Lighting system for selectively adjusting lighting parameters for sub-areas of an overall illumination area and method for controlling the lighting system

Abstract

The invention relates to a method and lighting system for individually controlling illumination of a plurality of sub-areas commonly constituting an overall illumination area of a controllable light source. An environment sensor senses an environment at least corresponding to the overall illumination area and generates a representation thereof. A processing unit analyses the representation for determining objects and / or regions in the representation. The processing unit further sets a setting value for the at least one lighting parameter for each of the plurality of sub-areas depending on the determined object and / or regions, and a controlling unit controls light emission of the controllable light source according to the determined values for each of the plurality of sub-areas.

Description

[0001] Lighting system for selectively adjusting lighting parameters for sub-areas of an overall illumination area and method for controlling the lighting system

[0002] Description:

[0003] The invention regards a lighting system for selectively adjusting lighting parameters for subareas of an overall illumination area and a method for controlling the lighting system accordingly.

[0004] With modern lighting systems, it becomes more and more common to individually adjust illumination for certain illuminated areas according to the requirements of the respective area. In many cases, this is achieved by controlling luminaires to provide dedicated illumination properties, for example different brightness levels. Using a plurality of dedicated luminaires in combination allows roughly adjusting brightness for different areas by applying individual dimming levels for each luminaire. On the other hand, modern technology allows to selectively adjust setting values for lighting parameters within a single luminaire. For example, digitally controlled light sources, such as an LED matrix and light sources using DLP (digital light processing) technology, enable adaptation of a dimming level (brightness) individually for a plurality of areas within the overall illumination area of a single luminaire. Arbitrary light distribution can be achieved using one or more such digitally controlled light sources. However, this requires a cumbersome commissioning process in which the setting values for the sub-areas illuminated by such digitally controlled light source must be individually set for the specific situation in which such luminaire shall be used.

[0005] In outdoor scenarios path lights or streetlights are used. The overall illumination area results from a plurality of boundary conditions like for example height of the respective luminaire, number of heads, orientation, number of modules per head, and a lens of the respective head for projecting the light to be emitted. As it can easily be seen from the above description, this results in a complex procedure in case that a path light or a streetlight shall be adapted to a specific environment in which it is positioned. In any case, the resulting configuration is static and change of an environmental situation cannot be automatically reflected in the illumination pattern provided by a luminaire.

[0006] It is therefore desirable to provide a lighting system allowing dynamically adjusting for example light distribution within an overall illumination area. This object is achieved by the lighting system according to the present invention and the method for individually controlling illumination of a plurality of sub-areas of an overall illumination area.The lighting system according to the present invention comprises a controllable light source, environment sensing means, a processing unit and a control unit. The controllable light source allows to illuminate an overall illumination area. The overall illumination area is divided into a plurality of sub-areas and the controllable light source is able to set setting values for at least one lighting parameters for each of these sub-areas individually. By determining setting values for the at least one lighting parameter individually for different sub-areas it is therefore possible to generate an illumination pattern in which characteristics of illumination of the different subareas differ from each other. Thus, areas within the overall illumination area of the light source maybe illuminated using a higher dim level compared to other areas. Accordingly, in case that the overall illumination area covers, for example, a zebra crossing and in addition surrounding regions, which shall not need to be illuminated with bright light, it is possible to selectively increase the brightness only in the zebra crossing region.

[0007] According to the inventive lighting system, the determination of the setting values for the at least one lighting parameter for each of the sub-areas depends on determined objects and / or regions. Objects and / or regions that lie within the overall illumination area of the controllable light source are determined by analyzing a representation of the overall illumination area.

[0008] Environment sensing means generate a representation at least of the overall illumination area. It is to be noted that the environment sensing means may generate a representation of an even larger area compared to the overall illumination area. In such a case, the representation generated by the environment sensing means may not only be used for a single controllable light source as explained above but also for further controllable light sources. On the other hand, the environment sensing means may even comprise a plurality of separate units and information obtained by these units is combined for generating the representation at least of the overall illumination area. For example, environment sensing means may comprise at least a camera capturing an image of a scene as representation. Such representation may even be a combination of captured images of a plurality of separate units like a plurality of cameras using commonly known image processing technology.

[0009] The representation generated by the environment sensing means is then analyzed by the processing unit using conventional image processing technology. Examples for such technologies are edge recognition, object determination, segmentation et cetera. The analysis of the representation may use Al, deep learning algorithms, neural networks and other methods known in the art. For the present invention however, it is important that the analysis of the representation obtained by the environment sensing means provides information on objects, regions, and relations between objects and / or regions.The processing unit then determines from the analysis result and, thus, the respectively determined objects and / or regions in the representation, setting values for the at least one lighting parameter for each of the plurality of sub-areas. Based on the determined setting values, the control unit controls light emission of the controllable light source.

[0010] With the present invention, it is possible to determine for an overall illumination area of a controllable light source whether there are objects and / or regions for which a predetermined illumination shall be provided. For the explanations herein, it is mostly referred to brightness as lighting parameter, because this allows easy understanding of the present invention. However, it is evident that the invention may also be applied to individually controlling other lighting parameters, for example color temperature or color.

[0011] The specific advantage of the present invention is that, based on a representation of the environment in which illumination shall be achieved using the controllable light source, objects and / or regions that are of interest can be identified and corresponding setting values for the lighting parameters can be determined. For example, the system may increase brightness in an area in which the zebra crossing is identified but reduce the light intensity for areas in which only grass can be recognized. The association between the desired setting value for the lighting parameter and the determined object and / or region maybe predefined. For example, an association table may be stored in a memoiy of the system. Once an object and / or region is determined based on the representation, the associated setting value for the lighting parameter can be identified and the light source can be controlled accordingly. As a result, illumination of the zebra crossing can be achieved with a higher light intensity compared to other regions like areas in which grass or trees or other plants have been determined.

[0012] Controlling the controllable light source based on an analysis of the representation allows to easily and dynamically adapt lighting characteristics within the overall illumination area even to changing conditions. For example, in case that construction work is going on in a part of the overall illumination area, this may also be automatically recognized based on the analysis of the representation, and setting values can be adjusted automatically.

[0013] According to preferred embodiment, the processing unit is further configured to determine corresponding areas by mapping one or more sub-areas on locations of objects and / or regions determined in the representation. The sub-areas commonly constituting the overall illumination area corresponds to different locations within the overall illumination area. Thus, according to the preferred embodiment, each of the sub-areas is mapped on an object and / or a region identified to lie within the overall illumination area. Thus, for each of the sub-areas, the setting value can be determined based on the respectively determined object and / or region that wouldbe illuminated when the dimming level for the respective sub / area is greater than zero.

[0014] Preferably, the overall illumination area is divided into at least 32x32 sub-areas arranged in a rectangular structure. The overall illumination area may also be rectangular and divided into, for example, 256x64 sub areas. Examples for controllable light sources allowing to illuminate an overall illumination area with such a grid of sub-areas are an LED matrix or a DLP light source. Of course, other controllable light sources with fixed segments corresponding to the sub-areas having a non-rectangular structure may also be thought of.

[0015] In an ideal situation, the optical axis of the environment sensing means and the optical axis of the controllable light source are identical. In case that there is a major difference of the optical axes, a mapping of the representation onto the sub-areas is done using transformation information, which is produced in a calibration process. In such a calibration process, locations in the representation of the overall illumination area are mapped to sub-areas of the controllable light source. Accordingly, for objects that are determined in the representation the location of the object in the representation is known and the corresponding sub-areas can be identified using the transformation information.

[0016] Preferably, the system comprises a memoiy storing a reference set of setting values. The reference set of setting values may be for example a set of setting values determined for a reference representation. Such reference representation may be an initially generated representation (when setting the lighting system into operation) or a representation generated in an (almost) ideal situation in the overall illumination area. The reference representation may also be manually processed based on an initially generated representation derived from the environment sensing means. In such a manually adapted reference representation, a system operator may for example define certain regions, thereby even enabling determination of objects and / or regions in the representation which cannot automatically be determined from the analysis of the representation by the processing unit.

[0017] The system may preferably comprise a memory storing such a reference representation and / or an analysis result of such reference representation.

[0018] The lighting system according to the invention may comprise a memoiy storing setting value information associated with objects and / or regions identifiable in the representation. Storing such predefined association in a memory of the lighting system allows automatically determining the setting values required for controlling the controllable light source upon detection of objects and / or regions in the representation by the processing unit.The memory for storing the reference representation, for storing a reference set of setting values, and for storing setting value information may be one common memory or comprise a plurality of dedicated memories.

[0019] Preferably, the processing unit is configured to adapt the setting values for the at least one lighting parameter for a corresponding area in response to a confidence value for recognition of the object and / or region corresponding to this corresponding area. As explained above, subject areas in the overall illumination area are mapped to objects and / or regions identified in the representation of the overall illumination area. The determination of the objects and / or regions in the overall illumination area can only be determined with a certain level of confidence. The algorithms providing the determination results typically provide information on such confidence of a determined object and / or region. According to the invention, it is now possible to adjust, depending on the confidence level of an object and / or region, the lighting intensity or another lighting parameter. In case that the confidence level for the recognition of an object, for example, falls below a threshold, it is possible to increase the light intensity for the sub-areas corresponding to this object in order to provide improved illumination of the object determined with an unsatisfying confidence level. Such increase of brightness for the sub-areas corresponding to the presumably determined object increases the likelihood that object recognition with improved confidence is possible from the analysis of the representation. It is also possible to stepwise increase the light intensity until a threshold for the confidence is reached. Providing an increased light intensity in line with above described procedure, improves the probability that other objects in this area can be identified correctly.

[0020] This adjustment of the setting value of a lighting parameter may for example be made relative to the setting values for a reference representation. It is assumed that such reference representation is generated under optimized boundary conditions such that the resulting set of setting values is based on object and / or region determination with sufficient likelihood or confidence.

[0021] In order to improve lighting conditions for sensing the environment with the environment sensing means in order to generate a high-quality representation, it is preferred to use an auxiliary light source for illuminating the overall illumination area. This auxiliary light source may be a light source for infrared light. Such auxiliaiy light source for illuminating the overall illumination area has the advantage that the representation based on which the determination of objects and / or regions in the overall illumination area is performed, is provided with an enhanced quality. Accordingly, the analysis may be performed with improved quality, too.According to a further improved embodiment of the present invention, the lighting system comprises a terminal device and / or a server that are connectable to the processing unit. Using such terminal device and / or server connected to the processing unit allows to visualize the representation or the result of the analysis of the representation to an operator of the lighting system. Connecting the processing unit to a server even enables to store representation generated over time in order to perform an analysis on changes over time. For example, in case that trees grow and cause shadows in a region that is required to be well illuminated by a street lamp, this can be identified from a comparison of representations at different instances of time. The system may also provide an automated alert function, which, in response to identifying such changes in the environment of the lighting system, informs the operator or even other organizations in charge.

[0022] On the other hand, the terminal device and or the server connected to the processing unit enable an operator of the lighting system to adjust the representation generated by the environment sensing means and / or adjust the result of the analysis of the representation, for example, by revising the object and / or region recognition performed by the processing unit. The revised representation is then provided to the processing unit that, in response to receiving such revised representation, determines the setting values in the same way as explained above but based on the revised representation.

[0023] The possibility to manually revise the representation and / or the analysis result of the representation has the advantage, that an operator may even add information to the representation which cannot be automatically determined by the processing unit. According to one preferred embodiment, it is even possible to define a region of interest within the representation initially generated by the environment sensing means. For example, in case buildings are determined within the representation, areas corresponding to such buildings may be identified by an operator and further determination of objects these regions may be suppressed for analysis of future representations. Objects like buildings usually do not change for a long period of time and, thus, it is unnecessary to repeat object recognition in these regions for every new representation generated by the environment sensing means.

[0024] The method according to the present invention is performed by the lighting system explained above. With this method, it is possible to individually control illumination of a plurality of subareas commonly constituting an overall illumination area. First, the environment, in which the overall illumination area lies, is sensed by environment sensing means. The environment sensing means generate a representation of the environment including at least the overall illumination area. This representation is then analyzed for determining objects and / or regions in the representation and, thus, in the overall illumination area. Setting values for each of theplurality of sub-areas for the at least one lighting parameter are determined based on the recognized objects and / or regions. Based on these setting values, light emission of the controllable light source is then controlled in order to illuminate the plurality of sub-areas in response to determined objects and / or regions in the representation.

[0025] According to a preferred embodiment, the generation of a representation, analysis of the representation and determination of the setting values is repetitively executed. The repetitive execution can be performed in line with a predefined time schedule. Alternatively or in addition, the repetitive execution is performed upon reception of the trigger signal, or in response to determination of changes in the representation and / or change of the analysis result of the representation, wherein the repetition is made only in case that the change in the representation and / or the change in the analysis result is less than a first predefined amount. In addition or alternatively the steps mentioned above are repeated in case that the changes in the representation and / or the changes in the analysis result exceed a second threshold only in case that the determined change remains for a predefined time interval.

[0026] Repeating the evaluation of a new representation which is generated based on actual information received from the environment sensing means allows to accomplish for changes such as seasonal changes, automatically. On the other hand, in case changes to the environment are known to an operator of the system, it is also an advantage that the system may be triggered by the operator to reevaluate a new representation and to determine an actual set of setting values at any desired point in time.

[0027] On the other hand, it is an advantage to automatically determine whether changes in the representation and / or changes in the analysis result are only minor changes. In case of such minor changes, it is assumed that the environmental situation only slowly changes, which is considered to be an evolution and which may, for example, result from seasonal changes. One possible change for example is that trees may have leafs during summertime but no leafs during winter time. Such slow and minor changes may automatically be considered by an automated determination of respectively changed setting values. On the other hand, in case the changes determined in the representation or in the analysis result of the representation, an adaptation is only performed when these changes remain at least for a certain period of time. This allows to avoid a high frequency of illumination changes which are caused by temporary changes to the environmental situation. Such a temporary change might be caused for example by a lorry parking on a road or partially on the pavement. On the other hand, changes that may last for at least a plurality of days, for example, may be considered in order to adjust the setting values. This allows to automatically take account of longer lasting changes in the overall illumination area like for example, a construction site established in the overall illumination area.It is further preferable that a default set of setting values is loaded in case that determination of objects and / or regions in the representation is ambiguous. The situation in which the determination of objects and / or regions in the representation is ambiguous may for example be determined from confidence values that are provided by the algorithm determining objects and / or regions in the representation. The confidence value (or similarly the likelihood) may considered to reflect an ambiguous determination in case that the confidence value falls below a certain threshold. The threshold may be adjustable. Storing and using such a default set of setting values has the advantage that light distribution patterns are avoided which must be considered to be not reasonable. Thus, in case that the automated determination of setting values is irritated by misleading analysis results, it is preferred to use a default set of setting values. Such a default set of setting values can either be determined during configuration of the system automatically based on an analysis result under ideal (or optimized) conditions or even based on a revised representation in which an operator of the system added information on objects or areas of interest.

[0028] It is furthermore preferred that setting values may at least be partially adapted in response to predefined characteristics of determined objects and / or regions. Such an adaptation allows to take into account further characteristics and features of determined objects and / or regions which may influence the requirement regarding the illumination of the respective object and / or region. For example, in case that a pavement identified in a representation is determined to be relatively bright, a lower dim level may be used as a setting value for the parameter "brightness" for sub-areas corresponding to this bright pavement compared to a pavement which is determined to be relatively dark. Taking into account such additional characteristics of the determined objects and / or regions in the representation allows to reduce energy consumption required for sufficiently illuminating an area as much as possible without making a compromise with respect to safety aspects.

[0029] It is further preferred that the processing unit adapts the setting values for the at least one lighting parameter for a corresponding area in response to a confidence level for recognition of the object and / or area. An adaptation of the setting values in response to a confidence level for the determination of an object and / or region in the representation allows to improve illumination of the respective sub-areas corresponding to the object (region) which is likely to be determined and thereby to improve the likelihood that in a new representation made under the improved illumination conditions, the confidence for correct recognition of an object (region) may be increased. It is to be noted, that such adaptation may not be strictly limited to the subareas corresponding to an object (region) likely to be determined in the representation, but theadaptation may be extended to surrounding sub-areas, which may specifically improve results achieved when edge recognition is applied for the analysis of the representation.

[0030] For the same reason the brightness (or dim level, light intensity) may be increased in order to improve illumination at least for illuminated sub-areas, during generation of a new representation. This is particularly advantageous in case new representations have to be generated at times in which natural illumination of the area is critical. For example, it might be necessary to generate a new representation during nighttime in which no natural light is available for illuminating the area for which the representation shall be generated. On the other hand, even in case that representations are generated using daylight, increased brightness may be advantageous in order to reduce effects like shadows caused by sunlight. The increase of the brightness when generating a new representation may even be decided based on an analysis of a previous representation. For example, negative influences such as shadows might be determined from a previous representation. In response to recognizing such critical illumination situation, sub-areas lying in a shaded region could be specifically illuminated.

[0031] According to a further preferred embodiment, at least one of the result of the analysis of the representation and the correspondingly determined setting values of the at least one lighting parameter is output for monitoring. Specifically in combination with a server connectable to the processing unit, it is possible to store the result of the analysis of the representation and / or the determined setting values for later analysis. Such later analysis allows to detect abnormal changes either in the representation or in the setting values and countermeasures may be initiated by an operator of the system.

[0032] A preferred example of the lighting system according to the present invention will now be explained with reference to the enclosed drawings in which

[0033] Figure 1 shows a schematic of a lighting system according to a preferred embodiment of the invention, and

[0034] Figure 2 shows a simplified flowchart illustrating the major method steps for controlling a controllable light source in line with the present invention.

[0035] Figure 1 shows a schematic illustrating the major components of the lighting system 1 according to an embodiment of the present invention.

[0036] The lighting system 1 comprises a luminaire 2 including a controllable light source 3. According to a preferred embodiment, the light source 3 is a digitally controllable light source, like, for example an LED matrix or a DLP projector. Light emission of the controllable light source 3 isbased on signals received by the controllable light source 3 from a control unit 4. The control unit 4 generates control signals based on which sub-areas SA can be individually illuminated according to respectively determined setting values for each sub-area SA.

[0037] The entirety of sub-areas SA that can be illuminated by the controllable light source 3 constitute an overall illumination area OIA. It is to be noted that in the illustrated embodiment only a single line of sub-areas SA is shown in order to keep the illustration simple and easy to understand. However, it is evident that a matrix, for example, a square consisting of 32x32 subareas SA constitutes a typical overall illumination area OIA.

[0038] The luminaire 2 furthermore comprises a camera 5 as environment sensing unit in the preferred embodiment. In the illustrated embodiment, a single camera 5 is used and directly included in the luminaire 2. However, the invention may also use an external camera or other environment sensing means or even a combination of different types of sensing means. For example, information obtained from an image captured by a camera may be enhanced by merging additional information obtained from a radar sensor, an ultrasonic sensor, or a LIDAR sensor.

[0039] For explanation of the present invention, only the camera 5 will be considered hereinafter in order to generate a representation of the environment by capturing an image. The camera 5 has an optical axis OAc, and a field of view FOV, position and orientation of the camera 5 are chosen such that the field of view FOV covers the overall illumination area OIA as it can be seen in figure 1.

[0040] According to a preferred embodiment, the luminaire 2 comprises the controllable light source 3 and the camera 5, and the camera 5 and the controllable light source 3 are arranged such that the optical axes OAc of the camera 5 and OALS of the controllable light source 3 coincide or are at least so close to each other that the distance between the axes OAc and OALS only causes negligible effects. However, usually the effects of the distance between the axes OAc and OALS are not negligible and in that case calibration of the system is required in order to achieve a correct mapping of the representation and the sub-areas in the image plane. This is particularly important for cameras positioned with greater distance to the luminaire, for example, in case such external camera shall generate a representation for a plurality of luminaires.

[0041] A representation of the environment of the luminaire 2 is provided by the camera 5 to the processing unit 6. In the processing unit 6, the representation provided by the camera 5 is analyzed by using commonly known algorithms in order to determine objects and / or regions in the representation. Only as an example, an object 15 is shown within the overall illumination area OIA which is a part of the field of view FOV of the camera 5.Based on the determined objects and / or regions in the representation provided by the camera 5, the processing unit 6 determines a set of setting values for the lighting parameters that can be controlled by the controllable light source 3. In addition to the most important aspect of light intensity which is controlled by setting a desired dimming level for each sub-area SA, other lighting parameters for which setting values may be determined are: color or color temperature.

[0042] According to preferred embodiment, the overall illumination area OIA comprises 32x32 subareas and for each of these sub-areas, a setting value for each controllable lighting parameter is set. In case that only brightness of the sub-areas shall be adjusted, this means that for each of the 32x32 sub-areas a respective dimming level is set.

[0043] This set of 32x32 dimming level values is a set of setting values, and the set of setting values is supplied to the control unit 4. Based on the set of setting values, the control unit 4 then controls light emission of the lighting source 3 for illuminating the sub-areas SA.

[0044] It is to be noted that only for reasons of illustrating the procedure of determining control information for the controllable light source 3, a dedicated processing unit 6 and a dedicated control unit 4 are shown in the drawing. However, the processing unit 6 and the control unit 4 may also be integrated in a single processing module or processor. All functions now explained with reference to the processing unit 6 and the control unit 4 are then performed by such processing module or processor.

[0045] The processing unit 6 and the control unit 4 are connected to a memory 7. In the memory 7 information for executing operation in line with the present invention is stored. In particular, the memory 7 may store mapping information allowing to transform size and position of an object identified in the representation provided by the camera 5 into corresponding sub-areas SA. As an example shown in figure 1, an object 15 lies in the overall illumination area OIA. A plurality of sub-areas SA indicated by being hatched in the figure indicate these corresponding sub-areas SA. Thus, corresponding sub-areas SA in the sense of the present invention are those sub-areas SA illuminating (only) the object 15 when the dimming level for these sub-areas SA is greater than zero. Due to the limited number of sub-areas, it is obvious that the edges of the object 15 only roughly coincide with the outer edges of the corresponding sub-areas SA.

[0046] Only for completeness of explanation, the major components of the controllable light source 3 are shown in figure 1. In particular, the controllable light source 3 may comprise an LED matrix 11, which, in line with the explanations for the illustrated embodiment, is constituted of a matrix of 32x32 LEDs, each LED corresponding to one of the sub-areas SA. Light emitted by the LED matrix 11 is projected by a projector lens 12 to illuminate the overall illumination area OIA. TheLED matrix 11 is driven by a driver module 13, driving the respective LEDs in the LED matrix 11 based on the control signal received from the control unit 4.

[0047] The memory 7 may hold information regarding the association between types of determined objects and / or regions and the respective setting values for the lighting parameters. For example, in case that the region in the representation for which an image is captured by the camera 5 is identified as a grass region, the associated setting value for the region type “grass” may be zero for the diming level. Sub-areas SA in the overall illuminated area OIA corresponding to the grass region are then controlled to light emission “o”, resulting in no illumination of the grass. Contrary, in case that a region within the representation is identified as zero crossing, it is important that traffic participants can easily recognize a pedestrian when approaching the zebra crossing. Accordingly, the information hold in the memory 7 associates are setting level of, for example, 100% dimming level for the region type “zebra crossing” and sub-areas SA corresponding to a determined zebra crossing region are illuminated with the maximum possible light emission. It is also possible that for safety relevant regions like the zebra crossing or an intersection, the region illuminated according to the associated setting level is extended to ensure that, for example, a pedestrian is already visible when approaching the zebra crossing.

[0048] Since information for the setting values is stored in association with the determined or potentially determined type of objects and / or regions in the representation provided by the camera 5, the illumination provided by the controllable light source 3 is automatically adjustable in response to a new representation of the overall illumination area OIA provided by the camera 5 at a later point in time. Obviously, a region identified to be a zebra crossing region is a static region. However, other objects or regions may slowly develop over time like for example a tree or a bush. But even with respect to static objects like for example the zebra crossing region, the invention provides the great advantage that all luminaires may be built identically and, when mounted in their final position, the luminaires can automatically adapt to their specific illumination situation. This means, 2 neighboring streetlights can be of identical structure. Nevertheless, the one for which a zebra crossing region can be determined from the representation covering its overall elimination area OIA can automatically increase brightness for illumination of the zebra crossing region. Contrary, the neighboring streetlight without such zebra crossing but a relatively large region with plants and grass may automatically adjust the respective dimming level of the corresponding sub-areas in order to avoid unnecessary bright light for plants, grass, which could even irritate animals.

[0049] The memory 7 may furthermore hold a default set of setting values. In case that the automated determination of objects and / or regions, or the subsequent determination of setting values, forwhich a plausibility check may be performed, fails, the default set of setting values allows to load reasonable setting values for operation of the controllable light source 3.

[0050] The luminaire 2 may furthermore comprise an interface 8 allowing connecting the processing unit 6 with a terminal device 9, a server 10 or both. Using such a terminal device 9 enables an operator of the lighting system to adjust the representation initially generated by the camera 5. In order to enable the operator to adjust the representation, the processing unit 6 provides the representation received from the camera 5. The representation, in the simplest form an image captured by the camera 5, can be visualized using a display of the terminal unit 9. In addition or alternatively, the result of the analysis performed by the processing unit 6 on the representation provided by the camera 5, can be supplied via the interface 8 to the terminal device 9. In case that the representation analysis result is provided by the processing unit 6, the operator may directly correct determination results, identify an overall area of interest, or determine objects in the analysis result is being permanent. For example, buildings identified in the representation maybe fixed by the operator so that for future captured images, no repetitive analysis of these regions in the representation shall be performed by the processing unit 6. This reduces the computational cost for the analysis of new representations.

[0051] The visualization described with reference to the terminal device 9 may also be performed using the server 10 being connected to an input / output interface for the operator. In addition, the connection with the server 10 allows further analysis of data collected from the operation of the inventive lighting system 1. For example, images captured by the camera 5 as representations or analysis results derived from these representations can be stored in the server 10.

[0052] Advantageously, these representations or analysis results are stored in association with the respectively determined setting values for monitoring the operation of the controllable light source 3. In case that such information is repetitively collected and stored in the server 10, a change of information or lighting adjustment over time can be identified. Based on an analysis of such changes, counter measures can be initiated.

[0053] Figure 2 shows the major method steps for controlling the controllable light source 3 based on a representation of the environment covering an overall illumination area OIA as explained above. First, in step Si, environment sensing means sense the environment. According to the preferred embodiment, the sensing is performed by the camera 5 capturing an image of the environment of the luminaire 2 including the overall illumination area of the luminaire 2. By capturing an image of the environment, the camera 5 generates a representation of the environment in step S2. This representation includes the overall illumination area OIA and is forwarded to the processing unit 6. Alternatively, only the relevant portion of the representation (corresponding to the overall illumination are OIA) is supplied to the processing unit 6.Upon reception of the representation provided by the camera 5, the processing unit 6 analyses the received representation in step S3. Performing the analysis directly based on the representation as generated by the camera 5 in step S2 as indicated in step S3 of the diagram is one possible implementation of the inventive method. In such a case, the execution of the analysis of the representation may be performed directly in the luminaire 2 in case that the processing unit 6 is comprised by the luminaire 2.

[0054] Further, the preferred embodiment illustrated in figure 1 comprises the camera 5 within the luminaire 2. However, for performing the method steps as explained with reference to figure 2, it is also possible that the camera 5 is arranged external to the luminaire 2 and supplies image information on the captured image, or the generated representation of the environment, respectively, to the processing unit 6, which still may be arranged in the luminaire 2. The external camera 5 may be connected using a wired or a wireless connection. So the method steps presented in figure 2 do not necessarily need to be executed exclusively within the luminaire, which is the preferred embodiment of the present invention and shown in figure 1. However, the method according to the invention may also be performed by a distributed system. In particular, some of the method steps may even be executed by cloud services.

[0055] In the analysis of the representation according to step S3, objects and / or regions are determined in the representation. Based on the determined objects and / or regions in the representation, the processing unit 6 then identifies the sub-areas SA corresponding to the objects and / or regions identified in the representation. A setting value associated with the object type of the identified object is then determined for each sub-area SA corresponding to the determined object. Setting values are determined to define the light emission for sub-areas SA illuminating the determined object. Similarly, setting values associated with region types are determined for each sub-area SA corresponding to certain identified region in the representation. The determination of the setting values based on the result of the analysis of the representation in step S3 is performed in step S4.

[0056] The determined set of setting values is then provided to the control unit 4, which, based on the received setting values, controls the controllable light source 3. Controlling the light source 3 is performed in step S5.

[0057] As explained above with reference to the block diagram showing the inventive lighting system 1, it is not only possible to directly base the method steps on the representation of the environment is provided by the camera 5. It is also possible that, using the interface 8 of the luminaire 2, an operator of the system, for example a technician, is involved in setting conditions for the final determination of the setting values.For example, according to a preferred embodiment, the operator may use a terminal device 9 in order to input information, which is then taken into consideration when determining objects and / or determining setting values. In the flow chart illustrating the method steps, it is, for example, indicated that the representation generated in step S2 is visualized so that an operator can take measures considered to be necessary or advantageous based on the visualized representation. The representation is visualized in step S7, for example by outputting the image captured by the camera 5 on the terminal device 9. The terminal device 9 may be, for example, a mobile phone or a tablet computer.

[0058] The terminal device 9 may also serve as an input device so that the operator, in response to analyzing the visualized representation by himself, can input information that is then considered in the further process of determining the setting values. For example, in method step S8, the representation provided and visualized may be revised by the operator. Based on an input received by the terminal device 9 from the operator, adjustments may be performed in the representation before the revised representation is sent back in step S8. The further process as explained above, such as performing an analysis of the representation in step S3 and following method steps, is then performed based on the revised representation received from the terminal device 9.

[0059] Further, according to preferred embodiment, the analysis result of the representation including information on determined objects and / or regions may also be revised by the operator. This is achieved by providing the outcome of the analysis of the representation in step S3 to the terminal device 9. The analysis result may be presented to the operator either by visualizing the result, for example as an augmented image, in which the determined objects and / or regions are highlighted, for example using frames for highlighting identified objects and regions. This information may be enhanced by adding confidence values and the identified object / region type so that the operator may decide to confirm or dismiss a identification made. However, confirming and dismissing determination results is known in the art and is respectively applied for the present invention. The operator may input his information into the terminal device 9 in step S10. The result of the analysis performed in step S3 and provided in step S9 is revised based on the operator input. The revised result is then provided in step S11 and is thereafter used to determine setting values in step S4.

[0060] It is to be noted that the explanations strictly distinguish between method steps directly executed by the processing unit 6 and revision of the representation or analysis results performed by the operator. However, these aspects may also be combined. This means that, for example, the representation is directly analyzed by the processing unit 6 and, in addition, visualized in step S7. The revised representation, which is provided in step S8, is then taken intoconsideration in addition to the analysis directly performed on the representation as received from the camera 5. The results of both approaches may be merged.

[0061] Similar considerations apply to the analysis of the representation. For example, the operator may limit himself to identifying objects or determining areas of interest, negligible areas and so on, but ignore determinations on objects and or regions already made by the system. Again, the results provided by the system itself, namely the processing unit 6, and received after revising the result by the operator can be merged for determining the setting values in step S4.

[0062] The explanations provided above have been made with reference to a single luminaire 2.

[0063] However, the overall lighting system 1 may comprise a plurality of such luminaires or at least a plurality of environment sensing means and / or a plurality of controllable light sources 3. Such a plurality of controllable light sources 3 and, similarly, a plurality of cameras 5 may even share common processing capabilities. A plurality of such units may then be combined and communicate with each other to share information in a network.

[0064] Objects and / or regions which are of specific importance for being identified in a representation in order to accordingly control a controllable light source 3 are: driving lanes, pavements, green strips, trees and bushes, intersection and zebra crossing and house facades. This list only serves providing examples and is by no means exhaustive. As it is apparent from the aforementioned list or specific objects and regions, increasing illumination for critical areas such as zebra crossings and intersections may as well be considered as areas where illumination should be avoided. Such areas maybe for example house facades trees and bushes and green strips. For determining regions within the overall illumination area, pattern recognition may be performed on the representation of the environment including the overall illumination area. Based on such pattern recognition regions cobblestones, parking lots or the like may be determined.

[0065] While the above provided explanations clearly focus on ensuring a desired light intensity, it may also be considered that generating certain light patterns may enhance visibility of objects and / or regions. This may even include using different colors.

[0066] Although the major effect of the present invention is already achieved by detecting static areas once when the system is put into operation, it might be especially advantageous to reconfigure the system by repeating the generation of a representation and following steps including the determination of setting values from time to time, and to operate the lighting source using the latest set of determined setting values. As indicated by method step S 12 in the flowchart, it is preferred to increase brightness during capturing a new image by the camera 5. Alternatively orin addition, an auxiliary light source may be turned on illuminating the scenery with infrared light.

[0067] The repetition maybe performed after certain time intervals. One set of setting values maybe stored as a reference set of values, which can be used as a fallback (default) setting. Further, the representation and / or the result of the analysis of such reference representation performed on the initial representation generated when the system was put into operation, can be stored as a reference representation. In case that this representation, however, was generated on critical lighting conditions, for example because of bad weather, the reference representation (or analysis result thereof) may be overwritten with a new representation (or analysis result, respectively) being generated under better conditions. On the other hand, in case that only an initial representation is generated in order to determine a fixed set of setting values reflecting static objects and regions in the overall illumination area, it may be considered to use environment sensing means, for example camera 5, which are not permanently connected to the system. In such a case, a wireless connection between the camera and the processing unit 6 may be considered. The camera must then be connected only in case that a new representation shall be generated.

[0068] In case that a repetition of the generation of the representation shall be performed, the system may automatically search for reasonable conditions. This may include choosing a time of day when good lighting conditions can be expected, for example during daytime. On the other hand, it is also possible that other conditions may be taken into account. For example, temporary presence of people within the area of interest can be determined in the representation of the environment by analyzing the representation in the overall illumination area OIA with respect to people being present in the representation. If presence of people or other objects disturbing a proper analysis of the representation is recognizes, and it may be expected that disturbance is less at other times, capturing a new image in generating a new representation is postponed to a later point in time. At this point time it is then checked whether the number of disturbing people (objects) is below a threshold. If it is below, the new representation is generated, otherwise, the generation of a new representation maybe further postponed.

[0069] In the step of determining the setting values, it is also possible to take into consideration additional characteristics of the surfaces, which will be illuminated based on the determined setting values. For example, reflectivity of a surface of an object may be taken into consideration and the light intensity maybe adjusted in order to achieve a more homogeneous appearance of the illuminated object(s). In the same way, it can be considered whether a pavement is for example dark or bright. The different appearances of the determined objects for which setting values for the corresponding sub-areas SA are determined maybe compensated by adjusting thelight intensity accordingly. Characteristics like reflectivity do not necessarily need to be evenly present on the entire determined object and an adaptation of the setting values of the corresponding sub-areas of the determined object may be made for a part of the sub-areas SA according to the distribution of the characteristic on the object.

[0070] In case that reconfiguration of the system shall be achieved by preparing new representations and executing the following method steps including the determination of a new set of setting values, it might be helpful to switch on an auxiliary light, which specifically could be an infrared light source. It is also possible to use greyscale images in case that image capturing by the camera 5 must be performed in critical lighting conditions.

Claims

Claims:

1. Lighting system comprising- a controllable light source (3) for selectively adjusting at least one lighting parameter independently for a plurality of sub-areas SA, the plurality of sub-areas SA commonly constituting an overall illumination area OIA,- environment sensing means (5) for generating a representation at least of the overall illumination area OIA,- processing unit (6) configured to analyze the representation for determining objects (15) and / or regions in the representation and to determine a setting value for the at least one lighting parameter for each of the plurality of sub-areas SA depending on the determined objects (15) and / or regions- a control unit (4) configured to control light emission of the controllable light source (3) according to the determined values.

2. Lighting system according to claim 1, wherein the processing unit (6) is further configured to determine corresponding sub-areas SA by mapping one or more sub-areas SA on locations of objects (15) and / or regions in the representation.

3. Lighting system according to claim 1 or 2, wherein the lighting system further comprises a memory (7) storing a reference set of setting values for the at least one lighting parameter for the overall illumination area OIA.

4. Lighting system according to any of the preceding claims, wherein the system comprises a memory storing a reference representation and / or an analysis result of such reference representation.

5. Lighting system according to any of the preceding claims, wherein the lighting system comprises a memory (7) storing setting value information associated with objects (15) and or regions identifiable in the representation.

6. Lighting system according to any of the preceding claims, wherein the processing unit (6) is configured to adapt the setting values for the at least one lighting parameter for a corresponding sub-area in response to a confidence value for recognition of the object (15) and / or area corresponding to this corresponding sub-area.

7. Lighting system according to any of the preceding claims, wherein the lighting system comprises an auxiliary light source for illuminating the overall illumination area with infrared light.

8. Lighting system according to any of the preceding claims, wherein the processing unit is connectable to a terminal device (9) and / or a server (10) for outputting a result of the analysis of the representation.

9. Lighting system according to any of the preceding claims, wherein the processing unit (6) is connectable to a terminal device (9) and / or a server (10) for adjusting a result of the analysis of the representation.

10. Method for individually controlling illumination of a plurality of sub-areas SA commonly constituting an overall illumination area OIA of a controllable light source (3), the method comprising the steps of:- sensing an environment (Si) at least corresponding to the overall illumination area and generating a representation (S2) thereof,- analyzing the representation (S3) for determining objects (15) and / or regions in the representation,- determining a setting value (S4) for the at least one lighting parameter for each of the plurality of sub-areas depending on the determined object (15) and / or regions, and- controlling light emission (S5) of the controllable light source (3) according to the determined values for each of the plurality of sub-areas SA.

11. Method according to claim 10, wherein the steps of: sensing the environment, analyzing the representation, determining setting values are repetitively executed according to a predefined time schedule, or upon reception of a trigger signal, or in response to determination of changes in the representation and / or of the analysis result of the representation less than a first predefined amount, or in response to determination of changes in the representation and / or of the analysis result of the representation exceeding a second predefined amount case the determined change means for a predefined time interval.

12. Method according to claim 11, a default set of setting values is loaded in case that determination of objects and / more regions in the representation is ambiguous.13- Method according to any one of claims 10 to 12, wherein the setting values may at least be partially adapted in response to predefined characteristics of determined objects (15) and / or regions.

14. Method according to any one of claims 10 to 13, wherein the processing unit (6) adapts the setting values (S4) for the at least one lighting parameter for a corresponding area in response to a confidence value for recognition of the object and / or area corresponding to this corresponding area.

15. Method according to any one of claims 10 to 14, wherein the processing unit (6) adjusts the setting values (4) to increase brightness (S12) at least in the illuminated sub-areas SA during sensing the environment (Si) for generating the representation.

16. Method according to any one of claims 10 to 15, wherein at least one of the representation and the result of the analysis of the representation is visualized (S7, S9) and presented to an operator of the lighting system.

17. Method according to claim 16, wherein at least one of a revision of the representation (S8) and an adjustment of the result of the analysis of the representation (S 10) performed by the operator of the lighting system is read in and determination of setting values for the at least one lighting parameter (S4) is performed based on an analysis of the revised representation (S3) and the adjusted result of the analysis, respectively.

18. Method according to any one of claims 10 to 17, wherein at least one of the result of the analysis of the representation and the correspondingly determined setting values of the at least one lighting parameter is output for monitoring.

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