Optoelectronic safety device, its method of operation and safety system including that device

Abstract

To provide an optoelectronic safety device capable of improving the safety of an operator of an industrial plant.SOLUTION: An opto-electronic safety device (1) for an industrial plant (100) provided with a machine (101) positioned within a predetermined monitoring area (A) includes: imaging means (14) configured to capture digital images (D) of the monitoring area (A); and an electronic control unit (16), which is configured to: command the imaging means (14) to capture the digital images (D) for a predetermined monitoring period; process the digital images (D) to determine a dangerous condition when a movement of persons within the monitoring area (A) is determined during that monitoring period; prevent the machine (101) from starting if a dangerous condition is determined, or vice versa; and allow the machine (101) to start if the dangerous condition is not determined.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority to Italian Patent Application No. 102024000013681, filed June 14, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to an optoelectronic safety device for industrial plants, to a method for its operation and to a safety system comprising such a device. [Background technology]

[0003] As is well known, industrial plants that may present hazardous situations during operation generally have protective perimeters to prevent unauthorized access.

[0004] For example, such hazardous situations occur when moving parts of machinery are operating under pressure and / or at elevated temperatures.

[0005] The protective perimeter typically comprises a safety door and an electronically controlled safety locking device that locks the safety door in the event of a hazardous situation.

[0006] In particular, starting of the machine is only permitted under safe conditions, i.e. when the safety doors are closed and locked by the respective safety locking devices. In contrast, unlocking of the safety locking devices and opening of the safety doors is only permitted when the dangerous situation has ended.

[0007] Unfortunately, in some instances, even after the safety door has been closed and locked, the operator may be accidentally trapped within the safety perimeter, and the machine may therefore operate in a dangerous situation for the operator, which of course entails inconvenience.

[0008] To address this type of inconvenience, some manufacturers sell safety devices that continuously monitor the machine's surroundings while it is operating and can immediately shut down the machine if it detects a dangerous situation, such as someone being too close to the machine.

[0009] For example, such safety devices may be based on laser scanner or radar (RADAR: Radio Detection and Ranging) technology and are configured to detect objects or people located in the immediate vicinity of the machine while the machine is in operation.

[0010] Unfortunately, laser scanner-based safety devices are very expensive and have a very narrow field of view, limiting the range of areas that can be monitored.

[0011] On the other hand, radar devices are unable to precisely define the boundaries of the monitored area around the machine and often produce false positives, caused by, for example, a person or object moving outside the protective barrier, which of course results in unnecessary downtime and has a negative impact on the productivity of the machine.

[0012] Furthermore, the above known devices have proven susceptible to tampering: in fact, simply placing an immovable obstacle in front of the device will cause the device to constantly detect no movement, thus preventing safety intervention. Summary of the Invention [Problem to be solved by the invention]

[0013] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optoelectronic safety device that overcomes the above-mentioned drawbacks and makes it possible to improve the safety of operators of industrial plants. [Means for solving the problem]

[0014] In accordance with the above objectives, the present invention provides an optoelectronic safety device as defined in claim 1 and in any claims preferably but not necessarily dependent thereon.

[0015] Furthermore, the present invention also provides a method for operating an optoelectronic safety device and a safety system according to the related claims.

[0016] The claims describe preferred embodiments of the present invention and form an integral part of this specification.

[0017] For a better understanding of the invention, some implementations thereof will now be described, by way of non-limiting example and with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a perspective view, with parts removed for clarity, of an industrial plant comprising an optoelectronic safety device made in accordance with the present invention; [Figure 2] 2 is a perspective view, with portions removed for clarity, of the optoelectronic safety device shown in FIG. 1; [Figure 3] 2 is a schematic diagram of the architecture of the optoelectronic safety device shown in FIG. 1, with parts removed for clarity. [Figure 4] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 5] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 6] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 7] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 8] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 9] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 10] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 11] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 12] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 13] 2 is a schematic diagram of several steps in the operation of the optoelectronic safety device shown in FIG. 1; [Figure 14] 2 is a perspective view, with parts removed for clarity, of an alternative construction form of the plant shown in FIG. 1; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] With reference to the example shown in FIG. 1, the number 100 denotes an industrial machine or installation comprising a machine 101, such as for example a manipulator robot, a textile machine, a milling machine, a lathe and / or other similar machine.

[0020] Additionally, the system 100 preferably comprises a security perimeter that at least partially surrounds the machine 101 and is intended to prevent unauthorized access to the machine 101. For example, the security perimeter may comprise a mechanical guard wall.

[0021] More specifically, and with reference to FIG. 1, the safety perimeter preferably includes a protective wall 102 surrounding a machine 101 and including an opening 103 that allows safe access to the machine 101 .

[0022] Preferably, but not necessarily, the access door 103 is configured as an emergency door and comprises a fixed part 104 or frame integral with the protective barrier 102 and shaped to define an access opening 105 to the machine 101, and a movable part 106 or leaf / door movably supported by the fixed part 104 between an open position giving access to the machine 101 and a closed position blocking the access opening 105.

[0023] Furthermore, the system 100 preferably comprises an access control device configured to perform access control functions via the entrance / exit 103, i.e. configured to detect and / or prevent access via said entrance / exit 103 within the security perimeter.

[0024] The access control device may comprise a device for detecting passage through said doorway 103, for example a laser barrier.

[0025] Alternatively, if the passageway 103 is configured as a safety door, the access control device may comprise an electronically operated safety locking device 108 configured to be positioned on the safety door 103 and configured to lock the safety door 103 in a closed position on command.

[0026] Preferably, the device 108 is further configured to allow operation of the machine 101 only if it does not detect and / or prevent access via said gap 103 within the safety boundary, and in contrast is configured to inhibit operation of the machine 101 if it does detect and / or allow access via said gap 103 within the safety boundary.

[0027] Furthermore, the device 108 is configured to transmit a safety signal at least when it allows operation of the machine 101 .

[0028] For example, if the passageway 103 is configured as a safety door, the device 108 may be further configured to permit operation of the machine 101 only if the safety door is closed and locked, and conversely, to prevent operation of the machine 101 if the safety door is open and / or unlocked.

[0029] Referring to the non-limiting example illustrated in FIG. 1, the device 108 preferably comprises a safety switch 110 configured to be positioned on the fixed portion 104 of the safety door 103 .

[0030] Furthermore, the device 108 preferably comprises an actuator 112 configured to be positioned on the movable part 106 of the safety door 103, the actuator 112 being configured to lock the safety door 103 by cooperating with the switch 110 when the movable part 106 is placed in the closed position.

[0031] In particular, the switch 110 is configured to, upon command, hold the actuator 112 to lock the safety door 103 in a closed position. For example, the switch 110 may include a locking mechanism that, upon command, is configured to lock the actuator 112 in contact with the same switch 110, thereby preventing the safety door 103 from opening.

[0032] Alternatively, the locking mechanism of the switch 110 can have a locking configuration that locks the actuator 112 in contact with the switch 110 and an unlocking configuration that allows the actuator 112 to move away from the switch 110.

[0033] Furthermore, the device 108 may comprise sensor means 114 configured to determine when the safety door 103 is closed and / or locked.

[0034] The sensor means 114 may, for example, comprise a proximity sensor configured to determine whether the actuator 112 is in proximity to and / or in contact with the switch 110 .

[0035] Additionally or alternatively, the sensor means 114 may comprise a position sensor (not shown in the drawings) associated with the locking mechanism, if present, and configured to determine when the locking mechanism is in the locked configuration.

[0036] The device 108 may further comprise a switching means 116 electrically connected to the sensor means 114 , the switching means 116 being configured to generate a safety signal based on data / signals obtained by the sensor means 114 .

[0037] Please note that here and hereafter "electrically" also means "electronically."

[0038] Furthermore, the device 108 may comprise an electronic control unit (not shown) connected to the sensor means 114 and the switching means 116, the electronic control unit being configured to drive the switching means 116 based on data / signals generated by the sensor means 114.

[0039] More specifically, the switching means 116 may be in either an active state, which generates an electrical or electronic signal indicating that the actuator 112 is in contact with and / or locked against the switch 110, or a passive state, which either does not provide a signal or generates an electrical or electronic signal indicating that the actuator 112 is not in contact with and / or locked against the switch 110.

[0040] The electronic control unit may be configured to switch the switching means 116 from a passive state to an active state when the sensor means 114 detects that the safety door 103 is closed and / or locked.

[0041] In contrast, the electronic control unit may be configured to switch or keep the switching means 116 in a passive state when the sensor means 114 detects that the safety door 103 is open and / or unlocked.

[0042] Preferably, the switching means 116 may comprise a pair of safety electronic outputs of the OSSD (Output Signal Switching Device) type driven by an electronic control unit.

[0043] By way of example only, a safety output in an active state generates a signal and assumes a "1" or "on" logic state, and when in a passive state does not generate a signal and assumes a "0" or "off" logic state.

[0044] Alternatively or additionally, the switching means 116 can be driven by an electronic control unit to generate a digital signal, i.e., a bit sequence, encoding a telegram according to a communication protocol, which may be of known type, such as IO-Link, Profinet, EtherCAT, EtherNet / IP, IO-Link Safety, Profisafe, CIP Safety, Safety over EtherCAT (FSoE), or any other equivalent communication protocol. In this case, specific bits of the telegram encode information about the situation detected by the sensor means 114. Furthermore, the telegram preferably includes verification bits (CRC, watchdog, sequence number with respect to previously transmitted telegrams) configured to ensure the integrity of the telegram itself, which verification bits are generated in correspondence with other bits of the telegram and / or with previously transmitted telegrams.

[0045] By way of example, the switching means 116 may be electrically connected to an electronic control unit 118 that controls the system 100 to prevent operation of the machine 101 when the safety door 103 is open and / or unlocked.

[0046] More specifically, the control unit 118 is adapted to control the operation of the machine 101 based on the safety signal generated by the switching means 116 .

[0047] For example, the control unit 118 may be configured to prevent operation of the machine 101 when the switching means 116 is in a passive state, and conversely to allow operation of the machine 101 when the switching means 116 is in an active state.

[0048] With reference to the schematic example shown in Figure 1, the system 100 further comprises at least one optoelectronic safety device 1 configured to monitor a predetermined monitoring area A. A machine 101 is positioned within the monitoring area A.

[0049] In other words, the monitoring area A preferably comprises the part of the plant 100 in which the machine 101 is located and the space in the vicinity of the machine 101 , in particular surrounding the same machine 101 .

[0050] More specifically, monitoring area A preferably comprises the portion of system 100 located within protective wall 102 and comprising machine 101 .

[0051] Furthermore, the device 1 is preferably configured to be placed on a protective wall 102 .

[0052] In particular, the device 1 is preferably configured to be placed in a fixed / stationary position, ie configured for stationary use.

[0053] More specifically, preferably, device 1 is configured to be positioned above and to the side of machine 101 for monitoring the surroundings of the machine 101 itself.

[0054] Furthermore, the device 1 is separate and independent from the access control device 108 .

[0055] As will be explained in more detail below, in one possible implementation, the device 1 is configured to receive a monitoring activation signal when the machine 101 is not in operation, i.e. before start-up.

[0056] Furthermore, the device 1 is configured to monitor the monitoring area A for a predetermined time interval before starting the machine 101 .

[0057] For example, the monitoring time interval can be between 2 seconds and 20 seconds.

[0058] Furthermore, the device 1 is configured to prevent the machine 101 from starting up if it detects a dangerous situation for the operator in the monitoring area A.

[0059] In contrast, the device 1 is configured to allow the machine 101 to start only if a safe condition is determined during the monitoring period.

[0060] In this description and in the claims, a hazardous situation is defined as a situation in which an operator may come into contact with a hazardous element of machine 101 if machine 101 were to be started.

[0061] More specifically, a dangerous situation occurs when a moving object, tangible body, or person P (hereinafter simply referred to as a "person") is present within the monitoring area A.

[0062] In other words, a dangerous situation occurs when the device 1 detects the movement of a person P within the monitoring area A.

[0063] For example, a dangerous situation may occur if the safety door 103 is closed and locked by the device 108 while the person P is accidentally still inside the protective barrier 102. In this case, the person P is in fact trapped inside the protective barrier 102 and, if the machine 101 is started, the person P may come into contact with dangerous elements of the machine 101, such as, for example, moving, high pressure, high temperature or similar elements.

[0064] In contrast, a safe condition refers to a situation in which it is not possible for the person P to come into contact with the machine 101 after the machine 101 has been started.

[0065] More specifically, the safe condition occurs when there is no person P moving within the monitoring area A.

[0066] For example, the safety condition is realized when the safety door 103 is closed and locked by the device 108 while the person P is not trapped inside the protective wall 102 .

[0067] It should be noted that the term "moving / moving" includes both macro-movements that may be made by a person positioned within the monitoring area A, such as movement due to walking or large limb movements, and micro-movements that may be made by a person who is substantially stationary at a point within the monitoring area A, such as chest movement due to breathing, small limb movements necessary to maintain balance, myoclonus, or small movements of anatomical protrusions such as fingers, hands, or feet.

[0068] Preferably, the device 1 is configured to communicate with the machine 101 and / or the control unit 118 of the system 100. For example, the device 1 may be connected to the machine 101 and / or the control unit 118 via a cable or a wireless network. Furthermore, preferably, the device 1 is configured to communicate with an access control device, for example via a wired connection or a wireless network.

[0069] According to one possible embodiment of the invention, the device 1 is further configured to monitor the monitoring area A after initiation of an access control function by said access control device and before starting up the machine 101. For example, the device 1 is configured to monitor the monitoring area A after the safety door 103 has been closed and locked by the device 108 and before starting up the machine 101.

[0070] Referring to Figures 1 and 2, the device 1 is configured to acquire images of a monitoring area A during a monitoring period and determine the presence of a person P moving within the monitoring area A based on the acquired images.

[0071] Preferably, the access control device and device 1 are combined to form a safety system for system 100 that controls access to passageway 103 and allows starting of machine 101 only if there is no person P moving within monitoring area A before starting machine 101.

[0072] For example, the safety locking device 108 and device 1 combine to form a safety system for the system 100 that allows the machine 101 to start only if the safety door 103 is closed and locked and there is no person P moving within the monitoring area A before the machine 101 starts.

[0073] Referring to the example shown in FIGS. 1 and 2, the device 1 comprises an outer housing or enclosure 3, advantageously having a box-like structure and adapted to be positioned on a protective wall 102.

[0074] Preferably, the casing 3 has a shape that is advantageously substantially parallelepiped and is hollow inside.

[0075] More specifically, the casing 3 preferably comprises a base 5 and a lid 6 which have complementary shapes and are preferably cup-shaped.

[0076] Preferably, the base 5 and lid 6 are fixedly joined together at their peripheral edges.

[0077] Additionally, the casing 3 preferably includes a gasket 8 configured to be interposed between the base 5 and the lid 6 to substantially seal the casing 3 .

[0078] Furthermore, the housing 3 may comprise a transpiration element or membrane 9 which may prevent the accumulation of moisture within the housing 3 and allow heat exchange between the interior of the housing 3 and the external environment.

[0079] Referring to FIG. 2, the device 1 preferably includes an anchor bracket 10 for positioning the housing 3 on a protective wall 102 .

[0080] More specifically, the anchor bracket 10 preferably has an elongated shape. A first end 10a of the anchor bracket 10 is configured to be positioned on the protective wall 102. A second end 10b of the anchor bracket 10, located opposite the first end 10a, is configured to be connected to the housing 3.

[0081] Preferably, the device 1 further comprises a joint 12 interposed between the anchor bracket 10 and the housing 3, which allows the orientation of the housing 3 relative to the protective wall 102 to be changed.

[0082] More specifically, the joint 12 is a two-degree-of-freedom joint configured to allow the casing 3 to rotate relative to the anchor bracket 10 about two lateral rotation axes R1 and R2 that are preferably perpendicular to each other.

[0083] Furthermore, with reference to the example shown in FIGS. 2 and 3, the device 1 comprises imaging means or image capturing means 14 configured to obtain / capture an image of the monitoring area A.

[0084] Furthermore, the imaging means 14 is configured to capture images at a predetermined capture frequency or frame rate.

[0085] Preferably, the imaging means 14 is housed within the casing 3 .

[0086] More specifically, the casing 3 has a transparent or translucent part 15 positioned at the imaging means 14 .

[0087] Furthermore, the device 1 comprises an electronic control unit 16 in communication with the imaging means 14 and configured to drive the imaging means 14 to acquire images of the monitoring area A and to determine safe and / or dangerous situations based on the images acquired by the imaging means 14.

[0088] More specifically, preferably, the electronic control unit 16 is configured to receive a monitoring activation signal when the machine 101 is not in operation.

[0089] Furthermore, the electronic control unit 16 is configured to capture images of the monitoring area A over a monitoring period by controlling the imaging means 14 in response to the monitoring activation signal.

[0090] Furthermore, the electronic control unit 16 is configured to determine a dangerous or safe situation by processing the images captured by the imaging means 14 .

[0091] More specifically, the electronic control unit 16 is preferably configured to detect the movement of a person P located within the monitoring area A from the difference between at least two different digital images D acquired during the monitoring period.

[0092] It is clear that the term acquired digital image D refers both to digital images acquired directly by the imaging means 14 and to digital images acquired by pre-processing thereof.

[0093] Furthermore, the electronic control unit 16 is configured to prevent / inhibit starting of the machine 101 if a dangerous situation is determined, or conversely, to allow starting of the machine 101 if a safe situation is determined.

[0094] According to one possible embodiment of the invention, the electronic control unit 16 is configured to activate the imaging means 14 after initiation of said access control function, for example after closing and locking the safety door 103 via the device 108.

[0095] Preferably, the electronic control unit 16 is housed inside the housing 3 .

[0096] 3, the device 1 preferably comprises switching means 18 connected to the electronic control unit 16. Preferably, the switching means 18 is further configured to be connected to the control unit 118 of the system 100.

[0097] Furthermore, preferably, the switching means 18 is configured to alternate between mutually distinguishable active and passive / inactive states, and preferably, in the active state, the switching means 18 is configured to allow starting of the machine 101, and in the passive state, the switching means 18 is configured to prevent starting of the machine 101.

[0098] Preferably, the electronic control unit 16 is configured to drive the switching means 18 based on images / data acquired by the imaging means 14 .

[0099] More specifically, the electronic control unit 16 is preferably configured to normally drive the switching means 18 in the passive state.

[0100] Furthermore, the electronic control unit 16 is preferably configured to transition the switching means 18 from a passive state to an active state when a safe condition is determined.

[0101] In contrast, preferably, the electronic control unit 16 is configured to cause or maintain the switching means 18 in a passive state if a dangerous situation is determined.

[0102] Preferably, the switching means 18 is arranged to safely provide a safety signal S1 to the control unit 118 to allow or prevent starting of the machine 101.

[0103] As an example, if the safety signal S1 indicates that the electronic control unit 16 has determined a safe situation, the control unit 118 will allow the machine 101 to start. In contrast, if the safety signal S1 indicates that the electronic control unit 16 has determined a dangerous situation, the control unit 118 will not allow the machine 101 to start.

[0104] Preferably, the switching means 18 comprises an electrical communication interface arranged to be connected to the control unit 118 for providing the safety signal S1 to the control unit 118.

[0105] According to one possible implementation, the switching means 18 comprise a pair of safety electronic outputs of the OSSD (Output Signal Switching Device) type.

[0106] Alternatively or additionally, the switching means 18 may be driven by the electronic control unit 16 to generate a digital signal, i.e. a bit sequence, encoding a telegram according to a communication protocol, such as one of the communication protocols already mentioned and which will not be repeated for the sake of brevity, in which case specific bits of the telegram encode information regarding a safe or dangerous situation determined by the electronic control unit 16.

[0107] With reference to the example shown in FIG. 3, the imaging means 14 preferably comprises an optoelectronic imaging device 20, in particular a camera.

[0108] More specifically, the imaging means 14 advantageously comprises only a single optoelectronic imaging device 20 .

[0109] In particular, preferably, the optoelectronic image acquisition device 20 comprises only one camera, more advantageously only one two-dimensional camera.

[0110] Furthermore, the imaging means 14 does not comprise any optoelectronic imaging device other than the device 20 .

[0111] Furthermore, preferably, the device 1 does not have any additional sensors capable of determining the presence of a person moving in the vicinity of the machine 101. In particular, preferably, the device 1 does not have any detection devices based on radar technology and / or laser scanners or the like.

[0112] By way of example, the optoelectronic imaging device 20 may include an optical system or lens 22 capable of directing light toward an optoelectronic sensor 24 capable of converting the received light into a digital image or digital image signal. For example, the optoelectronic sensor 24 may be a CMOS (complementary metal oxide semiconductor) type sensor.

[0113] In use, the image capture means 14 is capable of supplying to the electronic control unit 16 a digital image D or a digital image signal encoding the captured image.

[0114] Preferably, the digital image D consists of a numerical array of points or pixels representing the image acquired by the imaging means 14 .

[0115] Furthermore, preferably, the digital image D is acquired from a single optoelectronic imaging device 20 and is therefore two-dimensional.

[0116] More specifically, the digital images D are preferably referenced to the same reference plane / frame of reference of the opto-electronic imaging device 20 .

[0117] Referring to the example shown in FIG. 3, the electronic control unit 16 preferably comprises an image processing unit 26, hereinafter also referred to as IPU 26 (Image Processing Unit), which is configured to receive the digital image D from the imaging means 14.

[0118] Preferably, the IPU 26 is connected to the imaging means 14 .

[0119] In use, the IPU 26 is preferably configured to control the imaging means 14 to capture images of the monitoring area A over a monitoring period.

[0120] According to one aspect of the invention, IPU 26 is preferably further configured to correct for distortions introduced by optical system 22 to digital image D, i.e., to perform a so-called "fisheye" correction. This correction is performed in a manner known per se and therefore, for the sake of brevity, will not be described further. Furthermore, IPU 26 is preferably configured to perform a transformation of digital image D in order to obtain from digital image D a new transformed digital image D referenced to a predetermined reference plane R.

[0121] More particularly, IPU 26 is preferably configured to be able to perform a projective or homographic transformation of digital image D, whereby a transformed digital image D relative to a predetermined reference plane R is obtained from digital image D. For example, reference plane R may include or coincide with a surface or floor on which machine 101 rests. IPU 26 preferably comprises a memory configured to store a transformation matrix or homographic matrix for transforming digital image D into a transformed digital image D relative to reference plane R.

[0122] According to one aspect of the present invention, the IPU 26 is preferably configured to determine / calculate the transformation matrix from a target image of a positioning or calibration target 200 configured to be positioned on a reference plane R.

[0123] More specifically, the imaging means 14 is preferably configured to acquire a target image of a positioning or calibration target 200 to be placed on the R reference plane.

[0124] The positioning target 200 may consist of, for example, a panel having predetermined graphic features on its surface. Alternatively or additionally, the positioning target 200 may comprise predetermined graphic features projected or drawn on the reference surface R.

[0125] Preferably, the IPU 26 is configured to be able to determine the position and / or orientation of the positioning target 200 relative to the device 1 based on the target image.

[0126] Furthermore, preferably, the IPU 26 is configured to calculate / determine a homographic transformation matrix for performing a transformation of the digital image D to a transformed digital image D relative to the reference plane R based on the image of the positioning target 200.

[0127] As will be described below, the IPU 26 is preferably configured to perform calculations of the transformation matrix on command during an initial calibration stage of the device 1 after positioning the device 1 on the protective wall 102 of the system 100.

[0128] Preferably, the IPU 26 is further configured to combine / multiply the digital image D with a transformation matrix to obtain a transformed digital image D relative to the reference plane R.

[0129] In use, this allows a digital image D acquired relative to the reference system of the device 1 to be transformed into a new transformed digital image D represented relative to the reference plane R and / or the machine 101.

[0130] The technical effect of this transformation relates to the ability to remove distortions in the digital image D due to the offset position of the device 1 relative to the reference plane R on which the mechanics 101 of the device 1 is located.

[0131] Since the imaging means 14 comprises a single optoelectronic imaging device 20, the acquired digital image D is in fact two-dimensional, and the dimensions of the person P represented in the digital image D and positioned on the reference plane R are affected by the distance between the person and the device 20. Thus, a person P of the same size is represented in the digital image D with different dimensions depending on the distance from the device 20.

[0132] As will become apparent, this prevents the setting of a tolerance threshold for identifying the movements of people located within the monitoring area A.

[0133] On the other hand, by converting digital image D into a transformed digital image D that is referenced to reference plane R, it is possible to normalize the dimensions of person P represented in transformed digital image D to reference plane R. Thus, people P of the same dimensions who are located on reference plane R at different distances from device 20 will be shown in transformed digital image D with the same dimensions relative to reference plane R.

[0134] For simplicity, the following description will omit the term "transformed" and refer more generally to digital image D. The term digital image D can be understood to mean either the digital image D acquired by image acquisition means 14 or the transformed digital image D processed by IPU 26.

[0135] Furthermore, preferably, IPU 26 is configured to perform filtering and saturation adjustment pre-processing of digital image D. This pre-processing is performed in a manner known per se and therefore will not be further described for the sake of brevity.

[0136] This filtering and saturation adjustment preprocessing can be performed on the acquired digital image D or on the transformed digital image D.

[0137] According to one aspect of the present invention, preferably, the IPU 26 is further configured to correct the digital image D to obtain a digital image having a constant resolution, particularly with respect to some portions of the person P represented in the digital image D located on the reference plane R.

[0138] More particularly, the IPU 26 is preferably configured to correct the digital image D using decimation and / or interpolation techniques known per se in the field of image processing to obtain a digital image having a constant resolution relative to the reference plane R.

[0139] According to a further aspect of the present invention, which is schematically illustrated in Figures 8, 9 and 10, the IPU 26 is preferably configured to be able to define masking regions or masking portions M in the digital image D which will be ignored / excluded in subsequent calculation operations for determining a dangerous situation.

[0140] In other words, preferably, the IPU 26 is configured to be able to divide the digital image D into regions or portions of interest X that will be subsequently processed for determining the danger situation, and masking regions M that will be ignored during the determination of the danger situation.

[0141] For example, masking region M may include or correspond to portions of digital image D relating to a wall portion of protective barrier 102, portions of facility 100 outside protective barrier 102, machine 101 and / or portions of machine 101, and / or a pulsating light source within facility 100, etc.

[0142] In other words, the masking area M may consist of a portion of the digital image D relating to an area of ​​the system 1 in which movement of a person or object not associated with a dangerous situation, such as a person moving outside the protective barrier 102, may be detected.

[0143] Preferably, IPU 26 is configured to process data / pixels that fall within a region of interest X of digital image D. In other words, IPU 26 is preferably configured to ignore data / pixels that fall within a masking region M of digital image D.

[0144] Additionally, IPU 26 is preferably configured to process digital image D to determine the numerical values ​​of one or more image characteristics / parameters / properties F of previously acquired digital image D.

[0145] For example, IPU26 may be configured to determine numerical values ​​related to image characteristics F, such as color-related numerical values ​​such as average color or grayscale values, maximum color or grayscale values, brightness, color centroids, and / or other similar parameters of digital image D and / or portions thereof.

[0146] More specifically, the IPU 26 is preferably configured to determine / calculate the numerical values ​​of one or more image features / parameters F by processing only the data / pixels contained in the region of interest X of the digital image D.

[0147] 3, the electronic control unit 16 preferably further comprises a pair of secure processing units 28, hereinafter also referred to as SPUs 28 (Secure Processing Units), both of which are configured to receive the previously processed numerical values ​​of the image characteristic F from the IPU 26.

[0148] Additionally, the SPU 28 is preferably configured to determine a dangerous or safe situation based on the image characteristics F received from the IPU 26 .

[0149] More specifically, the two SPUs 28 are configured to independently determine whether a situation is dangerous or safe based on the image characteristics F received from the IPU 26 .

[0150] By having the SPU 28 determine the hazardous situation based on the image characteristic F rather than directly on the digital image D, it is possible to significantly reduce the computational power required for the SPU 28. In fact, the SPU 28 is not used to process the digital image D, but only to compare the numerical values ​​of the image characteristic F processed by the IPU 26, as will be described in more detail below.

[0151] Preferably, the two SPUs 28 are further connected to the switching means 18 and configured to activate the switching means 18 depending on the determined unsafe or safe situation.

[0152] More specifically, each of these two SPUs 28 is preferably connected to a respective safety output of the device 1 and is configured to drive the switching means 18 depending on the state determined by the SPU 28 itself.

[0153] 4, the IPU 26 may be configured to provide the same numerical value of the image characteristic F to both SPUs 28. More specifically, the IPU 26 may be configured to provide the same numerical value of the image characteristic F processed from the same digital image D to the two SPUs 28.

[0154] In other words, in the implementation of FIG. 4, a packet of image characteristics F for each previously acquired digital image D is preferably sent from IPU 26 to two SPUs 28 .

[0155] For example, both SPUs 28 may receive numerical values ​​of color centroids or other image characteristics F obtained from the same digital image D from IPU 26 .

[0156] Furthermore, preferably, each of the two SPUs 28 is configured to compare / contrast the numerical values ​​of the image characteristic F for two different digital images D acquired at two different times and determine whether the difference between these numerical values ​​exceeds a predetermined safety threshold.

[0157] If the difference between the numerical values ​​of the image characteristic F of two different digital images D exceeds this safety threshold, this suggests that the two digital images D are different from each other and therefore movement of a person P has been detected within the monitoring area A.

[0158] On the other hand, if the difference between the numerical values ​​of the image characteristic F of two different digital images D is less than this safety threshold, this suggests that the two digital images D are substantially equivalent to each other and therefore no movement of person P has been detected within the monitoring area A.

[0159] For example, the safety threshold can be set to make it possible to identify / detect movements of person P that include an area having a minimum width exceeding a predetermined minimum value, for example between 1 square centimeter and 10 square centimeters.

[0160] According to one possible implementation, these two SPUs 28 may be configured to compare / contrast image characteristics F obtained from two digital images D acquired at two successive acquisition points in time, i.e., two successive frames.

[0161] It will be further understood that each of these two SPUs 28 may be configured to compare / contrast image characteristics F for two digital images D captured at two non-consecutive acquisition points in time.

[0162] In use, the IPU 26 may be configured to provide the SPU 28 with image characteristics F relating to advantageously successive digital images D during the monitoring period, while the two SPUs 28 are preferably configured to continuously compare image characteristics F relating to two digital images D at two mutually different points in time during the monitoring period.

[0163] If the difference between the numerical values ​​of the image characteristic F compared by at least one of the two SPUs 28 exceeds the safety threshold, this SPU 28 is configured to determine a dangerous situation and preferably activate or maintain the switching means 18, in particular the associated safety output, in a passive state.

[0164] Conversely, if during the monitoring period the difference between the numerical values ​​of the image characteristic F compared by the SPU 28 remains below the safety threshold, the SPU 28 determines a safety situation and is preferably configured to drive the switching means 18, in particular the associated safety output, to an active state.

[0165] Preferably, the IPU 26 and the two SPUs 28 are part of the same data processing board 27 .

[0166] According to one aspect of the invention, the control unit 16, in particular the two SPUs 28, are configured to monitor / control the operation of the imaging means 14 and are thus able to detect malfunctions.

[0167] Preferably, the control unit 16 may be configured to perform diagnostic procedures to determine malfunctions of the imaging means 14 .

[0168] In particular, the control unit 16 is preferably configured to modify the operation of the image capture means 14 at a time t in order to cause the image capture means 14 to produce an expected capture result at the time t and to compare whether the actual capture result at the time t by the image capture means 14 matches the expected capture result.

[0169] For example, the control unit 16 may be configured to perform a diagnostic procedure that involves switching off the imaging means 14 for a predetermined time interval and checking the response to determine whether a fault exists.

[0170] During this diagnostic procedure, if the electronic control unit 16 does not receive the digital image D when the imaging means 14 is switched off and receives the digital image D again after the imaging means 14 is restarted, the electronic control unit 16 determines that the imaging means 14 is in normal operation, otherwise the electronic control unit 16 determines that the imaging means 14 is faulty and places or maintains the switching means 18 in a passive state.

[0171] More particularly, preferably during such a diagnostic procedure, the SPU 28 is configured to switch off the image acquisition means 14. Preferably, the IPU 26 is configured to provide an error signal to the SPU 28 regarding the absence of an image provided by the image acquisition means 14. The SPU 28 is then preferably configured to determine that operation of the image acquisition means 14 is correct upon receiving the error signal from the SPU 28 when switching off the image acquisition means 14.

[0172] If the electronic control unit 16 determines that the imaging means 14 has failed, it is configured to prevent the machine 101 from starting by placing or maintaining the switching means 18 in a passive state.

[0173] The technical effect associated with the implementation of such a diagnostic test relates to the fact that it is possible to use a single optoelectronic image acquisition device 20, in particular a single camera, also in a safety device for the functional safety of the system 100. In particular, the ability to determine possible failures of the image acquisition means 14 in real time makes it possible to avoid the need to use at least two mutually redundant cameras without jeopardizing the security level of the device 1. In particular, this diagnostic procedure makes it possible for the device 1 to achieve a functional safety level or SIL (Safety Integrity Level) of 3 in accordance with the IEC 61508:2010 standard even with a single optoelectronic image acquisition device 20, in particular a single camera, with obvious advantages as explained below.

[0174] According to a further aspect of the present invention, the electronic control unit 16 is preferably configured to determine whether the device 1 has been tampered with relative to its initial installation configuration and / or to determine environmental conditions that affect the operation of the device 1.

[0175] Furthermore, the electronic control unit 16 is preferably configured to determine any acquisition conditions that impair the proper functionality of the device 1, such as fog, smoke, water or ice on the housing 3, excessively high or low light levels, the presence of intervening objects between the device 1 and the monitoring area, etc., and to maintain the switching means 18 in a passive state if necessary.

[0176] For example, in one possible non-limiting embodiment, the electronic control unit 16 may be configured to determine the noise level present in the digital image D acquired by the imaging means 14. If the noise level is below a predetermined minimum value, the electronic control unit 16 determines that there has been tampering with the device 1, e.g., due to occlusion of the imaging means 14, and keeps the switching means 18 in a passive state. Furthermore, the electronic control unit 16 may be configured to acquire and store a digital reference image D of the monitored area.

[0177] Furthermore, in use, the electronic control unit 16 may be configured to determine changes in installation or environmental conditions that affect the correct functioning of the device 1 by comparing the acquired digital image D with a reference digital image acquired during an initial installation phase, and to maintain the switching means 18 in a passive state if necessary.

[0178] Referring to the example shown in FIG. 3, the device 1 may also be configured to be connected in series with other devices 1.

[0179] More specifically, the device 1 may have at least a pair of safety inputs 31 that are connected to the electronic control unit 16 of the device 1 and configured to be connected to respective safety outputs of other devices 1.

[0180] Preferably, each safety input 31 is connected to an associated SPU 28 so as to provide a signal output from an associated safety output of another device 1 as an input to the SPU 28 .

[0181] Furthermore, each SPU 28 is preferably configured to drive its associated switching means 18 to the active state only if the logic state of the signal provided by its associated safety input 31 is also "ON" or "1", indicating that the other device 1 has also determined a safety situation. Otherwise, the SPU 28 is preferably configured to drive its associated switching means 18 to the passive state.

[0182] Referring to the example shown in FIG. 3, preferably the device 1 further comprises a light source 32 electrically connected to the electronic control unit 16 and configured to output a light signal based on, for example, the state of the switching means 18.

[0183] In particular, the light source 32 may comprise an LED (Light Emitting Diode), especially an RGB LED.

[0184] The electronic control unit 16 may be configured to control the light source 32 to output a light signal of a first color when the switching means 18 is in an active state and to output a light signal of a second color when the switching means 18 is in a passive state.

[0185] Referring to FIG. 2, preferably, the housing 3 comprises a transparent or translucent portion 33 positioned over the light source 32 so that the light signal emitted by the light source 32 is visible to the operator.

[0186] Referring to the example shown in FIG. 3, preferably the device 1 further comprises an acceleration or inertial sensor 34 electrically connected to the electronic control unit 16 .

[0187] Preferably, the acceleration sensor 34 is a three-axis accelerometer.

[0188] Preferably, the electronic control unit 16 is configured to determine vibrations of the device 1 based on the signals provided by the acceleration sensor 34 and to put or keep the switching means 18 in a passive state if these vibrations exceed a predetermined tolerance threshold.

[0189] Furthermore, the device 1 preferably comprises a temperature sensor 36 electrically connected to the electronic control unit 16 .

[0190] Preferably, the electronic control unit 16 is configured to determine the temperature of the device 1 based on the signal provided by the temperature sensor 36 and to place or maintain the switching means 18 in a passive state if this temperature is outside a predetermined range.

[0191] Referring to the example shown in Figure 3, the device 1 further comprises a storage means 38 electrically connected to the electronic control unit and configured to store images / data captured by the imaging means 14 and / or data relating to the operation of the device 1 itself.

[0192] More specifically, the storage means 38 may comprise a removable electronic memory card or the like.

[0193] Preferably, the device 1 further comprises a power port 40 configured to be connected to a power source for powering the device itself.

[0194] Referring to FIG. 3, preferably, the device 1 further comprises a communication interface 42 for electrically connecting an electronic device separate from the device 1, such as a personal computer and / or a tablet, to the electronic control unit 16.

[0195] For example, the communications interface 42 allows the electronic control unit 16 to be connected to a computer having a program or GUI (graphical user interface) installed thereon, which allows a user to configure the operation of the electronic control unit 16.

[0196] The operation of the above-described optoelectronic safety device 1 and associated system 100 according to the present invention is as follows.

[0197] Once the device 1 is positioned so that the field of view of the imaging means 14 includes the monitoring area A, operation of the device 1 preferably begins with an initial calibration procedure or setup to adjust the operating parameters of the device 1 based on the installation position of the device 1.

[0198] Preferably, the initial calibration procedure of the device 1 includes the following steps: a) Place the calibration target 200 on the reference surface. b) The imaging means 14 is controlled to capture an image of the calibration target 200 . c) Obtaining a transformed digital image D relative to the reference plane R from the digital image D by calculating a transformation matrix, i.e., a projection matrix or homography matrix.

[0199] According to one aspect of the present invention, preferably the initial calibration procedure further comprises the step of defining a masking region M of the digital image D.

[0200] Preferably, the initial calibration procedure may include changing further operating parameters of the device 1, such as for example the length of the monitoring period.

[0201] It is understood that the above-described initial calibration procedure does not need to be repeated every time the device 1 is started up. For example, it is sufficient to perform this calibration procedure only once after the device 1 has been positioned and / or after the installation conditions of the device 1 have changed.

[0202] Furthermore, instructions for carrying out the initial calibration procedure may be stored in a computer program, and the electronic control unit 16 may be configured to automatically execute these instructions upon command.

[0203] On the other hand, preferably, the general operation of device 1 includes monitoring monitoring area A for a monitoring period by activating device 1, and enabling operation of machine 101 by driving switching means 18 of device 1 to an active state only if it is determined that a safe situation exists.

[0204] Furthermore, if device 1 is compatible with system 100 which further includes device 108 corresponding to entrance / exit 103, activation of device 1 is preferably performed after the access control function is activated by device 108 at entrance / exit 103.

[0205] More specifically, in the initial operating state of the device 1, the electronic control unit 16 preferably inhibits operation of the machine 101 by causing or maintaining the switching means 18 in an inactive state.

[0206] Furthermore, the operation of the device 1 includes the following steps. d) receiving an instruction to activate the imaging means 14; e) By operating the imaging means 14 over a monitoring period, a number of digital images D of the monitoring area are acquired. f) Providing digital images D to the electronic control unit 16 during the monitoring period. g) Checking that the electronic control unit 16 determines the dangerous situation based on the digital image D provided by the imaging means 14. h) Preventing the start of the machine 101 if a dangerous situation is determined, or vice versa. i) If it is determined that no dangerous situation exists, the machine 101 is permitted to start.

[0207] For example, step d) may include receiving a signal from the same device 108 and / or from the electronic control unit 118 of the system 100 which may activate the imaging means 14 of the device 1 when the safety door 103 is closed and locked via the device 108.

[0208] Preferably, step g) comprises calculating, by the IPU 26, a value of an image characteristic F of the digital image D received from the imaging means 14.

[0209] More particularly, step g) preferably comprises correcting for distortions introduced by the optical system 22 to the digital image D, ie performing a "fish-eye" correction.

[0210] Furthermore, step g) preferably comprises transforming the digital image D relative to a reference plane R.

[0211] More particularly, step g) preferably comprises determining a transformed digital image D relative to the reference plane R by multiplying / combining the digital image D with a projection matrix or homographic matrix determined during the initial calibration step.

[0212] Furthermore, step g) preferably includes determining, based on a masking region defined during the initial calibration, a portion of interest of the digital image D that will be processed to determine the numerical value of the image characteristic F.

[0213] Additionally, step g) preferably includes determining the numerical values ​​of the image characteristic F from the transformed digital image D, providing these numerical values ​​to the two SPUs 28, and ensuring that the two SPUs 28 determine the difference between these numerical values ​​of the image characteristic F.

[0214] Further, during step g), each SPU 28 determines whether the difference between these values ​​of image characteristic F exceeds a safety threshold, thereby determining a safe or unsafe situation and inhibiting or not starting machine 101.

[0215] The advantages associated with the optoelectronic safety device 1 according to the invention, its method of operation and a safety system comprising this device are clear.

[0216] First, the use of the device 1 significantly increases the safety level of the facility 100, because it reduces the risk of the machine 101 being started while a person P is accidentally trapped inside the protective wall 102.

[0217] Furthermore, the ability to connect multiple devices 1 in series avoids blind spots within the protective wall that are not monitored by the devices 1, thereby improving the safety level even in large-scale facilities 100 or facilities 100 equipped with machines 101 with complex shapes.

[0218] Additionally, the unique architecture of Device 1 allows for reduced implementation costs as only one camera is used.

[0219] Furthermore, the use of the calibration target 200 greatly simplifies the initial calibration procedure for the user, who only needs to place the calibration target 200 on the floor and begin the calibration procedure.

[0220] Furthermore, being able to track the masking area M minimizes the risk of false positives, since it is possible to exclude from the monitoring area areas in which there may be moving objects or people in the field of view of the device 1 that are not related to a real dangerous situation, such as for example slightly swaying objects and / or people moving outside the safety perimeter.

[0221] Furthermore, the initial setup of the device 1 is simple and can be performed by a non-highly skilled person, since it only involves placing the calibration target 200 on the reference surface R and providing instructions to start the initial calibration procedure, without any other operator intervention.

[0222] Furthermore, during the calibration procedure, the operator can instantly visually check the images acquired by the device 1 via the GUI.

[0223] Finally, the use of the IPU 26 and two separate and independent SPUs 28 allows the performance of the individual electronic boards, and therefore their cost, to be optimized according to their actual use. Image processing operations requiring higher computational power are in fact relegated exclusively to the IPU 26, which must be sized accordingly. On the other hand, the SPU 28 performs the computational operations for determining safety situations based on image characteristics received from the IPU 26, which require less computational power.

[0224] Finally, it is evident that modifications and variations may be made to the optoelectronic safety device 1 according to the invention, to the method for its operation and to the safety system comprising said device without departing from the scope of protection defined by the claims.

[0225] For example, IPU 26 may be configured to provide different values ​​of image characteristic F to two SPUs 28 .

[0226] In particular, the IPU 26 can be configured to provide a numerical value of a first image characteristic F1, such as color centroid, to the first SPU 28, and a numerical value of a second image characteristic F2, such as grayscale, to the second SPU 28.

[0227] Additionally, each SPU 28 may be configured to compare the received values ​​of the relative image characteristics F1 and F2 to determine the safety status of one independently of the other.

[0228] Furthermore, referring to the schematic example shown in FIG. 5, the IPU 26 may be configured to provide two SPUs 28 with numerical values ​​of an image characteristic F obtained from digital images D captured at different times.

[0229] For example, IPU26 is acquired at time t n The first SPU 28 receives the image characteristic F calculated from the digital image D acquired at the acquisition time t (n+1) The second SPU 28 may be configured to provide a value of an image characteristic F calculated from a digital image D acquired at t (n) and t n+1 correspond to different acquisition times.

[0230] Furthermore, with reference to a further variation shown schematically in Figures 6 to 10, the IPU 26 can be configured to calculate a difference Q between two or more previously acquired digital images D and provide to the SPU 28 a numerical value of an image characteristic F calculated from the difference Q between the two or more digital images D.

[0231] In particular, referring to the example shown in FIG. 6, the IPU 26 may take two consecutive acquisition times t (n)(-1) and t n and supplying the feature values ​​calculated from the difference between the two digital images D to both SPUs 28.

[0232] For example, Figures 8, 9, and 10 show the time t (n)(-1) A digital image D of a person P is acquired at time t after the person P moves, for example, by one step. n A digital image D of a person P taken at t n and t n-1 1 and 2 show a schematic representation of the difference Q calculated between two digital images D acquired at two points in time.

[0233] For clarity, in Fig. 10, the difference Q is displayed in a negative for clarity, i.e., the portion corresponding to the difference Q is displayed in an inverted color in Fig. 10 compared to the colors used for each portion of person P in Figs. 8 and 9.

[0234] Figures 11, 12, and 13 show the time series at two different times t (n-1) and t n 11, 12, and 13 show two digital images D and their difference Q taken at different times, respectively, but the displacement of person P between these two different images is smaller than the examples shown in Figures 8-10. For example, the displacements shown in Figures 11, 12, and 13 may be below a safety threshold.

[0235] 7, the IPU 26 may be configured to calculate a first difference Q1 between two digital images D captured at first two capture times, and provide a value of an image characteristic F calculated from the difference Q1 to the first SPU 28. The IPU 26 may be configured to calculate a second difference Q2 between two digital images D captured at second two capture times, and provide a value of an image characteristic F calculated from the difference Q2 to the second SPU 28, where the second capture times are different from the first capture times.

[0236] Further, with reference to the example shown in FIG. 11, the safety system of the plant 100 may comprise a number of optoelectronic safety devices 1 connected in series with each other.

[0237] Additionally, the initial calibration procedure of device 1 may include alternative methods for calculating the homographic or projective transformation matrix.

[0238] For example, instead of using a calibration target 200 placed on the reference surface R, the electronic control unit 16 may be configured to receive, for example from an operator, coordinates of the position at which the device 1 is placed relative to the reference surface R, and to calculate this transformation matrix based on the coordinates indicated by the operator.

[0239] Additionally or alternatively, the electronic control unit 16 may be configured to determine at least some of the coordinates of the position at which the device 1 is installed, such as the orientation of the device 1 relative to the reference plane R, based on data provided by the acceleration sensor 34. [Explanation of symbols]

[0240] 1 Optoelectronic safety devices 3. External housing, enclosure, casing 5. Bass 6 Lid 8 Gaskets 9. Transpiration element or membrane 10 Anchor bracket 10a First end 10b Second end 12 joints 14 Imaging means, image capture means, image acquisition means 15 Transparent or semi-transparent areas 16 Electronic Control Unit 18 Switching Methods 20. Optoelectronic imaging device, optoelectronic image acquisition device 22 Optical system or lens 24 Photoelectric Sensor 26 Image Processing Unit (IPU) 27 Data Processing Board 28 Secure Processing Unit (SPU) 31 Safety Input 32 light source 33 Transparent or semi-transparent areas 34 Acceleration or inertial sensors 36 Temperature Sensor 38 Memory means 40 power ports 42 Communication Interface 100 Industrial machinery or industrial equipment, systems, plants 101 Machinery 102 Protective Wall 103 Openings, entrances, passages, safety doors, gaps 104 Fixed part 105 Access opening 106 Moving parts 108 Electronically operated safety locking devices, apparatus, access control devices, 110 Safety Switch 112 Actuator 114 Sensor means 116 Switching Means 118 Electronic control units, control units, control devices 200 positioning targets, calibration targets A. Monitoring Area D Digital Image, Digital Reference Image, Transformed Digital Image F Image characteristics, image features / parameters, image characteristics / parameters / properties F1 First Image Characteristics F2 Secondary image characteristics M Masking area, masking part P person Q difference Q1 First Difference Q2 Second Difference R reference plane R1 lateral rotation axis R2 lateral rotation axis S1 safety signal X Area of ​​interest, part of interest

Claims

1. An optoelectronic safety device (1) for an industrial plant (100) having a machine (101) positioned within a predetermined monitoring area (A), comprising: imaging means (14) configured to capture a digital image (D) of said monitoring area (A); An electronic control unit (16), driving the imaging means (14) to capture the digital image (D); processing the digital images (D) to determine a hazard situation if movement associated with the presence of a person (P) and / or object located within the monitoring area (A) is determined during a monitoring period; Preventing the start of the machine (101) when the dangerous situation is determined, or vice versa; If the dangerous situation is not determined, the machine (101) is permitted to start. An electronic control unit (16) configured as follows: An optoelectronic safety device (1).

2. The electronic control unit (16) receiving a monitoring activation signal when the machine (101) is not in operation; 2. The device of claim 1, wherein, in response to the monitoring activation signal, the imaging means (14) is controlled to capture the digital image (D) over the monitoring period.

3. 3. The device of claim 1 or 2, wherein the electronic control unit (16) is configured to detect the movement of a person (P) and / or an object located within the monitoring area (A) from the difference between at least two digital images (D).

4. 4. The device of claim 3, wherein the electronic control unit (16) is configured to detect movement of a person (P) and / or object located within the monitoring area (A) from differences between image characteristics (F) obtained from at least two different digital images (D) and / or from differences between image characteristics (F) obtained from differences between two different digital images (D).

5. 5. The device of claim 4, wherein the electronic control unit (16) comprises an image processing unit (26), connected to the image acquisition means (14) and configured to process the digital image (D) to calculate numerical values ​​of one or more image characteristics (F) of the digital image (D).

6. the image characteristics (F) include at least one of color or grayscale value, average color or grayscale value, maximum color or grayscale value, lightness, color or grayscale centroid; 6. The device of claim 5, wherein the image characteristics (F) are calculated from the digital images (D) or from one or more portions of the digital images (D) and / or the image characteristics (F) are calculated from differences between at least two of the digital images (D).

7. 7. The device of claim 5 or 6, wherein the electronic control unit (16) further comprises a pair of safety processing units (28) connected to the image processing unit (26) and configured to receive the image characteristics (F) from the image processing unit (26).

8. 8. The device of claim 7, wherein the safety processing unit (28) is configured to compare the numerical values ​​of the image characteristics (F) for at least two digital images (D) and determine the presence of a person (P) or a moving object if the difference between the numerical values ​​of the image characteristics (F) or the numerical value of the image characteristic (F) itself exceeds a predetermined safety threshold.

9. 9. The device according to claim 5, wherein the image processing unit (26) is further configured to obtain a new transformed digital image (D) relative to a reference plane (R) by performing a projective or homographic transformation from the digital image (D).

10. 10. The device of claim 9, wherein the image processing unit (26) is configured to perform the projective transformation using a projective transformation matrix calculated from an image of a calibration target (200) positioned and / or projected onto the reference plane (R).

11. 11. A device according to any one of claims 1 to 10, wherein the imaging means (14) comprises only a single optoelectronic two-dimensional imaging device (20).

12. 12. The device according to any one of claims 1 to 11, wherein the electronic control unit (16) is configured to perform diagnostic procedures of the functioning of the imaging means (14).

13. 13. The device of claim 12, wherein the diagnostic procedure allows for modifying the operation of the imaging means (14) to produce an expected acquisition result by the imaging means (14) and compare whether the actual acquisition result by the imaging means (14) matches the expected acquisition result.

14. A method of operating an optoelectronic safety device (1) according to any one of claims 1 to 13, comprising: a) receiving an instruction to activate said imaging means (14); b) operating said image acquisition means (14) over said monitoring period to acquire a plurality of digital images (D) of said monitoring area (A); c) providing said digital image (D) to said electronic control unit (16); d) checking that the electronic control unit (16) determines the dangerous situation based on the digital image (D) provided by the imaging device (14); e) preventing the start-up of the machine (101) if the dangerous situation is determined, or vice versa; f) allowing the machine (101) to start if the dangerous situation is not determined; in that order.

15. A safety system for an industrial plant (100) comprising a machine (101) and a protective barrier (102), the protective barrier (102) defining a safety boundary within which the machine (101) is located and comprising an opening (103) giving access to the machine (101), an access control device configured to be associated with said doorway (103) and configured to detect and / or prevent access into said secure perimeter via said doorway (103) upon command; At least one optoelectronic safety device (1) according to any one of claims 1 to 13; A safety system comprising:

16. 16. The system of claim 15 when dependent on claim 2, wherein the access control device is further configured to transmit a safety signal when it does not detect and / or prevent access via the opening (103) within the safety boundary, the safety signal corresponding to the monitoring activation signal of the optoelectronic safety device (1).

Images