electromagnetic radiation 118 having a first wavelength profile and a first polarisation profile. The first wavelength profile may comprise a range of wavelengths or a specific wavelength band, and the first polarisation profile may comprise a specific polarisation state or a range of acceptable polarisation states. A second sensor module 114 may be configured to detect electromagnetic radiation 118 having a second wavelength profile that is different from the first wavelength profile and / or a second polarisation profile that is different from the first polarisation. In some cases, different sensor modules 114 within the same detector 130 may be configured to detect electromagnetic radiation 118 at different wavelengths whilst having the same polarisation sensitivity. Alternatively, different sensor modules 114 may be configured to detect different polarisations of electromagnetic radiation 118 at the same wavelength. The particular combination of wavelength and polarisation characteristics for each sensor module 114 may be selected to enable simultaneous operation of multiple emission unit 112 and sensor module 114 pairs without interference. This configuration enables the obstruction detection system 100 to monitor multiple detection zones simultaneously using different combinations of wavelength and polarisation.

[0159] After the polariser 117, the electromagnetic radiation passes through the optical system 113. The optical system 113 focuses the filtered and polarised electromagnetic radiation onto the sensor 110. The sensor 110 then detects the incident electromagnetic radiation and converts it into electrical signals for processing by the at least one processor 102. In some cases, the filter 115 may form part of the optical system 113. That is, the optical system 113 may comprise the filter 115. The polariser 117 may form part of the optical system 113. That is, the optical system 113 may comprise the polariser 117. In some embodiments, a particular sensor module 114 may only have a filter 115 (i.e. it may not have a polariser 117). Similarly, in some embodiments, a particular sensor module 114 may only have a polariser 117 (i.e. it may not have a filter 115). In some embodiments, neither may be present.

[0160] The use of multiple wavelengths and polarisations in the obstruction detection system 100 provides several advantages. It allows for simultaneous operation of multiple emission unit 112 and sensor module 114 pairs without interference. This configuration can enable an increase in the system's 100 detection speed and resolution, as multiple detection channels operate in parallel. Furthermore, the filtering features improves the operation of the obstruction detection system 100 in a number of differentenvironmental conditions. For example, the system 100 is less susceptible to interference from ambient light sources or reflections that do not match the specific wavelength and polarisation combinations used by the system 100.

[0161] The filtering features also enhance the system's 100 ability to detect and differentiate between various types of obstructions. Different materials interact with electromagnetic radiation differently based on wavelength and polarisation. By using multiple wavelengths and polarisations, the obstruction detection system 100 gathers more information about potential obstructions, which may enable the deployment of more sophisticated detection algorithms.

[0162] In operation, the emission units 112 emit electromagnetic radiation at their respective wavelengths and polarisations. This electromagnetic radiation travels through the detection zone and reaches the detector 130. The filter 115 and polariser 117 in each sensor module 114 ensure that only the intended electromagnetic radiation reaches a respective sensor 110.

[0163] The at least one processor 102 controls the timing and sequencing of the emissions of the emission units 112 and coordinates this with the detection process in the sensor modules 114. By analysing the patterns of detected electromagnetic radiation across different wavelengths and polarisations, the obstruction detection system 100 can provide highly accurate, reliable and high speed obstruction detection.

[0164] Figures 25-32 illustrate a number of physical implementations of the obstruction detection system 100. Figure 25 shows a detector 130 of the obstruction detection system 100. The detector 130 comprises an elongated housing 134. The housing 134 has rounded ends. Inside the housing 134, a detector board 132 is visible. The detector board 132 is a printed circuit board. A number of the electrical components of the detector 130 are mounted to the detector board 132. The detector board 132 contains multiple sensor modules 114. Each sensor module 114 is represented by a circular element representing a lens arrangement with a rectangular component representing a housing of the sensor module 114. The sensor modules 114 are arranged in a linear array along the detector board 132.

[0165] The detector 130 also includes a plurality of planar testing emission units 112A. Each planar testing emission unit 112A is associated with a respective sensor module 114. The planar testing emission units 112 A are used to project electromagnetic radiation onto the face of the sensor 110 in a controlled manner, enabling confirmation that the sensor 110 is operating correctly and does not have appreciable error in its x-y plane detection capabilities, as is described in more detail herein. Each planar testing emission unit 112A is configmed to emit electromagnetic radiation onto a target area of the sensor 110. That is, the pixels of the sensor 110 at which the emitted electromagnetic radiation is defined in the construction of the detector 130. This may, for example, be via a predefined physical position and / or heading of the planar testing emission units 112A, and / or it may be controlled using one or more optical systems (such as a prism, optical fibre etc.). If the sensor 110 indicates detection of the electromagnetic radiation emitted by a planar testing emission unit 112A at a position on the sensor 110 other than that at which the electromagnetic radiation is specifically directed (or intended to be directed), this can indicate either a fault with the planar testing emission unit 112A itself, or an error in the readings being providedby the sensor 110. Remedial action can be taken in such a case. In some cases, the electromagnetic radiation emitted by the planar testing emission units 112A is reflected off an inner surface of a detector cover 136 of the detector 130 prior to being incident to the sensor 110. In some embodiments, the planar testing emission units 112A and associated system 100 functionality may be the same, in one or more aspects, as the planar testing system 146 described in International (PCT) Patent Application No. PCT / AU2024 / 050642, the content of which is hereby incorporated by reference in its entirety. For example, a planar testing emission unit 112A of the obstruction detection system 100 may be the same as, or similar to, in one or more aspects, the planar testing emission units, planar testing emitters 148 and / or planar testing optical systems 150 of International (PCT) Patent Application No. PCT / AU2024 / 050642. The x-y error detection functionality, involving the use of a sensor 110 herein, may be the same as, or similar to, the functionality described in International (PCT) Patent Application No.PCT / AU2024 / 050642 with respect to the sensing system 120 of that document. The detector cover 136 of the present disclosure may provide similar functionality to the window 142 of International (PCT) Patent Application No. PCT / AU2024 / 050642 (e.g. with respect to reflecting electromagnetic radiation emitted by a planar testing emission unit 112A, for detection at a sensor 110).

[0166] Referring to Figure 26, multiple detectors 130 can be arranged to form a detector array. Figure 26 shows multiple detectors 130 arranged in an operating configuration. This operating configuration may be considered a detector array. In this case, the operating configuration is an L-shaped configuration.

[0167] Each detector 130 is connected to another detector 130 at an end thereof. That is, a detector 130 is configured to connect to another detector 130 at the end of that detector 130. In this way, multiple detectors 130 can be linked to form a continuous detection system that can cover different planes or angles. Some detectors 130 are connected to another detector 130 at both longitudinal ends.

[0168] Each detector 130 is configured to connect to another detector 130 at a connection 131. The connection 131 may be a suitable connection, such as a physical connection (e.g. a pivot), a push-fit connection, a snap-fit connection, a magnetic connection, or using an interlocking mechanism. In some cases, the connection 131 may be a flexible joint that allows for adjustable angles between connected detectors 130. The connection 131 may also include electrical contacts to enable signal transmission between connected detectors 130. In some implementations, the connection 131 may comprise a quick-release mechanism that allows for easy assembly and disassembly of the detector array. The connection 131 may comprise a locking mechanism that is configured to enable adjacent detectors 130 to be locked in a particular physical arrangement. The type of connection 131 used may be selected based on the specific requirements of the installation environment and the desired configurability of the obstruction detection system 100.

[0169] Figures 27 and 28 provide more detailed views of the internal components of a detector 130. Figure 27 shows a top perspective view of a detector 130 with the housing 134 hidden. The detector board 132 is visible as an elongated strip. Multiple sensor modules 114 are arranged in a linear array along the detector board 132. Adjacent to each sensor module 114 are the planar testing emission units 112 A.

[0170] Figure 28 provides a section view of the detector 130. The detector 130 is housed within the detector housing 134. A detector cover 136 is positioned at the front of the detector 130. The detector cover 136 may be configured to protect the internal components of the detector 130. The detector cover 136 is at least partially transparent to electromagnetic radiation emitted by an emission unit 112. In some embodiments, the detector cover 136 may comprise the filter(s) 115 and / or the polariser(s) 117 described herein.

[0171] The detector board 132 is mounted inside the detector housing 134. Below the detector board 132 is a detector processor board 138. The detector processor board 138 may comprise processing components for the detector 130.

[0172] Figure 29 shows an example of a physical implementation of an emitter 140 of the obstruction detection system 100. Figure 29 shows a perspective view of a single emitter 140. The emitter 140 comprises an elongated structure with rounded ends. The emitter 140 includes an emitter housing 144. The emitter 140 comprises an emitter cover 146. The emitter cover 146 is mounted to the emitter housing 144. The emitter cover 146 comprises multiple circular elements. These circular elements correspond to individual emission units 112 arranged in a linear array along the length of the emitter 140. That is, each circular element is axially aligned with a respective emission unit 112.

[0173] Referring to Figure 30, multiple emitters 140 can be arranged to form an emitter array. Figure 30 provides a perspective view of multiple emitters 140 arranged in a connected configuration. The connected configuration forms an emitter array. The emitters 140 are connected to form a zigzag pattern, with connections 131 visible at the junction points between the emitters 140.

[0174] Each emitter 140 is connected to another emitter 140 at an end thereof. That is, an emitter 140 is configured to connect to another emitter 140 at the end of that emitter 140. In this way, multiple emitters 140 can be linked to form a continuous emission system that can cover different planes or angles. Each emitter 140 is configured to connect to another emitter 140 at a connection 131. The connection 131 may be a suitable connection, such as a physical connection (e.g. a pivot), a push-fit connection, a snap-fit connection, a magnetic connection, or using an interlocking mechanism. In some cases, the connection 131 may be a flexible joint that allows for adjustable angles between connected emitters 140. The connection 131 may also include electrical contacts to enable signal transmission between connected emitters 140. In some implementations, the connection 131 may be a quick-release mechanism that allows for easy assembly and disassembly of the emitter array. The connection 131 may comprise a locking mechanism that is configured to enable adjacent emitters 140 to be locked in a particular physical arrangement. The type of connection 131 used may be selected based on the specific requirements of the installation environment and the desired configurability of the obstruction detection system 100.

[0175] Figure 31 shows another emitter array comprising multiple connected emitters 140. In particular, Figure 31 illustrates a view of an emitter array comprising three connected emitters 140. Each emitter 140 is connected to another emitter 140 along a longitudinal side thereof. In this case, the connection 131 is at the longitudinal side of the respective emitters 140. It will be appreciated that the detectors 130 may also be connected in such a shaped detector array.

[0176] Figure 32 shows a perspective view of a portion of a detector 130. The housing 134 is hidden in Figure 32. The detector 130 comprises a detector board on which multiple sensor modules 114 are arranged in a grid pattern. Each sensor module 114 is represented by a small circular element. The sensor modules 114 are organised in several rows and columns on the surface of the detector 130. That is, the sensor modules 114 are arranged in a sensor module array.Method 200 for Detecting an Obstruction

[0177] Figure 9 shows a method 200 according to some aspects of the disclosure. The method 200 is a method for detecting an obstruction. The obstruction detection system 100 performs the method 200. The method 200 comprises a commissioning phase. The commissioning phase may be referred to as a commissioning stage. The method 200 comprises an operating phase. The operating phase may be referred to as an operating stage.

[0178] The steps of the commissioning phase are performed at an initial installation of the obstruction detection system 100. The commissioning phase involves energising the emission units 112 and recording commissioning sensor data using the sensor modules 114. No obstructions are present between the emission units 112 and the sensor modules 114 during the commissioning phase. In this phase, the emission units 112 emit electromagnetic radiation, which is detected by the sensors 110 of the corresponding sensor modules 114. The at least one processor 102 samples the sensors 110 to determine the commissioning sensor data and stores this data in the memory 104. Subsequently, the at least one processor 102 determines, for each emission unit 112, sensor module 114 pair, a nominal pattern of the electromagnetic radiation that was emitted by the emission unit 112 and detected by the sensor module 114. The at least one processor 102 determines a nominal pattern for each sensor module 114. That is, the at least one processor 102 determines a nominal pattern for each emission unit 112, sensor module 114 pair. The at least one processor 102 uses the commissioning sensor data to identify one or more nominal zones 128 on the respective sensors 110, where the electromagnetic radiation emitted by the relevant emission unit 112 is detected during the commissioning phase. The at least one processor 102 stores this data in memory 104.

[0179] The operating phase is performed after the commissioning phase has been completed. The operating phase is the phase of the method 200 that the obstruction detection system 100 performs during normal operation. In the operating phase, the at least one processor 102 compares electromagnetic radiation detected by the sensor modules 110 to the nominal pattern. In particular, the at least one processor 102 compares electromagnetic radiation that is emitted by the emitters 140 and detected by the corresponding detectors 130 to the nominal pattern established during the commissioning phase. The at least one processor compares detected electromagnetic radiation at one or more of the sensors 110, to the nominal pattern. The at least one processor 102 identifies one or more zones 129 on the sensor 110 where the subsequently detected electromagnetic radiation that was emitted by the relevant emission unit 112, is incident (if detected) and compares these zones 129 to the one or more nominal zones 128 of the nominal pattern. If the subsequently detected electromagnetic radiation differs from the nominal pattern, the at least one processor 102 generates an obstruction indication output. That is, if the electromagneticradiation emitted by an emitter 112 is detected on the corresponding sensor 110 at a zone 129 of the sensor 110 that differs from the nominal zone 128 identified for that sensor module 114 during the commissioning phase, or is not detected at all, the at least one processor 102 generates an obstruction indication output, as these observations are interpreted to indicate the presence of an obstruction between the relevant emitter 112 and sensor module 114. This obstruction indication output may control the operation of industrial equipment, alert an operator and / or trigger safety measures.

[0180] One or more steps of the method 200 may be repeated continuously during operation of the obstruction detection system 100. The commissioning phase is performed when the system 100 is initially installed, after which, the operating phase is performed on an ongoing basis. Further, the system 100 may use the planar testing emission units 112A to test for x-y error during the operating phase.

[0181] The method 200 described with reference to Figure 9 is described with respect to a particular emission unit 112, sensor module 114 pair of the obstruction detection system 100. ft will be appreciated that one or more steps of the method 200 can be performed for each emission unit 112, sensor module 114 pair of the obstruction detection system 100. The obstruction detection system 100 may cycle through the emission unit 112, sensor module 114 pairs when performing one or more steps of the method 200. For example, the obstruction detection system 100 may perform 202 and 204 for each emission unit 112, sensor module 114 pair, prior to proceeding to 206 and 208 for any emission unit 112, sensor module 114 pair. The obstruction detection system 100 may cycle through emission unit 112, sensor module 114 pairs when performing 202 and 204. Alternatively, the obstruction detection system 100 may perform 202 and 204 contemporaneously for each emission unit 112, sensor module 114 pair, or a plurality of emission unit 112, sensor module 114 pairs. Similarly, the obstruction detection system 100 may perform 206 and 208 for each emission unit 112, sensor module 114 pair. The obstruction detection system 100 may cycle through emission unit 112, sensor module 114 pairs when performing 206 and 208. Alternatively, the obstruction detection system 100 may perform 206 and 208 contemporaneously for each emission unit 112, sensor module 114 pair, or a plurality of emission unit 112, sensor module 114 pairs.

[0182] Prior to commencing the commissioning phase, the emitters 140 and detectors 130 are positioned within the environment that is to be monitored. The emitters 140 and detectors 130 are positioned such that the detection zones between the emitters 140 and detectors 130 cover the areas requiring monitoring. Each emitter 140 is positioned such that the emission units 112 of that emitter 140 are directed towards the corresponding detector 130. Each detector 130 is positioned such that the sensor modules 114 of that detector 130 are directed towards the corresponding emitter 140. The emission units 112 and associated sensor modules 114 are aligned such that electromagnetic radiation 118 emitted by the emission units 112 will be incident upon the sensors 110 of the corresponding sensor modules 114. This alignment need not be precise, as the obstruction detection system 100 is configured to accommodate some misalignment between emission units 112 and sensor modules 114, as described herein. Once the emitters 140 and detectors 130 are positioned and the emission units 112 and sensor modules 114 are sufficiently aligned, the commissioning phase may commence.

[0183] Referring to Figure 9, at 202, the obstruction detection system 100 records commissioning sensor data. The obstruction detection system 100 records the commissioning sensor data using the sensor module 114. The obstruction detection system 100 records the commissioning sensor data during the commissioning phase of operation. The recorded commissioning sensor data is associated with the sensor unit 114 for which it is recorded. That is, it will be appreciated that the commissioning sensor data for each sensor unit 114 can be different.

[0184] At 202, the emission unit 112 emits electromagnetic radiation, which is detected by the sensor 110 of the sensor module 114. In particular, the sensor 110 of the sensor module 114 that is associated with the activated emission unit 112 (i.e. the sensor module 114 of the emission unit 112, sensor module 114 pari) detects electromagnetic radiation emitted by the activated emission unit 112. The obstruction detection system 100 controls the emission unit 112 to emit the electromagnetic radiation. For example, the at least one processor 102 may activate the emission unit 112, such that the emission unit 112 emits electromagnetic radiation. The obstruction detection system 100 samples the sensor 110 to determine the commissioning sensor data and stores this data in the memory 104. The at least one processor 102 may sample the sensor 110 to determine the commissioning sensor data. This may involve the at least one processor 102 sending control signals to the sensor 110 to initiate a readout sequence, during which the pixel values are transferred from the sensor 110 to the at least one processor 102 for processing and storage. The at least one processor 102 may store the commissioning sensor data in memory 104.The commissioning sensor data may include sensor data representing the spatial distribution and intensity of electromagnetic radiation incident on the sensor 110 of the relevant sensor module 114 at a specific time or over a specific time interval. This specific time interval may be referred to as an imaging window during which the sensor 110 integrates the incident electromagnetic radiation 118. This electromagnetic radiation can include that which was emitted by the emission unit 112. In some aspects, the data may comprise image data captured by the sensor 110, providing a visual representation of the electromagnetic radiation pattern detected by each sensor module 114.

[0185] For the purposes of this disclosure, recording the commissioning sensor data may involve capturing, storing, and / or digitising the readings taken using the sensor 110, which may include raw sensor output, processed data, or derived measurements from the sensor 110. In some cases, recording may also encompass logging metadata such as timestamps, sensor identifiers, or environmental conditions associated with the captured data.

[0186] It can be appreciated that at 202, the at least one processor 102 performs an emission operation and a detection operation. The at least one processor 102 performs the emission operation by activating the emission unit 112 to emit electromagnetic radiation 118. The at least one processor 102 controls the emission unit 112 to emit the electromagnetic radiation 118 towards the corresponding sensor module 114. The at least one processor 102 performs the detection operation by controlling the sensor 110 to detect the electromagnetic radiation 118 emitted by the emission unit 112. The detection operation comprises reading out electrical signals from the pixels of the sensor 110. The at least one processor 102 samples the sensor 110 during the detection operation to obtain the commissioning sensor data. Thecommissioning sensor data represents the spatial distribution and intensity of electromagnetic radiation 118 detected by the sensor 110 during the detection operation. The at least one processor 102 stores the commissioning sensor data in the memory 104. The emission operation and the detection operation may be performed sequentially or with temporal overlap such that the sensor 110 detects electromagnetic radiation 118 whilst the emission unit 112 is emitting.

[0187] At 204, the obstruction detection system 100 determines a nominal pattern of electromagnetic radiation that is emitted by the emission unit 112 and detected by the sensor module 114 during the commissioning phase. The nominal pattern comprises information characterising the electromagnetic radiation 118 that was emitted by the emission unit 112 and detected by the sensor 110 during the commissioning phase. The nominal pattern may include the identification of one or more nominal zones 128 on the sensor 110 where the electromagnetic radiation 118 was detected. The nominal pattern may include intensity information indicating the intensity of electromagnetic radiation 118 detected at each nominal zone 128. The nominal pattern may include spatial distribution information describing how the electromagnetic radiation 118 is distributed across the sensor 110. The nominal pattern may include timing information relating to when the electromagnetic radiation 118 was detected during the commissioning phase. The nominal pattern may include wavelength or colour information characterising the spectral properties of the detected electromagnetic radiation 118. The nominal pattern may include polarisation information describing the polarisation state of the detected electromagnetic radiation 118. The nominal pattern serves as a reference against which subsequently detected electromagnetic radiation 118 is compared during the operating phase. The nominal pattern represents the expected characteristics and distribution of electromagnetic radiation 118 on the sensor 110 when no obstruction is present between the emission unit 112 and the sensor module 114. The obstruction detection system 100 therefore uses the commissioning sensor data to identify one or more nominal zones 128 on the sensor 110 where the electromagnetic radiation that was emitted by the emission unit 112 is detected.

[0188] The obstruction detection system 100 may perform a number of operations to identify the one or more nominal zones 128 on the sensor 110 based on the commissioning sensor data. For example, the obstruction detection system 100 may examine the spatial distribution of detected electromagnetic radiation across the sensor's 110 surface, as recorded in the commissioning sensor data. This analysis may involve identifying areas of peak intensity. An area of peak intensity is likely to correspond to an area at which electromagnetic radiation emitted by the emission unit 112 is being detected. Alternatively, the obstruction detection system 100 may establish an intensity threshold, and pixels detecting electromagnetic radiation 118 with intensity above this threshold may be classified as part of the nominal zone 128. The obstruction detection system 100 may identify regions where the intensity exceeds a percentage of the maximum detected intensity, such as 50% or 80% of the peak intensity. The obstruction detection system 100 may use adaptive thresholding techniques that account for variations in background electromagnetic radiation levels across different regions of the sensor 110.

[0189] A nominal zone 128 on the sensor 110 is a defined group of pixels that indicates a region where electromagnetic radiation 118 emitted by the emission unit 112 is expected to be detected during normal,unobstructed operation. Each nominal zone 128 may be classified by the x-y coordinates of the pixels that comprise that nominal zone 128. The x-y coordinates of these pixels define the spatial extent and position of the nominal zone 128 on the sensor 110. The obstruction detection system 100 may store the x-y coordinates of the pixels comprising each nominal zone 128 in the memory 104 as part of the nominal pattern. A nominal zone 128 may be contiguous, comprising adjacent pixels, or may comprise multiple separate regions on the sensor 110. The identification of the nominal zone 128 enables the obstruction detection system 100 to determine the expected location on the sensor 110 where electromagnetic radiation 118 from the emission unit 112 should be detected when no obstruction is present.

[0190] In some embodiments, the obstruction detection system 100 may perform one or more image processing technique to analyse the commissioning sensor data. These techniques may include edge detection, blob analysis, or pattern recognition algorithms to identify distinct regions on the sensor 110 where electromagnetic radiation is consistently detected during the commissioning phase, as indicated by the commissioning sensor data.

[0191] The obstruction detection system 100 may also consider the intensity levels of detected electromagnetic radiation, establishing thresholds or ranges that define the nominal zones 128. In some cases, the obstruction detection system 100 may create a heat map or intensity profile of the sensor 110 surface based on the commissioning data, and use this to delineate the boundaries of nominal zones 128. The processor 102 may take into account variations in detected intensity over time, using statistical methods to determine average intensity levels and acceptable deviations within each nominal zone 128.

[0192] In some embodiments, the obstruction detection system 100 may use machine learning algorithms trained on commissioning sensor data to identify and characterise the nominal zones 128. These algorithms may be capable of recognising complex patterns or subtle variations in the detected electromagnetic radiation that define the nominal zones 128. The obstruction detection system 100 may employ edge detection algorithms to identify the boundaries of nominal zones 128 by detecting abrupt changes in intensity or color within the commissioning sensor data. These algorithms can highlight the transition areas between regions of high and low electromagnetic radiation 118 detection, effectively outlining the nominal zones 128. The detection and processing of electromagnetic radiation 118 patterns may be implemented using software-based solutions running on the processor 102. Alternatively, the detection and processing of electromagnetic radiation 118 patterns may be implemented through hardware-based approaches. A hardware approach may use at least one of field programmable gate arrays (FPGAs), programmable logic devices (PLDs), or dedicated logic blocks. Hardware-based implementations may offer faster processing speeds and lower latency, which can improve the response time of obstruction detection in high-speed industrial environments.

[0193] The obstruction detection system 100 stores the nominal pattern for the sensor module 114 in memory 104. This may comprise storing the identified nominal zone(s) 128 in memory 104. The nominal pattern may comprise the x-y coordinates of pixels that define the nominal zone(s) 128. The nominal pattern may comprise intensity values or intensity ranges associated with the nominal zone(s) 128. The nominal pattern may comprise spatial distribution information describing the shape, size, or geometricproperties of the nominal zone(s) 128. The nominal pattern may comprise wavelength or spectral characteristics of the electromagnetic radiation 118 detected at the nominal zone(s) 128. The nominal pattern may comprise polarisation information describing the polarisation state of the electromagnetic radiation 118 detected at the nominal zone(s) 128. The nominal pattern may comprise temporal characteristics such as pulse timing or modulation patterns of the detected electromagnetic radiation 118. The nominal pattern may comprise statistical information such as mean intensity, standard deviation, or variance of the detected electromagnetic radiation 118 within the nominal zone(s) 128. This may comprise storing the identified nominal zone(s) 128 in memory 104.

[0194] The commissioning phase of the method 200 comprises steps 202 and 204.

[0195] Following completion of the commissioning phase during which 202 and 204 are performed (in some cases, for each emission unit 112, sensor module 114 pair), the obstruction detection system 100 commences the operating phase. The operating phase includes steps 206 and 208. During the operating phase, the sensor modules 114 monitor electromagnetic radiation emitted by the corresponding emission units 112, and the obstruction detection system 100 processes the data generated by the sensor modules 114 to look for obstructions in the space between the sensor modules 114 and the emission units 112. This electromagnetic radiation that is monitored, which may comprise ambient electromagnetic radiation and / or electromagnetic radiation emitted by one or more emission unit 112 during the operating phase, may be referred to as subsequently detected electromagnetic radiation.

[0196] At 206, the obstruction detection system 100 compares subsequently detected electromagnetic radiation to the nominal pattern. Specifically, the obstruction detection system 100 compares zones 129 on the sensor module 110 at which the electromagnetic radiation emitted by the emitter 112 is detected to the respective nominal zone 128. Where no obstruction is present between the emitter 112 and the sensor module 114, the electromagnetic radiation emitted by the emitter 112 will be detected at the sensor 110 within the nominal zone 128. This is considered a normal, or unobstructed operating condition.

[0197] The subsequently detected electromagnetic radiation might differ from the nominal pattern in several ways. In some cases, the intensity of the electromagnetic radiation emitted by an emission unit 112 that is detected may be significantly lower than expected, or entirely absent. This can be interpreted as indicating that an obstruction is blocking or partially blocking the path between the emission unit 112 and the sensor module 114. Alternatively, the spatial distribution of the detected radiation on the sensor 110 may deviate from the nominal zones 128, suggesting that the radiation is being reflected or refracted by an obstruction. In other instances, the timing or frequency of the detected radiation pulses may differ from the expected pattern, potentially indicating intermittent obstructions or issues with the emission units 112.

[0198] At 206, the obstruction detection system 100 controls the emission units 112 to emit electromagnetic radiation. The at least one processor 102 activates an emission unit 112 such that the emission unit 112 emits electromagnetic radiation. As mentioned with respect to the commissioning phase, during normal operation, this emitted electromagnetic radiation is directed towards the corresponding sensor module 114. This electromagnetic radiation is directed towards the correspondingsensor module 114 and detected by the sensor module 114. The frequency of emission and detection may be adjusted based on the specific application requirements, ranging from continuous monitoring to periodic checks. The specific location of detection of the electromagnetic radiation, on the sensor 110 of the sensor module 114 is processed to enable information about the environment of the system 100 to be inferred.

[0199] Specifically, the subsequently detected electromagnetic radiation is compared to the nominal pattern that was determined at 204 for the respective sensor module 114. The obstmction detection system 100 identifies one or more zones 129 on the sensor 110 where the subsequently detected electromagnetic radiation that includes electromagnetic radiation emitted by the relevant emission unit 112 is incident on the sensor 110 and compares these zones 129 to the one or more nominal zones 128 of the nominal pattern for that sensor module 114.

[0200] As the sensor module 114 detects electromagnetic radiation, the obstruction detection system 100 continuously processes the data generated by the sensor 110. The obstruction detection system 100 identifies the zones 129 where the emitted electromagnetic radiation is incident on the sensor 110. This identification process may involve similar techniques to those used in determining the nominal zones 128, such as intensity analysis or pattern recognition algorithms. This identification process may involve similar techniques to those used in determining the nominal zones 128, such as intensity analysis or pattern recognition algorithms. The obstruction detection system 100 may analyse the intensity distribution across the sensor 110 to identify pixels where electromagnetic radiation 118 above a threshold intensity is detected. The obstruction detection system 100 may identify contiguous regions of pixels detecting electromagnetic radiation 118 and classify these regions as zones f29. The obstruction detection system iOO may apply edge detection algorithms to identify the boundaries of zones f29 where electromagnetic radiation 118 is detected. The obstruction detection system 100 may use blob detection techniques to identify distinct regions of detected electromagnetic radiation 118 on the sensor 110. The obstruction detection system 100 may analyse the spatial distribution, shape, and size of detected electromagnetic radiation 118 to characterise the zones 129. The obstruction detection system 100 may filter the detected electromagnetic radiation 118 based on wavelength, polarisation, or temporal characteristics to isolate electromagnetic radiation 118 emitted by the emission unit 112 from ambient electromagnetic radiation.

[0201] The obstruction detection system 100 then compares the identified zones 129 to the nominal zones 128 of the nominal pattern. This comparison may involve analysing a measurable difference between the identified zone(s) 129 and the nominal zone(s). This measurable difference may be in the form of a spatial difference (i.e. a difference in position on the sensor 110 between the nominal zone(s) 128 and the zone(s) 129, an intensity difference, or another characteristic of the detected radiation in relation to the expected pattern.

[0202] The spatial difference may comprise a positional offset between the centroid of the zone(s) 129 and the centroid of the nominal zone(s) 128. The spatial difference may comprise a difference in the x-y coordinates of pixels comprising the zone(s) 129 compared to the x-y coordinates of pixels comprisingthe nominal zone(s) 128. The spatial difference may be quantified as a distance measurement between corresponding points in the zone(s) 129 and the nominal zone(s) 128.

[0203] The intensity difference may comprise a difference between the peak intensity detected in the zone(s) 129 and the peak intensity recorded in the nominal zone(s) 128. The intensity difference may comprise a difference in the average intensity across the zone(s) 129 compared to the average intensity across the nominal zone(s) 128. The intensity difference may comprise a comparison of intensity distributions or intensity profiles between the zone(s) 129 and the nominal zone(s) 128.

[0204] The shape difference may comprise a comparison of the geometric properties of the zone(s) 129 and the nominal zone(s) 128, such as circularity, aspect ratio, or perimeter-to-area ratio. The size difference may comprise a comparison of the total number of pixels in the zone(s) 129 compared to the total number of pixels in the nominal zone(s) 128. The size difference may comprise a comparison of the surface area of the zone(s) 129 to the surface area of the nominal zone(s) 128.

[0205] The at least one processor 102 may calculate a weighted average position of the detected electromagnetic radiation 118 within the zone(s) 129. The at least one processor 102 calculates the weighted average position by weighting each pixel’s x-y coordinates by its detected intensity, such that brighter pixels contribute more to the calculated position than dimmer pixels. This weighted average position may represent the centroid of the bright spot detected on the sensor 110. The at least one processor 102 compares the weighted average position of the zone(s) 129 to a weighted average position of the nominal zone(s) 128 that was determined during the commissioning phase. The at least one processor 102 determines a positional deviation based on the comparison between the weighted average position of the zone(s) 129 and the weighted average position of the nominal zone(s) 128. If the positional deviation exceeds a threshold value, the at least one processor 102 determines that the subsequently detected electromagnetic radiation 118 differs from the nominal pattern, indicating a potential obstruction.

[0206] The at least one processor 102 may use predefined thresholds or statistical methods to determine if there is a significant deviation from the nominal pattern. The at least one processor 102 may compare the measurable difference to a threshold value, and determine that a significant deviation exists when the measurable difference exceeds the threshold value. The at least one processor 102 may use statistical measures such as standard deviation, variance, or correlation coefficients to quantify the similarity between the zone(s) 129 and the nominal zone(s) 128. The at least one processor 102 may employ pattern matching algorithms or machine learning models trained to recognise deviations from the nominal pattern..

[0207] If the detected radiation pattern matches the nominal pattern within acceptable limits, the system 100 continues normal operation. However, if a deviation is detected that exceeds the defined thresholds, the system 100 proceeds to generate an obstruction indication output as described at 208.

[0208] The at least one processor 102 may calculate a similarity metric that quantifies the degree of similarity between the zone(s) 129 and the nominal zone(s) 128. The similarity metric may be a numerical value that represents how closely the subsequently detected electromagnetic radiation 118 matches thenominal pattern. The similarity metric may be calculated based on one or more of the measurable differences described herein, such as spatial difference, intensity difference, shape difference, or size difference.

[0209] In some cases, the similarity metric may be an overlap coefficient that represents the proportion of pixels that are common to both the zone(s) 129 and the nominal zone(s) 128. The similarity metric may be a correlation coefficient that measures the statistical correlation between the intensity values in the zone(s) 129 and the intensity values in the nominal zone(s) 128. The similarity metric may be a distance metric, such as Euclidean distance, calculated between feature vectors representing the zone(s) 129 and the nominal zone(s) 128.

[0210] The at least one processor 102 compares the similarity metric to a similarity threshold. If the similarity metric indicates that the detected radiation pattern matches the nominal pattern within acceptable limits (for example, if the similarity metric exceeds the similarity threshold), the system 100 continues normal operation. If the similarity metric indicates a deviation that exceeds the defined thresholds (for example, if the similarity metric falls below the similarity threshold), the system 100 proceeds to generate an obstruction indication output as described at 208.

[0211] Throughout this process, the system 100 may also account for variations in ambient electromagnetic radiation. This could involve periodically updating baseline measurements or using filtering techniques to isolate the emitted radiation from background noise, ensuring accurate obstruction detection even in changing environmental conditions.

[0212] The obstruction detection system 100 performs 206 for each emission unit 112 and sensor module 114 pair during normal operation. The obstruction detection system 100 may perform step 206 for all emission unit 112 and sensor module 114 pairs contemporaneously, such that electromagnetic radiation 118 is emitted by multiple emission units 112 simultaneously and detected by the corresponding sensor modules 114 simultaneously. Alternatively, the obstruction detection system 100 may perform step 206 sequentially for each emission unit 112 and sensor module 114 pair, cycling through the pairs one at a time. In some cases, the obstruction detection system 100 may perform step 206 for groups of emission unit 112 and sensor module 114 pairs, where each group comprises a subset of the total number of pairs. The at least one processor 102 may control the timing and sequencing of the emission operations and detection operations for the emission unit 112 and sensor module 114 pairs to avoid interference between pairs and to optimise the detection speed, reaction time, and efficiency of the obstruction detection system 100. The reaction time may refer to the time interval between detection of an obstruction and generation of the obstruction indication output, which may be minimised through appropriate timing and sequencing of emission and detection operations.

[0213] At 208, the obstruction detection system 100 generates an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern. The at least one processor 102 may generate the obstruction indication output. The obstruction indication output may be used to, or may, control the operation of an apparatus or trigger operational measures associated with the industrial facility. As described herein, the output may control a value of an operating parameterof an apparatus. The apparatus may be a machine of the industrial facility, the operating parameter of the machine influencing an aspect of operation of the machine.

[0214] The obstruction indication output generated by the obstruction detection system 100 may be configured to change a value of an operating parameter of an apparatus. In some cases, this change may involve adjusting the speed, position, or operational state of the apparatus. For example, the obstruction indication output may trigger a reduction in the speed of moving components, initiate a controlled stop sequence, or alter the trajectory of robotic arms. The specific parameter changes will depend on the nature of the detected obstruction and the particular requirements of the industrial setting in which the obstruction detection system 100 is deployed.

[0215] In some cases, the obstruction indication output may be used to log events for later analysis or to notify remote monitoring systems. This could involve sending data about the nature and timing of the detected obstruction to a central control system or initiating a diagnostic routine to check the integrity of the obstruction detection system 100 itself. The subsequently detected electromagnetic radiation incident the sensor 110 may be stored in memory 104 as operating image data. The operating image data can comprise an image taken using the sensor 110 at each of a plurality of times during the operating phase. Each image can be reviewed or played back at a later point in time, as part of an analysis of the operation of the obstruction detection system 100. This review can be performed for a single sensor module 114, or all sensor modules 114 simultaneously.

[0216] Figure 21 illustrates a timing diagram that relates to the method 200, showing how the obstruction detection system 100 may use staggered integration times for multiple sensor modules 114. The diagram shows the activation times for three emission units 112 (labelled as Lasers 1, 2, and 3) and the corresponding integration times for three sensor modules 114 (labelled as Cameras 1, 2, and 3).

[0217] The emission units 112 are activated sequentially, with each emission unit 112 emitting electromagnetic radiation for a short duration. The sensor modules 114 have staggered integration times that align with the activation of their corresponding emission units 112. This staggered timing allows the obstruction detection system 100 to efficiently detect electromagnetic radiation from multiple emission units 112 without interference.

[0218] For example, when Laser 1 (an emission unit 112) is activated, Camera 1 (a sensor module 114) integrates the detected electromagnetic radiation. This is followed by the activation of Laser 2 and the integration period of Camera 2, and then Laser 3 and Camera 3. This sequence repeats continuously during operation.

[0219] The staggered integration times enhance the efficiency of the method 200 by allowing the obstruction detection system 100 to process data from multiple sensor modules 114 in parallel. This approach increases the overall detection speed and resolution of the system 100. This staggered approach can be taken for emissions and detections performed both during the commissioning phase and the operating phase.

[0220] Figure 42 shows a number of plan views of the face of the sensor 110 of a sensor module 114, and where incident electromagnetic radiation emitted by the corresponding emission unit 112 is detectedat various stages of the method 200. The left three instances of the sensor 110 in Figure 42 show where incident electromagnetic radiation emitted by the corresponding emission unit 112 is detected during the commissioning phase (left-most sensor 110 in Figure 42), and how this is translated into a nominal zone 128 (middle and right-most sensors 110 in Figure 42). The circle on the left-most sensor 110 face of these three shows where the propagated electromagnetic radiation 120 from the emission unit 112 is incident the sensor 110. The middle of the three sensor 110 faces shows a circle corresponding to where, on the sensor 110, the nominal zone 128 is defined. The right-most figure of the three sensor faces 110 shows the nominal zone 128 on the sensor 110, without the presence of the propagated electromagnetic radiation 120.

[0221] The right four instances of the sensor 110 in Figure 42 show representations of the face of the sensor 110 during a number of different operating scenarios during the operating phase. The left-most sensor 110 face shows a normal operating case where no obstruction is present, and the boundary 128 of the nominal zone 128 is overlayed on the sensor 110. This is the case of Figure 10. In this case, the incident electromagnetic radiation emitted by the corresponding emission unit 112 is detected within the nominal zone 128. The sensor 110 face of this group of four, that is second from the left, shows a case where an obstruction is blocking the propagated electromagnetic radiation 120 emitted by the corresponding emission unit 112. In this case, no electromagnetic radiation emitted by the corresponding emission unit 112 is detected at the sensor 110. This is the case of Figure 11. The sensor 110 face second from the right of this group of four shows a case where electromagnetic radiation 129 that was emitted by the emission unit 112 is reflected (e.g. from a nearby mirror, glass panel, prism etc.) and detected at the sensor 110. As shown in Figure 42, this reflected electromagnetic radiation 129 is detected at least partially outside the nominal zone 128. This is the case of Figure 12. The right-most sensor 110 face of this group of four shows a case where both the propagated electromagnetic radiation 120 is unobstructed, and therefore detected at the sensor 110 within the nominal zone 128, along with the reflected electromagnetic radiation (e.g. that is emitted by the emission unit 112 and reflected off a mirror, glass panel, prism etc.). This is the case of Figure 13.

[0222] Figure 43 shows a series of frames of the face of a sensor 110 during a subsequent use of the obstruction detection system 100, after it has already been commissioned. In this case, the obstruction detection system 100 is powered up, and the nominal zone 128 has already been determined. In this case, the obstruction detection system 100 proceeds straight to the operating phase, as indicated by the three sensor 110 frames to the right side of the figure.

[0223] Over time, the position on the sensor 110 at which electromagnetic radiation emitted by the emission unit 112 is detected by the corresponding sensor module 114 may drift. This can be due to movements of the emission unit 112 or sensor module 114, environmental changes such as air temperature etc. In such cases, the commissioning phase can be re-performed, and a new nominal zone 128 and nominal pattern can be identified and stored for use during subsequent operating phases, as is shown in Figure 44.

[0224] As described herein, the commissioning phase is initially performed, following which the operating phase is performed. The obstruction detection system 100 may intermittently re-perform the commissioning phase during use to accommodate for in-use movement of emitters 140 or detectors 130. The obstruction detection system 100 may re-perform the commissioning phase to accommodate for changes in environmental characteristics, such as temperature, humidity, or vibration, that may result in a change in the position of the nominal zones 128. Re-performing the commissioning phase enables the obstruction detection system 100 to update the nominal pattern to reflect the current physical configuration and environmental conditions. The at least one processor 102 may automatically initiate a re-commissioning phase based on detected changes in the detected electromagnetic radiation patterns, elapsed time since the last commissioning phase, or in response to a user command. This may be a manual operation, in some embodiments. Following re-commissioning, the obstruction detection system 100 can resumes the operating phase using the updated nominal pattern.Examples of Commissioning Sensor Data

[0225] As described herein, the obstruction detection system 100 records and analyses data to establish baseline patterns and detect obstructions. Figures 18 and 19 illustrate examples of data recorded during the commissioning phase.

[0226] Figure 18 shows two graphical representations of commissioning sensor data obtained using respective sensor modules 114 during the commissioning phase. The left portion of Figure 18 shows a graphical representation of commissioning sensor data obtained using a first sensor module 114. The position at which the propagated electromagnetic radiation 120 emitted by the relevant emission unit 112 is incident to the sensor 110 of the sensor module 114 is indicated at 120. This zone of the sensor 110 is set as the nominal zone 128 of that sensor module 114.

[0227] The right portion of Figure 18 shows another graphical representation of commissioning sensor data obtained using a second sensor module 114. The position at which the propagated electromagnetic radiation 120 emitted by the relevant emission unit 112 is incident to the sensor 110 of the sensor module 114 is indicated at 120. This zone of the sensor 110 is set as the nominal zone 128 of that sensor module 114.

[0228] The graphical representations of commissioning sensor data provide visual information about the patterns of electromagnetic radiation detected by each sensor module 114 during the commissioning phase. The nominal zones 128 identified in these representations serve as reference points for subsequent obstruction detection. As can be seen, the nominal zone 128 of the sensor 110 of a first sensor module 114 may be at a different position (e.g. with reference to x and y indexes of the sensor 110) to the nominal zone 128 of the sensor 110 of a second sensor module 114.

[0229] Figure 19 illustrates a more detailed graphical representation of commissioning sensor data obtained from two sensor modules 114. The image is displayed within an image window, which is part of an image processing software interface.

[0230] The image window contains two side-by-side images, each representing data from a separate sensor module 114. Both images show a cone-like pattern of light intensity, with the brightest areasappearing as white regions against a darker background. This pattern visualises how the electromagnetic radiation is distributed across the sensor 110 of each sensor module 114.

[0231] In each image of Figure 19, the position at which the propagated electromagnetic radiation 120 is incident to the sensor 110 is indicated by a circle. These points represent where the electromagnetic radiation is incident on the respective sensor modules 114 during the commissioning phase. The nominal zones 128 for each sensor module 114 are denoted by the circles.

[0232] During the commissioning phase, the obstruction detection system 100 records commissioning sensor data for each sensor module 114. This process involves activating the emission units 112 to emit electromagnetic radiation and capturing the resulting patterns detected by the corresponding sensor modules 114. The system 100 may record multiple data points for each sensor module 114 to account for potential variations in the emission and detection of electromagnetic radiation.

[0233] The obstruction detection system 100 analyses the recorded commissioning sensor data to determine a nominal pattern of electromagnetic radiation for each sensor module 114. This nominal pattern can include information about the expected intensity, distribution, and location of detected electromagnetic radiation on the sensor 110 when no obstructions are present.

[0234] The nominal pattern for each sensor module 114 is stored in the memory 104 of the obstruction detection system 100. This stored information serves as a reference for subsequent obstruction detection operations.Selectively Using Sensor Modules 114

[0235] The obstruction detection system 100 is applied to control industrial equipment, as illustrated in Figures 33-40. Figure 33 shows an emitter 140 installed on an apparatus 150. The emitter 140 is a cylindrical device with a circular face including multiple small circular elements arranged in a grid pattern, each being associated with a respective emission unit 112 that is beneath the circular face. The emitter 140 is housed within a circular opening in a wall of the apparatus 150. It will be appreciated that the particular shape of an emitter 140 and / or a detector 130 can be customised to a particular application.

[0236] Figures 34-40 illustrate the application of the obstruction detection system 100 in a specific type of industrial machine, a folding machine. In this case, the folding machine may be considered an apparatus 150. The apparatus 150 includes a movable component 152, which is monitored by the obstruction detection system 100 comprising an emitter 140 and a detector 130 as described herein. While described in the context of a folding machine herein, it will be understood that similar or the same concepts would apply to other machinery, such as press brakes.

[0237] In Figure 34, the emitter 140 is positioned on the left side of the apparatus 150, while the detector 130 is located on the right side (it will be appreciated that these sides may be inverted in some cases). That is, the emitter 140 is located on a first side of the apparatus 150 and the detector 130 is located on a second side of the apparatus 150. The emitter 140 emits electromagnetic radiation which is detected by the detector 130. The movable component 152 of the apparatus 150 is positioned above the path of the emitted electromagnetic radiation. That is, the moveable component 152 is located beyond the path of the emitted electromagnetic radiation.

[0238] Figure 35 provides a side, sectional view of this apparatus 150, with the emitter 140 shown. The movable component 152 is depicted as an elongated element extending upwards. The obstruction detection system 100 can selectively disregard certain emission units 112 and sensor modules 114 to accommodate expected movements of the apparatus 150, in use. By identifying dynamic exclusion zones corresponding to the apparatus's 152 expected movement path, the processor 102 can avoid generating false alarms while maintaining detection capabilities in other areas. This approach allows the system 100 to operate effectively in dynamic industrial environments. The process of identifying or defining a dynamic exclusion zone and disregarding the emission units 112 and sensor modules 114 of that zone may be referred to as muting that portion of the obstruction detection system 100.

[0239] Figures 36 and 37 demonstrate how the obstruction detection system 100 adapts to different positions of the movable component 152 during operation of the apparatus 150. In Figure 36, the movable component 152 is in an intermediate position, with a gap between it and the lower part of the apparatus 150. In this position, the emitter 140 has a mostly unobstmcted line of sight across the work area of the folding machine, however, a portion of the emitter's 140 line of sight with the detector 130 is obstructed by the movable component 152.

[0240] Figure 37 shows the movable component 152 in a lowered position, closer to the lower part of the industrial machinery 150. In this configuration, the movable component 152 again partially obstmcts the emitter 140, with the partial obstruction larger than that of Figure 36.

[0241] The obstruction detection system 100 is designed to handle these changing positions of the movable component 152 without generating false alarms. The obstruction detection system 100 identifies regions of the emitter 140 (which may involve the identification of one or more emission units 112) and / or the detector 130 (which may involve the identification of one or more sensor modules 114) that correspond to the expected movement path of the movable component 152 during normal operation of the apparatus 150. These identified regions are designated as dynamic exclusion zones of the obstruction detection system 100. That is, the obstruction detection system 100 may designate these emission units 112 and / or sensor modules 114 as dynamically excluded components.

[0242] When comparing subsequently detected electromagnetic radiation to the nominal pattern, the obstruction detection system 100 selectively disregards electromagnetic radiation detected, or not detected, within these dynamic exclusion zones. That is, the obstruction detection system 100 selectively ignores the sensor units 114 of the dynamic exclusion zone(s). This selective disregarding avoids false obstruction indications due to the expected movement of the movable component 152.

[0243] For example, as the movable component 152 moves from the position shown in Figure 35 to the position shown in Figure 37, certain emission units 112 of the emitter 140 and sensor modules 114 of the detector 130 are progressively obstructed. The obstruction detection system 100 anticipates this obstruction based on the identified dynamic exclusion zones and does not generate an obstruction indication output in response to this expected change in the detected electromagnetic radiation.

[0244] When the obstruction detection system 100 detects an unexpected obstruction (one that occurs outside the dynamic exclusion zones or in an unexpected manner) the obstruction detection system 100generates the obstruction indication output. This output is configured to change an operating parameter of the apparatus 150. The obstruction detection system 100 detects the unexpected obstruction by comparing subsequently detected electromagnetic radiation to the nominal pattern, as described with reference to step 206 of the method 200. The obstmction detection system 100 identifies zones 129 on the sensor 110 where electromagnetic radiation 118 is detected and compares these zones 129 to the nominal zones 128. When the zones 129 differ from the nominal zones 128 by more than a threshold amount, or when electromagnetic radiation 118 is not detected at the nominal zones 128 when expected, the obstruction detection system 100 determines that an unexpected obstruction is present and generates the obstruction indication output.

[0245] For instance, if an obstruction is detected in the work area of the folding machine while the movable component 152 is descending, the obstruction indication output triggers an immediate change in the operation of the folding machine. This change can include actions such as stopping the descent of the movable component 152, reversing its direction, or initiating an emergency stop procedure for the entire folding machine.

[0246] The ability of the obstruction detection system 100 to distinguish between expected movements of the apparatus 150 and unexpected obstructions enhances both the safety and efficiency of the manufacturing process. It allows the apparatus 150 to operate at optimal speeds when no unexpected obstructions are present, while still providing robust protection against potential hazards.

[0247] In addition to dynamic exclusion zones, the obstruction detection system 100 may be configmed such that fixed exclusion zones 154 are not monitored. Referring to Figure 38, the emitter 140 is shown to include emission units 112 that enable monitoring of a forward portion of the moveable component 152. While the emitter 140 has emission units 112 that are capable of monitoring a rearward portion of the moveable component 152 (see Figure 40), these are deactivated in the configuration of Figure 38 and the rearward portion of the moveable component 152 is not monitored. The rearward portion may therefore be considered a fixed exclusion zone. Thus, in some embodiments, the obstruction detection system 100 deactivates one or more of the emission units 112 and sensor modules 114 during use, thereby defining a fixed exclusion zone. In this case, a physical barrier can be used to inhibit unintended movement into the rearward portion.

[0248] The particular extent of a fixed exclusion zone can be controlled by specific control of the particular emission units 112 and sensor modules 114 that are deactivated. Referring to Figure 39, a second group of emission units 112 and sensor modules 114 are activated, such that a region of space that formed part of the fixed exclusion zone of Figure 38 is now monitored. In Figure 40, a third group of emission units 112 and sensor modules 114 are activated, such that a region of space that formed part of the fixed exclusion zone of Figure 39 is now monitored. Figure 45 shows a schematic representation of a detector 130 for which a plurality of fixed exclusion zones 154 are defined. These fixed exclusion zones 154 comprise a plurality of sensor units 114 that can be selectively ignored or muted, depending on particular operating requirements of the machinery on which the detector 130 is being used.

[0249] It will be appreciated that the obstruction detection system 100 may employ use of both fixed and dynamic exclusion zones in use, as appropriate.

[0250] The at least one processor 102 may enforce the exclusion zones by deactivating the relevant emission units 112 and sensor modules 114 that correspond to the exclusion zones. That is, the at least one processor 102 may mute the relevant emission units 112 and sensor modules 114 that correspond to the exclusion zones. When an exclusion zone is designated, the at least one processor 102 may cease activating the emission units 112 within that exclusion zone, such that those emission units 112 do not emit electromagnetic radiation 118. Similarly, the at least one processor 102 may cease reading out data from the sensor modules 114 within the exclusion zone, such that those sensor modules 114 do not contribute to the obstruction detection process. This hardware-based enforcement of exclusion zones reduces computational load on the at least one processor 102 and may reduce power consumption by the obstruction detection system 100.

[0251] Alternatively, the at least one processor 102 may enforce the exclusion zones through softwarebased methods without deactivating the emission units 112 or sensor modules 114. In this approach, the emission units 112 within the exclusion zones continue to emit electromagnetic radiation 118, and the corresponding sensor modules 114 continue to detect electromagnetic radiation 118 and generate sensor data. However, the at least one processor 102 disregards or filters out the sensor data from sensor modules 114 within the exclusion zones when determining whether to generate an obstruction indication output. Even where the sensor data from a sensor module 114 within an exclusion zone indicates the presence of an obstruction, the at least one processor 102 does not generate an obstruction indication output based on that sensor data. This software-based enforcement allows the obstruction detection system 100 to maintain a complete record of all sensor data whilst selectively ignoring data from exclusion zones for obstruction detection purposes.Planar Testing System

[0252] Figure 22 shows a schematic diagram of a part of the obstruction detection system 100 that includes a planar testing system, according to some embodiments of the present disclosure. The planar testing system is used to controllably project electromagnetic radiation onto the face of the sensor 110 in a manner that enables confirmation that the sensor 110 is operating correctly and does not have appreciable x-y error. X-y error refers to inaccuracies in the spatial detection capabilities of the sensor 110. Specifically, x-y error occurs when the sensor 110 reports that electromagnetic radiation 118 is incident at a particular x-y coordinate position on the sensor 110 surface, but the electromagnetic radiation 118 is actually incident at a different x-y coordinate position. This type of error can arise from various sources, including sensor calibration drift, optical distortion in the optical system 113, thermal effects, mechanical stress on the sensor 110, or degradation of sensor components over time. X-y error can lead to incorrect identification of the zones 129 where electromagnetic radiation 118 is detected, which may result in false obstruction indications or failure to detect actual obstructions.

[0253] The planar testing system measures for x-y error by using planar testing emission units 112 A to emit electromagnetic radiation 112B at known, predetermined positions on the sensor 110. Each planartesting emission unit 112A is configured to direct electromagnetic radiation 112B to a specific target location on the sensor 110, typically via reflection off the window 119. Because the physical positions of the planar testing emission units 112A and the window 119 are fixed, the expected x-y coordinates where the reflected electromagnetic radiation 112B should be detected on the sensor 110 are known. The at least one processor 102 compares the actual detected position of the electromagnetic radiation 112B on the sensor 110 with the expected position. If the detected position differs from the expected position by more than an acceptable tolerance, this indicates the presence of x-y error in the sensor 110. By performing this test periodically during operation, the obstruction detection system 100 can identify when x-y error develops and take corrective action, such as recalibrating the sensor 110, adjusting the nominal pattern, or alerting an operator to perform maintenance.

[0254] The detector 130 includes a plurality of planar testing emission units 112A. In the illustrated embodiment, the detector 130 includes two planar testing emission units 112A positioned on either side of the illustrated sensor module 114. In some embodiments, there are four planar testing emission units 112A for each sensor module 114. Each planar testing emission unit 112A is configured to emit electromagnetic radiation 112B. A portion of this electromagnetic radiation 112B is reflected by a window 119, positioned in front of the optical system 113 of the obstruction detection system 100, and detected at a particular location on the sensor 110. This window 119 may be the cover 136 referred to herein.

[0255] In the illustrated embodiment, the detector 130 includes an upper planar testing emission unit 112A and a lower planar testing emission unit 112A. These may alternatively be referred to as a first planar testing emission unit 112A and a second planar testing emission unit 112A respectively. The electromagnetic radiation emitted by the upper planar testing emission unit 112A is reflected by the window 119 and detected at a lower portion of the sensor 110 (represented by a circle labelled with 112B in Figure 22), while the electromagnetic radiation emitted by the lower planar testing emission unit 112A is reflected by the window 119 and detected at an upper portion of the sensor 110 (again represented by a circle labelled with 112B in Figure 22). In some cases, the system 100 may include lateral planar testing emission units 112A whose electromagnetic radiation emissions are reflected by the window 119 and detected at opposing lateral portions of the sensor 110.

[0256] During normal operation, electromagnetic radiation emitted by an emission unit 112 is incident on the sensor 110. This is represented by a central circle on the face of the sensor 110 on the left section of Figure 22 (which shows a planar view of the face of the sensor 110).

[0257] The upper and lower circles on the face of the sensor 110, as shown in the left section of Figure 22, represent the electromagnetic radiation 112B emitted by the planar testing emission units 112A and reflected by the window 119. These circles indicate the locations where the reflected electromagnetic radiation 112B is incident on the sensor 110.

[0258] The planar testing emission units 112A may be used to ensure there is no x-y error in the sensor 110 by providing reference points at known locations on the sensor's 110 surface. By comparing the detected positions of the reflected electromagnetic radiation 112B from the planar testing emission units112A with their expected positions on the sensor 110, the system 100 can verily the accuracy of the sensor's 110 spatial detection capabilities. If the detected positions deviate from the expected positions, it may indicate an x-y error in the sensor 110.

[0259] The planar testing system may also be used periodically during operation to verily the continued accuracy of the sensor 110. This ongoing verification process may help ensure the reliability of the obstruction detection system 100 overtime and under various operating conditions.

[0260] Referring to Figure 41, in some embodiments, during the operating phase, one or more of the planar emission units 112A are used to confirm correct operation of the associated sensor unit 114 after the sensor unit 114 is used to observe for an obstruction. Figure 41 shows a timeline in which a planar emission unit 112A is activated subsequent to an activation of an emission unit 112. In such a case, step 206 of the method may comprise:1. Activating an emission unit 112 and subsequently seeking to detect the electromagnetic radiation emitted by the emission unit 112 using the corresponding sensor module 114.2. Following this, activating one or more planar testing emission unit 112A of the relevant sensor module 114 to test for x-y error associated with the sensor 110 of that sensor module 114.3. Another emission unit 112 activation step can then be performed.4. Following this, both the emission unit 112 and the planar testing unit 112A are deactivated so that the sensor 110 records a “dark frame” in which only ambient electromagnetic radiation is detected.

[0261] This sequence of steps can be repeated during the operating phase.Pentamirror System

[0262] Figure 17 illustrates a schematic view of an example emission unit 112, sensor module 114 pair of an obstruction detection system 100 that incorporates a pentamirror system 123. The pentamirror system 123 includes a number of mirrors positioned at angles to redirect the electromagnetic radiation 118 emitted by the emission unit 112.

[0263] The emission unit 112 is shown on the right side of the figure. The emission unit 112 is part of an emitter 140, and is designed to emit electromagnetic radiation 118 towards the sensor module 114, as described herein, but this time, via the pentamirror system 123.

[0264] The sensor module 114 is positioned on the left side of the figure. The electromagnetic radiation 118 emitted by the emission unit 112 is represented by lines in the figure. These lines show the path of the electromagnetic radiation from the emission unit 112, through the pentamirror system 123, and finally to the sensor module 114. The pentamirror system 123 redirects the electromagnetic radiation 118 multiple times before it reaches the sensor module 114.

[0265] The use of the pentamirror system 123 enhances the flexibility of the obstruction detection system 100, allowing for detection in non-linear paths and around obstacles. Alignment of the obstruction detection system 100 with rectangular areas is easier with the inclusion of the pentamirror system 123. Detector 130 and Emitter 140 Configurations

[0266] Figure 45 shows a schematic representation of a detector 130. The detector 130 of Figure 45 includes a plurality of sensor modules 114. The sensor modules 114 are arranged in a two-dimensional array, with the sensors 110 of these sensor modules 114 shown in Figure 45. The sensor modules 114 are organised in rows and columns. Thus, the sensors 110 of the sensor modules 114 are also arranged in rows and columns. This arrangement enables the detector 130 to cover an area to be sensed. The two- dimensional array configuration provides coverage across both horizontal and vertical dimensions of the monitored area.

[0267] The emission units 112 of the corresponding emitter 140 may be arranged in a matching two- dimensional array configuration. The emission units 112 may be arranged in the same number of rows and columns as the sensor modules 114. Alternatively, the emission units 112 may be arranged in a similar but not identical configuration to the sensor modules 114. In some cases, fewer emission units 112 may be used than the number of sensor modules 114. A single emission unit 112 may emit electromagnetic radiation 118 that is detected by multiple sensor modules 114. This configuration may reduce the overall number of emission units 112 required whilst maintaining detection coverage across the monitored area.

[0268] Figure 47 shows a schematic representation of another embodiment of a detector 130. The detector 130 of Figure 47 includes a plurality of sensor modules 114. The sensor modules 114 are arranged in a linear array. The sensor modules 114 are colinear. That is, the sensor modules 114 are arranged in a single row. The sensors 110 of the sensor modules 114, which are shown in Figure 47, are therefore arranged in a row. This arrangement may be referred to as a linear detector. The linear detector configuration enables the detector 130 to monitor a linear detection zone. The linear array provides coverage along a single dimension of the monitored area.

[0269] The corresponding emitter 140 may be arranged in a matching linear array configuration. The emission units 112 of the emitter 140 may be arranged in a single row. The emission units 112 may be colinear with each other. The emission units 112 may be arranged in the same linear configuration as the sensor modules 114. Alternatively, the emission units 112 may be arranged in a similar but not identical linear configuration to the sensor modules 114. In some cases, fewer emission units 112 may be used than the number of sensor modules 114. A single emission unit 112 may emit electromagnetic radiation 118 that is detected by multiple sensor modules 114. This configuration may reduce the overall number of emission units 112 required whilst maintaining detection coverage along the linear detection zone. Optimisation for Multiple Sensor Modules 114

[0270] The obstruction detection system 100 may comprise a plurality of sensor modules 114 that are connected to the at least one processor 102, as described herein. In some embodiments, complete image frames from each sensor module 114 are transferred into memory 104 and subsequently processed by the at least one processor 102. This approach requires substantial memory capacity and processing power, particularly when multiple sensor modules 114 are operating simultaneously. The storage and processing of complete image frames from numerous sensor modules 114 can impose significant demands on the computational resources of the system 100. To address these challenges, the obstruction detectionsystem 100 may employ a row-by-row processing approach in which the at least one processor 102 analyses pixel data from each sensor 110 as the data is clocked out from the sensor 110, without storing complete image frames in memory 104. The at least one processor 102 processes the incoming pixel data stream in real-time, examining each row 158 of pixels as it is received and making obstruction detection decisions based on a limited history of pixel data. This approach significantly reduces memory requirements and enables the at least one processor 102 to process data from a large number of sensor modules 114 simultaneously, such as 10 to 100 sensor modules 114, using minimal logic elements and memory resources. When image frames need to be saved for later viewing or analysis, the obstruction detection system 100 may employ a single frame grabber to capture frames from multiple sensor modules 114.

[0271] Referring to Figure 48, a schematic representation of a sensor 110 and the row-by-row processing approach is shown. The sensor 110 comprises a plurality of pixels arranged in rows 158. Each row 158 extends horizontally across the sensor 110 and comprises a plurality of individual pixels. The nominal zone 128 is shown on the sensor 110 as a circular region. The nominal zone 128 represents the area on the sensor 110 where electromagnetic radiation 118 emitted by the corresponding emission unit 112 is expected to be detected during normal, unobstructed operation.

[0272] Below the sensor 110, a sequence of groups of pixels 160 is shown. Each group of pixels 160 corresponds to pixel data from a respective row 158 of the sensor 110 as that row 158 is clocked out to the at least one processor 102. The groups of pixels 160 are arranged in a temporal sequence from left to right, representing the sequential processing of rows 158 over time. Some of the groups of pixels 160 include one or more high intensity pixel 162. The high intensity pixel(s) 162 represents the pixel within that group of pixels 160 that detects electromagnetic radiation 118 with the highest intensity value. These may alternatively be those above a predetermined threshold. The position of the high intensity pixel 162 within each group of pixels 160 indicates where electromagnetic radiation 118 is detected within the corresponding row 158 of the sensor 110.

[0273] The at least one processor 102 initiates the row-by-row processing by activating the emission unit 112 to emit electromagnetic radiation 118 towards the sensor 110. The at least one processor 102 controls the sensor 110 to begin clocking out pixel data one row 158 at a time. The pixel data from each row 158 is transmitted to the at least one processor 102 in a sequential manner. The at least one processor 102 receives the pixel data as a continuous data stream without storing complete image frames in memory 104. The at least one processor processes the pixel data from the sensor 110 in a row-by-row manner by reading out pixel data from the sensor 110 one row at a time.

[0274] As the at least one processor 102 receives the pixel data from each row 158, the at least one processor 102 analyses the intensity values of the pixels within that row 158. The at least one processor 102 compares the intensity value of each pixel to an intensity threshold. The at least one processor 102 identifies pixels within the row 158 that have intensity values exceeding the intensity threshold. The at least one processor 102 groups adjacent pixels that exceed the intensity threshold into groups of pixels 160. Each group of pixels 160 represents a contiguous region within the row 158 whereelectromagnetic radiation 118 is detected. Thus, the at least one processor 102 identifies one or more group of pixels within one or more row of pixels of the sensor 110 that comprise a pixel where electromagnetic radiation above a threshold intensity is detected.

[0275] For each identified group of pixels 160, the at least one processor 102 determines which pixel within that group has the highest intensity value. The at least one processor 102 designates this pixel as the high intensity pixel 162. In particular, the at least one processor identifies a high intensity pixel within the one or more group of pixels that includes a pixel that detects electromagnetic radiation. The at least one processor 102 records the x-coordinate (a first sensor coordinate) of the high intensity pixel 162 within the row 158. The at least one processor 102 also records the y-coordinate (a second sensor coordinate) corresponding to the row 158 from which the pixel data was obtained. Together, these coordinates define the x-y position of the high intensity pixel 162 on the sensor 110.

[0276] The at least one processor 102 compares the x-y position of the high intensity pixel 162 to the nominal zone 128 that was established during the commissioning phase. The at least one processor 102 determines whether the x-y position of the high intensity pixel 162 falls within the boundaries of the nominal zone 128. If the at least one processor 102 determines that the high intensity pixel 162 is located within the nominal zone 128, the at least one processor 102 determines that the detected electromagnetic radiation 118 matches the nominal pattern for that row 158. If the at least one processor 102 determines that the high intensity pixel 162 is located outside the nominal zone 128, the at least one processor 102 determines that the detected electromagnetic radiation 118 differs from the nominal pattern.

[0277] The at least one processor 102 repeats this process for each subsequent row 158 as the pixel data is clocked out from the sensor 110. The at least one processor 102 maintains a limited history of pixel data from recently processed rows 158. This limited history may comprise pixel data from the previous two, three, or five rows 158. The at least one processor 102 uses this limited history to track the position of detected electromagnetic radiation 118 across multiple rows 158. The at least one processor 102 can avoid storing pixel data from rows 158 beyond this limited history, thereby minimising memory usage.

[0278] As the at least one processor 102 processes each row 158, the at least one processor 102 accumulates information about whether the detected electromagnetic radiation 118 matches the nominal pattern. If the at least one processor 102 determines that electromagnetic radiation 118 is consistently detected outside the nominal zone 128 across multiple rows 158, or if electromagnetic radiation 118 is not detected within the nominal zone 128 when expected (i.e. the expected criteria is not met), the at least one processor 102 generates an obstruction indication output. The at least one processor 102 makes this determination in real-time as the pixel data is being received, without waiting for a complete image frame to be captured and stored.

[0279] This row-by-row processing approach enables the at least one processor 102 to efficiently process data from a large number of sensors 110 simultaneously. Because the at least one processor 102 does not store complete image frames in memory 104, the memory requirements for each sensor 110 are minimal. The at least one processor 102 only maintains a limited history of pixel data for each sensor 110, comprising data from a small number of recently processed rows 158. This allows the at least oneprocessor 102 to allocate memory resources efficiently across multiple sensors 110. The at least one processor 102 may process data from 10 to 100 sensors 110 using the same processing architecture. The at least one processor 102 may cycle through the sensors 110, processing one or more rows 158 from each sensor 110 in sequence. Alternatively, the at least one processor 102 may process data from multiple sensors 110 in parallel, with dedicated processing logic allocated to each sensor 110. The real-time processing approach reduces the computational complexity for each sensor 110, enabling the at least one processor 102 to handle data from numerous sensors 110 without requiring substantial increases in processing power or logic elements. This scalability makes the obstruction detection system 100 suitable for large-scale industrial applications where extensive monitoring coverage is required across multiple detection zones.Multiple Detection Zones on a Sensor 110

[0280] In some embodiments, the obstruction detection system 100 may be configured to direct electromagnetic radiation 118 from multiple spatially separated detection zones onto a single sensor 110. The system 100 as described above, was described to include a separate sensor 110 / sensing module 112 for each detection zone, which increases the number of sensors 110, the number of connections to the at least one processor 102, and the complexity of the system 100. Using multiple sensors 110 also increases the number of high-speed input / output lines required between the sensors 110 and the at least one processor 102. This can limit the achievable frame rates and increase the processing requirements. To address these challenges, the obstruction detection system 100 may employ an optical system that combines electromagnetic radiation 118 from multiple detection zones onto different, non-overlapping regions of a sensor 110. This approach reduces the total number of sensors 110 required (in some cases, to 1) whilst maintaining the same number of detection zones. By reducing the ratio of sensors 110 to processing elements, the system 100 can achieve higher frame rates, reduce the number of high-speed input / output connections, and decrease the overall size, cost, and complexity of the obstruction detection system 100.

[0281] Referring to Figures 49 and 50, the obstruction detection system 100 comprises an optical system configured to direct electromagnetic radiation 118 from multiple spatially separated sources onto a sensor 110 of a sensing module 114. The optical system includes a plurality of optical channels, each optical channel being configured to receive electromagnetic radiation 118 from a respective detection zone and direct that electromagnetic radiation 118 onto a distinct region of the sensor 110.

[0282] Each optical channel includes a polarising filter 164 and a bandpass filter 166. The polarising filter 164 is configured to allow electromagnetic radiation 118 with a specific polarisation to pass through whilst blocking electromagnetic radiation 118 with other polarisations. The bandpass filter 166 is configured to allow electromagnetic radiation 118 within a specific wavelength range to pass through whilst blocking electromagnetic radiation 118 outside that wavelength range. The polarising filter 164 and bandpass fdter 166 may be positioned in series along the optical path, such that electromagnetic radiation 118 passes through both filters before proceeding further through the optical channel.

[0283] Each optical channel includes one or more redirecting mirrors 168. The redirecting mirrors 168 are positioned at angles to redirect the electromagnetic radiation 118 along the optical path. In some embodiments, the redirecting mirrors 168 are positioned at approximately 45 degrees to the incoming electromagnetic radiation 118. The redirecting mirrors 168 direct the electromagnetic radiation 118 from each optical channel inward towards a central combining element.

[0284] The optical system includes a combining mirror 170. The combining mirror 170 is positioned to receive electromagnetic radiation 118 from the multiple optical channels. The combining mirror 170 may be a first surface knife-edge mirror. The combining mirror 170 combines the electromagnetic radiation 118 from the multiple optical channels into a single combined optical path. The electromagnetic radiation 118 from each optical channel remains spatially separated after passing the combining mirror 170, such that electromagnetic radiation 118 from different optical channels will be incident on different regions of the sensor 110.

[0285] The optical system includes a focusing lens 172. The focusing lens 172 is positioned in the combined optical path between the combining mirror 170 and the sensor 110. The focusing lens 172 focuses the electromagnetic radiation 118 from the multiple optical channels onto the sensor 110. The focusing lens 172 ensures that electromagnetic radiation 118 from each optical channel is focused onto a distinct, non-overlapping region of the sensor 110. The sensor 110 thereby receives electromagnetic radiation 118 from multiple detection zones simultaneously, with each detection zone corresponding to a different region of the sensor 110.

[0286] Referring to Figures 51 and 52, the spatial arrangement of the electromagnetic radiation 118 on the sensor 110 is shown. Figure 51 shows a perspective view of the sensor 110 with the electromagnetic radiation 118 from the multiple optical channels incident on the sensor 110 surface. The electromagnetic radiation 118 from each optical channel is incident on a distinct, non-overlapping region of the sensor 110. In the illustrated embodiment, electromagnetic radiation 118 from four optical channels is shown incident on four separate regions of the sensor 110. These regions are spatially separated on the sensor 110 surface. The electromagnetic radiation 118 from each optical channel does not overlap with the electromagnetic radiation 118 from the other optical channels on the sensor 110. This spatial separation enables the at least one processor 102 to distinguish between electromagnetic radiation 118 received from different detection zones by analysing which region of the sensor 110 detects the electromagnetic radiation 118.

[0287] Figure 51 shows a top view of the sensor 110, showing the electromagnetic radiation 118 from the multiple optical channels converging towards the sensor 110. The electromagnetic radiation 118 from each optical channel travels along a distinct optical path. The optical paths converge spatially but remain separated such that the electromagnetic radiation 118 from each optical channel is incident on a different region of the sensor 110.

[0288] The method 200 described herein remains applicable to embodiments where electromagnetic radiation 118 from multiple detection zones is directed onto a single sensor 110. In such embodiments, the commissioning phase may involve determining one or more nominal zones 128 for each distinctregion of the sensor 110 that corresponds to a respective detection zone. The at least one processor 102 may identify a first nominal zone 128 in a first region of the sensor 110 corresponding to electromagnetic radiation 118 from a first detection zone. The at least one processor 102 may identify a second nominal zone 128 in a second region of the sensor 110 corresponding to electromagnetic radiation 118 from a second detection zone. The at least one processor 102 may similarly identify additional nominal zones 128 for each additional detection zone. During the operating phase, the at least one processor 102 compares subsequently detected electromagnetic radiation 118 in each region of the sensor 110 to the respective nominal zone 128 for that region. The at least one processor 102 may generate an obstruction indication output in response to the subsequently detected electromagnetic radiation 118 in any region of the sensor 110 differing from the nominal pattern for that region. This approach enables the obstruction detection system 100 to monitor multiple detection zones simultaneously using a single sensor 110 whilst maintaining independent obstruction detection capabilities for each detection zone.

[0289] Referring to Figure 53, an alternative embodiment is shown in which electromagnetic radiation 118 from eight separate optical channels is directed onto a single sensor 110. The optical system includes eight optical channels, each configured to receive electromagnetic radiation 118 from a respective detection zone. The electromagnetic radiation 118 from each of the eight optical channels is directed through the optical system and focused onto the sensor 110 using the principles described with reference to Figures 49 to 52. The electromagnetic radiation 118 from each optical channel is incident on a distinct, non-overlapping region of the sensor 110. The eight regions are spatially separated on the sensor 110 surface such that the at least one processor 102 can distinguish between electromagnetic radiation 118 received from each of the eight detection zones. This configuration demonstrates the scalability of the optical system, enabling a single sensor 110 to monitor a larger number of detection zones simultaneously. The at least one processor 102 may determine a respective nominal zone 128 for each of the eight regions of the sensor 110 during the commissioning phase, and subsequently compare detected electromagnetic radiation 118 in each region to the corresponding nominal zone 128 during the operating phase. While eight channels are shown in the illustrated embodiment, other numbers of channels are also able to be used. Further, rather than being a 4x2 array, the optical channels could be focused on the sensor 110 in a differently dimensions array, a linear array, or an irregular distribution. Similar alternative configurations are possible where there is a different number of channels.

[0290] Referring to Figure 54, an alternative arrangement of the optical system is shown. In this embodiment, the optical system includes four optical channels configured to direct electromagnetic radiation 118 from four detection zones onto a single sensor 110. A first optical channel includes a first redirecting mirror 168A and a second redirecting mirror 168B. Electromagnetic radiation 118 in the first optical channel is redirected by the first redirecting mirror 168 A and then by the second redirecting mirror 168B before reaching a focusing lens 172. A second optical channel includes a third redirecting mirror 168C and a fourth redirecting mirror 168D. Electromagnetic radiation 118 in the second optical channel is redirected by the third redirecting mirror 168C and then by the fourth redirecting mirror 168D before reaching the focusing lens 172. A third optical channel includes a fifth redirecting mirror 168E and a sixthredirecting mirror 168F. Electromagnetic radiation 118 in the third optical channel is redirected by the fifth redirecting mirror 168E and then by the sixth redirecting mirror 168F before reaching the focusing lens 172. A fourth optical channel provides a direct optical path to the focusing lens 172 without any redirecting mirrors 168. Electromagnetic radiation 118 in the fourth optical channel travels directly to the focusing lens 172. The focusing lens 172 focuses the electromagnetic radiation 118 from all four optical channels onto the sensor 110, with electromagnetic radiation 118 from each optical channel being incident on a distinct, non-overlapping region of the sensor 110.

[0291] Referring to Figure 55, another alternative arrangement of the optical system is shown. In this embodiment, the optical system includes four optical channels configured to direct electromagnetic radiation 118 from four detection zones onto a single sensor 110. Each optical channel includes a respective focusing lens 172. A first optical channel includes a first focusing lens 172A, a first redirecting mirror 168A positioned downstream of the first focusing lens 172A, and a second redirecting mirror 168B positioned downstream of the first redirecting mirror 168A. Electromagnetic radiation 118 in the first optical channel passes through the first focusing lens 172A and is then redirected by the first redirecting mirror 168A and the second redirecting mirror 168B before reaching the sensor 110. A second optical channel includes a second focusing lens 172B, a third redirecting mirror 168C positioned downstream of the second focusing lens 172B, and a fourth redirecting mirror 168D positioned downstream of the third redirecting mirror 168C. Electromagnetic radiation 118 in the second optical channel passes through the second focusing lens 172B and is then redirected by the third redirecting mirror 168C and the fourth redirecting mirror 168D before reaching the sensor 110. A third optical channel includes a third focusing lens 172C, a fifth redirecting mirror 168E positioned downstream of the third focusing lens 172C, and a sixth redirecting mirror 168F positioned downstream of the fifth redirecting mirror 168E. Electromagnetic radiation 118 in the third optical channel passes through the third focusing lens 172C and is then redirected by the fifth redirecting mirror 168E and the sixth redirecting mirror 168F before reaching the sensor 110. A fourth optical channel includes a fourth focusing lens 172D and provides a direct optical path to the sensor 110 without any redirecting mirrors 168. Electromagnetic radiation 118 in the fourth optical channel passes through the fourth focusing lens 172D and travels directly to the sensor 110. The electromagnetic radiation 118 from all four optical channels is incident on the sensor 110, with electromagnetic radiation 118 from each optical channel being incident on a distinct, non-overlapping region of the sensor 110.

[0292] Referring to Figure 56, a further alternative arrangement of the optical system is shown. In this embodiment, the optical system includes four optical channels configured to direct electromagnetic radiation 118 from four detection zones onto a single sensor 110. Each optical channel includes a respective redirecting mirror 168. A first optical channel includes a first redirecting mirror 168A. A second optical channel includes a second redirecting mirror 168B. A third optical channel includes a third redirecting mirror 168C. A fourth optical channel includes a fourth redirecting mirror 168D. Electromagnetic radiation 118 in each optical channel is redirected by the respective redirecting mirror 168 towards a common focusing lens 172. The common focusing lens 172 is positioned downstream ofall the redirecting mirrors 168. Electromagnetic radiation 118 from all four optical channels passes through the common focusing lens 172. The common focusing lens 172 focuses the electromagnetic radiation 118 from all four optical channels onto the sensor 110. The electromagnetic radiation 118 from each optical channel is incident on a distinct, non-overlapping region of the sensor 110.

[0293] The optical system may be configured with any suitable number of optical channels depending on the requirements of the particular application. In some embodiments, the optical system may include two optical channels, enabling electromagnetic radiation 118 from two detection zones to be directed onto a common sensor 110. In other embodiments, the optical system may include three optical channels. In further embodiments, the optical system may include six optical channels. The number of optical channels may be selected based on factors such as the desired detection coverage, the available sensor 110 area, and the spatial resolution requirements for each detection zone. For each optical channel, the optical system includes appropriate optical components such as polarising filters 164, bandpass filters 166, redirecting mirrors 168, and focusing lenses 172 as needed to direct electromagnetic radiation 118 from that optical channel onto a distinct region of the sensor 110. The optical components for each optical channel may be arranged according to any of the configurations described with reference to Figures 49 to 57, or alternative configurations that achieve the objective of directing electromagnetic radiation 118 from multiple detection zones onto non-overlapping regions of a single sensor 110.

[0294] The detector 130 may incorporate the optical system described with reference to Figures 49 to 57 to reduce the number of sensors 110 required and the complexity of data processing. By including the polarising filters 164, bandpass filters 166, redirecting mirrors 168, combining mirror 170, and focusing lens 172 at the detector 130, multiple sensor modules 114 can share a single sensor 110, or only one sensor module 114 may be necessary. This configuration reduces the total number of physical sensors 110 within the detector 130 whilst maintaining the same effective sensing capability. The reduction in the number of sensors 110 decreases the number of high-speed input / output connections required between the detector 130 and the at least one processor 102. This enables the at least one processor 102 to process data from multiple sensors 110 and / or detectors 130 more efficiently. The integrated optical system within the detector 130 thereby reduces the size, cost, and complexity of the obstruction detection system 100 whilst maintaining comprehensive detection coverage across multiple detection zones.

[0295] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. Accordingly, other implementations are within the scope of the following claims.

[0296] In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the disclosure.

Claims

CLAIMS1. An obstruction detection system comprising: a detector comprising a sensor module, the sensor module being configured to detect electromagnetic radiation that is emitted by an emitter and incident to a sensor of the sensor module; wherein the obstruction detection system is configured to: record commissioning sensor data, using the sensor module, during a commissioning phase in which the sensor module detects electromagnetic radiation emitted by the emitter; determine a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; compare subsequently detected electromagnetic radiation, that is emitted by the emitter and detected by the sensor module during an operating phase, to the nominal pattern; and generate an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

2. The obstruction detection system of claim 1, wherein recording the commissioning sensor data comprises: sampling the sensor, during the commissioning phase, to determine the commissioning sensor data that indicates at least one characteristic of electromagnetic radiation incident to the sensor during a period of the commissioning phase; and storing, in a memory of the obstruction detection system, the commissioning sensor data.

3. The obstruction detection system of claim 2, wherein the at least one characteristic comprises at least one of: a spatial distribution of electromagnetic radiation detected by the sensor; an intensity of electromagnetic radiation detected by the sensor; a wavelength of electromagnetic radiation detected by the sensor; a polarisation of electromagnetic radiation detected by the sensor; a timing of detection of electromagnetic radiation by the sensor; and x-y coordinates of pixels of the sensor at which electromagnetic radiation is detected.

4. The obstruction detection system of any one of claims 1 to 3, wherein determining the nominal pattern comprises identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

5. The obstruction detection system of claim 4, wherein determining the nominal pattern comprises: identifying areas of peak intensity on the sensor where electromagnetic radiation emitted by the emitter is detected above a threshold intensity; andclassifying the identified areas of peak intensity as the one or more nominal zones.

6. The obstruction detection system of claim 4, wherein determining the nominal pattern comprises: establishing an intensity threshold; classifying pixels detecting electromagnetic radiation emitted by the emitter with intensity above the intensity threshold as part of the one or more nominal zones; and storing x-y coordinates of the classified pixels in a memory of the obstruction detection system.

7. The obstruction detection system of claim 4, wherein determining the nominal pattern comprises: determining a maximum detected intensity of electromagnetic radiation emitted by the emitter and detected by the sensor; identifying regions of the sensor where intensity exceeds a percentage of the maximum detected intensity; and classifying the identified regions as the one or more nominal zones.

8. The obstruction detection system of claim 4, wherein determining the nominal pattern comprises: applying edge detection algorithms to the commissioning sensor data to identify boundaries between regions of high and low electromagnetic radiation detection on the sensor; identifying one or more regions bounded by the identified boundaries; and classifying the identified one or more regions as the one or more nominal zones.

9. The obstruction detection system of claim 4, wherein determining the nominal pattern comprises: filtering detected electromagnetic radiation based on at least one of wavelength, polarisation, and temporal characteristics to isolate electromagnetic radiation emitted by the emitter from ambient electromagnetic radiation; identifying regions of the sensor where the isolated electromagnetic radiation is detected; and classifying the identified regions as the one or more nominal zones.

10. The obstruction detection system of any one of claims 1 to 9, wherein comparing subsequently detected electromagnetic radiation to the nominal pattern comprises: identifying one or more zones of a sensor of the sensor module at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

11. The obstruction detection system of claim 10, wherein identifying the one or more zones comprises: analysing intensity distribution across the sensor to identify pixels where electromagnetic radiation above a threshold intensity is detected; andidentifying contiguous regions of pixels detecting electromagnetic radiation as the one or more zones.

12. The obstruction detection system of claim 10, wherein identifying the one or more zones comprises: applying edge detection algorithms to identify boundaries of regions where electromagnetic radiation is detected on the sensor; and classifying regions bounded by the identified boundaries as the one or more zones.

13. The obstruction detection system of any one of claims 10 to 12, wherein comparing the zones to the one or more nominal zones comprises calculating a spatial overlap between the one or more zones and the one or more nominal zones.

14. The obstruction detection system of any one of claims 10 to 13, wherein comparing the zones to the one or more nominal zones comprises determining a positional offset between a centroid of the one or more zones and a centroid of the one or more nominal zones.

15. The obstruction detection system of any one of claims 10 to 14, wherein comparing the one or more zones to the one or more nominal zones of the nominal pattern comprises determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

16. The obstruction detection system of claim 15, wherein the difference comprises at least one of: a spatial difference in position on the sensor between the one or more zones and the one or more nominal zones; an intensity difference between electromagnetic radiation detected in the one or more zones and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase; a shape difference between the one or more zones and the one or more nominal zones; and a size difference between the one or more zones and the one or more nominal zones.

17. The obstruction detection system of claim 15 or claim 16, wherein determining the difference comprises: calculating a weighted average position of detected electromagnetic radiation within the one or more zones by weighting each pixel's coordinates by its detected intensity; comparing the weighted average position to a weighted average position of the one or more nominal zones; and determining a positional deviation based on the comparison.

18. The obstruction detection system of any one of claims 15 to 17, wherein the obstruction indication output is generated when the difference is greater than a difference threshold.

19. The obstruction detection system of claim 18, wherein the difference threshold is at least one of: a surface area overlap threshold, the surface area overlap threshold defining a minimum acceptable overlap between the one or more zones and the one or more nominal zones; a positional deviation threshold, the positional deviation threshold defining a maximum acceptable positional offset between the one or more zones and the one or more nominal zones; and an intensity deviation threshold, the intensity deviation threshold defining a maximum acceptable difference in intensity between electromagnetic radiation detected in the one or more zones during the operating phase and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase.

20. The obstruction detection system of any one of claims 1 to 19, wherein the obstruction indication output is configured to change an operating parameter of an apparatus associated with the obstruction detection system.

21. The obstruction detection system of claim 20, wherein: the apparatus is positioned within, or near, a detection zone between the emitter and the detector, thereby being associated with the obstruction detection system; the operating parameter comprises at least one of a speed of a movable component of the apparatus, a position of a movable component of the apparatus, and an operational state of the apparatus; and changing the operating parameter comprises at least one of reducing the speed of the moveable component, initiating a controlled stop sequence of the apparatus, altering a trajectory of the movable component, and initiating an emergency stop procedure for the apparatus.

22. The obstruction detection system of claim 20 or claim 21, wherein the apparatus comprises a piece of industrial equipment.

23. The obstruction detection system of any one of claims 1 to 22, further comprising at least one of: an optical filter that is configured to filter electromagnetic radiation that is incident to the sensor based on a wavelength of the electromagnetic radiation; and a polariser that is configured to enable electromagnetic radiation with a specific polarisation to pass through while blocking electromagnetic radiation with other polarisations.

24. The obstruction detection system of any one of claims 1 to 23, wherein the obstruction detection system is further configured to adjust the nominal pattern based on environmental conditions.

25. The obstruction detection system of claim 24, wherein adjusting the nominal pattern based on environmental conditions comprises: detecting a change in a value of at least one parameter indicating a state of an environment of the obstruction detection system; measuring a shift in position of the one or more nominal zones on the sensor resulting from the detected change in environmental conditions; determining that the measured shift exceeds an adjustment threshold; and updating the nominal pattern to reflect the shifted position of the one or more nominal zones.

26. The obstruction detection system of any one of claims 1 to 25, further comprising the emitter.

27. The obstruction detection system of claim 26, wherein the emitter comprises a plurality of emission units, each being configured to emit electromagnetic radiation at the detector.

28. The obstruction detection system of claim 27, wherein: the detector comprises a plurality of sensor modules; and each emission unit is configured to emit electromagnetic radiation at a respective sensor module.

29. The obstruction detection system of any one of claims 1 to 28, wherein the obstruction detection system is further configured to: designate one or more regions of the detector that correspond to an expected movement path of an apparatus during normal operation of the apparatus as dynamic exclusion zones of the detector; and selectively disregard sensor data generated by sensor modules of the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected apparatus movement.

30. The obstruction detection system of claim 4, or any one of claims 5 to 29 when dependent on claim 4, wherein comparing subsequently detected electromagnetic radiation to the nominal pattern comprises: processing pixel data from the sensor in a row-by-row manner by reading out pixel data from the sensor one row at a time; identifying one or more groups of pixels within one or more rows of pixels of the sensor that comprise a pixel where electromagnetic radiation above a threshold intensity is detected; identifying a high intensity pixel within each group that detects electromagnetic radiation with the highest intensity value within the respective group; determining a first sensor coordinate and a second sensor coordinate of each high intensity pixel on the sensor; andcomparing the first sensor coordinate and the second sensor coordinate of the high intensity pixels to coordinates of pixels within the nominal zone to determine whether the subsequently detected electromagnetic radiation differs from the nominal pattern.

31. An obstruction detection system comprising: a detector comprising a plurality of sensor modules, each sensor module being configured to detect electromagnetic radiation that is: emitted by an emitter; and incident to a sensor of the sensor module; wherein the obstruction detection system is configured to: record commissioning sensor data for each sensor module, using the respective sensor module, during a commissioning phase in which the sensor modules detect electromagnetic radiation emitted by the emitter; determine, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; compare electromagnetic radiation that is subsequently detected, during an operating phase, by each of the sensor modules, to the nominal pattern of the respective sensor module; and generate an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing from the nominal pattern of that sensor module.

32. The obstruction detection system of any one of claims 1 to 31, wherein the obstruction detection system is configured to transmit the obstruction indication output to an apparatus to change an operating parameter of the apparatus.

33. A method comprising: recording commissioning sensor data, using a sensor module, during a commissioning phase of an obstruction detection system in which the sensor module detects electromagnetic radiation emitted by an emitter; determining a nominal pattern of electromagnetic radiation that is emitted by the emitter and detected by the sensor module during the commissioning phase, using the commissioning sensor data; comparing subsequently detected electromagnetic radiation, that is emitted by the emitter and detected by the sensor module during an operating phase, to the nominal pattern; and generating an obstruction indication output in response to the subsequently detected electromagnetic radiation differing from the nominal pattern.

34. The method of claim 33, further comprising changing an operating parameter of an apparatus associated with the obstruction detection system in response to the generation of the obstruction indication output.

35. The method of claim 34, wherein the apparatus is positioned within, or near, a detection zone between the emitter and a detector of the obstruction detection system, thereby being associated with the obstruction detection system.

36. The method of claim 35, wherein recording the commissioning sensor data comprises: sampling a sensor of the sensor module, during the commissioning phase, to determine the commissioning sensor data that indicates at least one characteristic of electromagnetic radiation incident to the sensor during a period of the commissioning phase; and storing, in a memory, the commissioning sensor data.

37. The method of claim 36, wherein the at least one characteristic comprises at least one of: a spatial distribution of electromagnetic radiation detected by the sensor; an intensity of electromagnetic radiation detected by the sensor; a wavelength of electromagnetic radiation detected by the sensor; a polarisation of electromagnetic radiation detected by the sensor; a timing of detection of electromagnetic radiation by the sensor; and x-y coordinates of pixels of a sensor of the sensor module at which electromagnetic radiation is detected.

38. The method of any one of claims 33 to 37, wherein determining the nominal partem comprises identifying one or more nominal zones on the sensor at which the electromagnetic radiation emitted by the emitter during the commissioning phase is detected.

39. The method of claim 38, wherein determining the nominal partem comprises: identifying areas of peak intensity on the sensor where electromagnetic radiation emitted by the emitter is detected above a threshold intensity; and classifying the identified areas of peak intensity as the one or more nominal zones.

40. The method of claim 38, wherein determining the nominal pattern comprises: establishing an intensity threshold; classifying pixels detecting electromagnetic radiation emitted by the emitter with intensity above the intensity threshold as part of the one or more nominal zones; and storing x-y coordinates of the classified pixels in a memory of the obstruction detection system.

41. The method of claim 38, wherein determining the nominal pattern comprises: determining a maximum detected intensity of electromagnetic radiation emitted by the emitter and detected by the sensor; identifying regions of the sensor where intensity exceeds a percentage of the maximum detected intensity; and classifying the identified regions as the one or more nominal zones.

42. The method of claim 38, wherein determining the nominal pattern comprises: applying edge detection algorithms to the commissioning sensor data to identify boundaries between regions of high and low electromagnetic radiation detection on the sensor; identifying one or more regions bounded by the identified boundaries; and classifying the identified one or more regions as the one or more nominal zones.

43. The method of claim 38, wherein determining the nominal pattern comprises: filtering detected electromagnetic radiation based on at least one of wavelength, polarisation, and temporal characteristics to isolate electromagnetic radiation emitted by the emitter from ambient electromagnetic radiation; identifying regions of the sensor where the isolated electromagnetic radiation is detected; and classifying the identified regions as the one or more nominal zones.

44. The method of any one of claims 33 to 43, wherein comparing subsequently detected electromagnetic radiation to the nominal pattern comprises: identifying one or more zones of a sensor of the sensor module at which the subsequently detected electromagnetic radiation emitted by the emitter is detected; and comparing these zones to the one or more nominal zones of the nominal pattern.

45. The method of claim 44, wherein identifying the one or more zones comprises: analysing intensity distribution across a sensor of the sensor module to identify pixels where electromagnetic radiation above a threshold intensity is detected; and identifying contiguous regions of pixels detecting electromagnetic radiation as the one or more zones.

46. The method of claim 44 or claim 45, wherein identifying the one or more zones comprises: applying edge detection algorithms to identify boundaries of regions where electromagnetic radiation is detected on the sensor; and classifying regions bounded by the identified boundaries as the one or more zones.

47. The method of any one of claims 44 to 46, wherein comparing the zones to the one or more nominal zones comprises calculating a spatial overlap between the one or more zones and the one or more nominal zones.

48. The method of any one of claims 44 to 47, wherein comparing the zones to the one or more nominal zones comprises determining a positional offset between a centroid of the one or more zones and a centroid of the one or more nominal zones.

49. The method of any one of claims 44 to 48, wherein comparing the one or more zones to the one or more nominal zones of the nominal pattern comprises determining a difference between the one or more zones and the one or more nominal zones of the nominal pattern.

50. The method of claim 49, wherein the difference comprises at least one of: a spatial difference in position on the sensor between the one or more zones and the one or more nominal zones; an intensity difference between electromagnetic radiation detected in the one or more zones and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase; a shape difference between the one or more zones and the one or more nominal zones; and a size difference between the one or more zones and the one or more nominal zones.

51. The method of claim 49 or claim 50, wherein determining the difference comprises: calculating a weighted average position of detected electromagnetic radiation within the one or more zones by weighting each pixel's coordinates by its detected intensity; comparing the weighted average position to a weighted average position of the one or more nominal zones; and determining a positional deviation based on the comparison.

52. The method of any one of claims 49 to 51, wherein the obstruction indication output is generated when the difference is greater than a difference threshold.

53. The method of claim 52, wherein the difference threshold is at least one of: a surface area overlap threshold, the surface area overlap threshold defining a minimum acceptable overlap between the one or more zones and the one or more nominal zones; a positional deviation threshold, the positional deviation threshold defining a maximum acceptable positional offset between the one or more zones and the one or more nominal zones; and an intensity deviation threshold, the intensity deviation threshold defining a maximum acceptable difference in intensity between electromagnetic radiation detected in the one or more zones during theoperating phase and electromagnetic radiation detected in the one or more nominal zones during the commissioning phase.

54. The method of any one of claims 33 to 53, wherein the obstruction indication output is configured to change an operating parameter of an apparatus associated with the obstruction detection system.

55. The method of claim 54, wherein the apparatus is positioned within, or near, a detection zone between the emitter and the detector, thereby being associated with the obstruction detection system; the operating parameter comprises at least one of a speed of a movable component of the apparatus, a position of a movable component of the apparatus, and an operational state of the apparatus; and changing the operating parameter comprises at least one of reducing the speed of the moveable component, initiating a controlled stop sequence of the apparatus, altering a trajectory of the movable component, and initiating an emergency stop procedure for the apparatus.

56. The method of any one of claims 34, 35, 54 and 55, wherein the apparatus comprises a piece of industrial equipment.

57. The method of any one of claims 33 to 56, further comprising adjusting the nominal pattern based on environmental conditions.

58. The method of claim 57, wherein adjusting the nominal pattern based on environmental conditions comprises: detecting a change in a value of at least one parameter indicating a state of an environment; measuring a shift in position of the one or more nominal zones on the sensor resulting from the detected change in environmental conditions; determining that the measured shift exceeds an adjustment threshold; and updating the nominal pattern to reflect the shifted position of the one or more nominal zones.

59. The method of any one of claims 33 to 58, further comprising: designating one or more regions of a detector that correspond to an expected movement path of an apparatus during normal operation of the apparatus as dynamic exclusion zones of the detector; and selectively disregarding sensor data generated by sensor modules of the dynamic exclusion zones when comparing subsequently detected electromagnetic radiation to the nominal pattern, thereby avoiding false obstruction indications due to expected apparatus movement.

60. The method of claim 38, or any one of claims 39 to 59 when dependent on claim 38, wherein comparing subsequently detected electromagnetic radiation to the nominal pattern comprises:processing pixel data from a sensor of an obstruction detection system in a row-by-row manner by reading out pixel data from the sensor one row at a time; identifying one or more groups of pixels within one or more rows of pixels of the sensor that comprise a pixel where electromagnetic radiation above a threshold intensity is detected; identifying a high intensity pixel within each group that detects electromagnetic radiation with the highest intensity value within the respective group; determining a first sensor coordinate and a second sensor coordinate of each high intensity pixel on the sensor; and comparing the first sensor coordinate and the second sensor coordinate of the high intensity pixels to coordinates of pixels within the nominal zone to determine whether the subsequently detected electromagnetic radiation differs from the nominal pattern.

61. A method comprising: recording commissioning sensor data for each of a plurality of sensor modules, using the respective sensor module, during a commissioning phase of an obstruction detection system in which the sensor modules detect electromagnetic radiation emitted by the emitter; determining, for each sensor module, a nominal pattern of electromagnetic radiation emitted by the emitter and detected by the respective sensor module during the commissioning phase, using the commissioning sensor data; comparing electromagnetic radiation that is subsequently detected, during an operating phase of the obstruction detection system, by each of the sensor modules, to the nominal pattern of the respective sensor module; and generating an obstruction indication output in response to the electromagnetic radiation that is subsequently detected by at least one of the sensor modules differing the nominal pattern of that sensor module.

62. The method of claim 61, further comprising transmitting the obstruction indication output to an apparatus to change an operating parameter of the apparatus.

63. The method of claim 61 , further comprising changing a value of an operating parameter of an apparatus in response to the generation of the obstruction indication output.

Images