Abstract:
Disclosed herein are an adaptive illumination apparatus and an adaptive illumination method. The adaptive illumination apparatus is associated with a target scene and comprises a control module and an illumination module. The control module is configured to generate a command associated with an area included in the target scene. 
     Specifically, the control module selects the area and determines a scope and a direction associated therewith based on a brightness distribution of the target scene, receives a distance parameter associated with a distance between the area and the illumination module, and indicates said scope, direction and distance parameter in the command. The illumination module, coupled with the control module, is capable of panning, tilting, and zooming. Based on the command, the illumination module performs panning, tilting, or zooming and illuminates the area.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 103126089 filed in Taiwan, R.O.C. on Jul. 30, 2014, the entire contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The disclosure relates to sense illumination, more particularly to an adaptive illumination apparatus with pan, tilt and zoom (abbreviated to PTZ) functions and an adaptive illumination method. 
       BACKGROUND 
       [0003]    Video, static-image or surveillance cameras usually have a flash or a light compensation device. Projecting strong light onto a dark scene to be shot is the easiest way to compensate light. By doing so, though the scene becomes brighter, overexposure easily occurs to a portion of the capturing result, which corresponds to an object close to the lens or the light source in the scene. For the light compensation based on infrared (IR) light, a smart IR light technology has been promoted to solve such a problem. However, this technology is carried out by the decrease of intensity of output light so may darken a certain portion of the capturing result, which has a proper exposure. 
       SUMMARY 
       [0004]    According to one or more embodiments, the disclosure provides an adaptive illumination apparatus associated with a target scene. In one embodiment, the adaptive illumination apparatus includes a control module and an illumination module. The illumination module is coupled to the control module. The control module generates a command. The illumination module, according to the command, pans, tilts or zooms for illuminating an area associated with the command. The area is in the target scene. When generating the command, the control module selects the area according to a brightness distribution of the target scene and defines a scope and direction associated with the area. The control module also receives a distance parameter associated with a distance between the area and the illumination module and indicates the scope, direction or distance parameter in the command. 
         [0005]    According to one or more embodiments, the disclosure provides an adaptive illumination method associated with a target scene. In one embodiment, the adaptive illumination method includes the following steps. A command is generated to control an illumination module to pan, tilt or zoom for illuminating an area in the target scene. 
         [0006]    When the command is generated, the area is selected according to a brightness distribution of the target scene and a relative scope and direction associated with the area are defined according to the brightness distribution of the target scene. A distance parameter that is associated with a distance between the area and the illumination module is received. In the command, the scope, direction or distance parameter is indicated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not limitative of the present invention and wherein: 
           [0008]      FIG. 1  is a block diagram of an adaptive illumination apparatus according to an embodiment of the disclosure; 
           [0009]      FIG. 2  is a schematic diagram of the operation of the illumination module according to an individual command according to an embodiment of the disclosure; and 
           [0010]      FIG. 3  is a flow chart of an adaptive illumination method according to an embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings. 
         [0012]    Please refer to  FIG. 1 , which is a block diagram of an adaptive illumination apparatus  1  according to an embodiment of the disclosure. The adaptive illumination apparatus  1  includes a control module  10 , a first illumination module  11 , an optional capturing module  13 , and an optional distance parameter capturing module  15 . The control module  10  is, for example but not limited to, a microcontroller, microprocessor, application-specific integrated circuit, field-programmable gate array, complex programmable logic device, system-on-chip or system-in-package. The illumination module  11  emits light that is, for example but not limited to, infrared light or visible light. The operation of the adaptive illumination apparatus  1  is exemplarily illustrated below. 
         [0013]    The control module  10  is coupled with the illumination module  11 . The control module  10  generates a first command. The illumination module  11 , according to the first command, illuminates a target scene associated with the adaptive illumination apparatus  1 . 
         [0014]    As shown in  FIG. 2 , the operation of the illumination module  11  is illustrated. The target scene indicates a three-dimensional space (p, t, z) which the adaptive illumination apparatus  1  faces to and a certain external camera or a capturing module  13  can capture images for. The three-dimensional space (p, t, z) can be a Cartesian coordinate system or other possible coordinate systems. For the illumination of the illumination module  11 , most of the time the target scene is considered as an imaginary projection plane  2  parallel to the p-t plane. The projection plane  2  is at any location along the z axis. The projection plane  2  associated with the first command includes a first area  21  that is a projection image of a single object  41  or a group of objects  41 . In other words, the control module  10  generates the first command for controlling the illumination module  11  to illuminate the object  41 , and the control module  10  may make sense of the area  21  rather than the object  41 . 
         [0015]    Please refer to  FIG. 3 , which is a flow chart of an adaptive illumination method according to an embodiment of the disclosure. Generating the above first command by the control module  10  includes steps S 31  to S 36 . In step S 31 , the control module  10  selects the area  21  according to a brightness distribution of the target scene. The brightness distribution of the target scene is presented by, for example but not limited to, luma values, an image histogram or a color histogram, which is generated by recording brightness of each point or area of the projection plane  2 . In an embodiment, the brightness distribution of the target scene can be obtained by acquiring data from an external device such as a luminance meter or a photometer, which records brightness of each point or area of the projection plane  2 . In another embodiment, the brightness distribution of the target scene can be obtained by acquiring data from the capturing module  13  that is coupled to the control module  10 , functions as a camera to capture images of the target scene, and outputs a digitalized capturing result. The brightness distribution of the target scene is obtained from the capturing result of the capturing module  13  or the control module  10 . The adaptive illumination apparatus  1  including the capturing module  13  integrates the illumination function with at least a basic capturing function. 
         [0016]    Generally, an area relatively darker than other areas in the projection plane  2  in view of the brightness distribution of the projection plane  2  would make neither the capturing module  13  nor the external camera used by the adaptive illumination apparatus  1  be able to capture great images for the target scene. Therefore, the control module  10  selects such an area as the area  21 . In an embodiment, the area  21  is a portion of the projection plane  2 , which has a brightness average that is less than a certain threshold. The disclosure has no limitation on how to define or distinguish every portion of the projection plane  2  or how to average values of the brightness distribution. 
         [0017]    In step S 31 , the control module  10  further defines a scope  213  and a direction  211  associated with the area  21 . Since the area  21  corresponds to the object  41  in the target scene, the control module  10  commands the illumination module  11  to illuminate in accordance with the shape of the area  21  or the object  41  or in accordance with a portion of the object  41 , such as a scope  213  as shown in  FIG. 2 . In an embodiment, the scope  213  is sufficiently equal to or smaller than an incircle of the contour of the object  41 , but the disclosure will not limited thereto. In an embodiment, the direction  211  is a direction from the illumination module  11  to any point on the area  21 , and the reference point  410  associated with the object  41  is on the direction  211 . In an embodiment, the direction  211  is a direction from the illumination module  11  to the centroid of the area  21  or a point close to the centroid of the area  21 . 
         [0018]    In step S 33 , the control module  10  receives a first distance parameter d 1  associated with a distance between any point on the first area  21  (i.e. the object  41 ) and the illumination module  11 . For example, the distance parameter is a length obtained by the laser ranging or is a depth of field in the image processing industry. In an embodiment, the distance parameter is obtained from an external device. In another embodiment, the distance parameter is obtained directly from a distance parameter capturing module  15 . The distance parameter capturing module  15  is coupled with the control module  10 . In an embodiment, the distance parameter capturing module  15  can detect the distance or the depth of filed and includes at least one or more capturing units. The one or more capturing units can record a depth map corresponding to the projection plane  2  in response to the target scene. 
         [0019]    In this embodiment, step S 33  follows step S 31 , the control module  10  receives the distance parameter d 1 , and the depth map of the entire target scene may be used. In an embodiment, the capturing module  13  can function as the above capturing unit, and the subsumption and connection relationships between the capturing module  13  and the distance parameter capturing module  15  are not shown in  FIG. 1 . In this case, the capturing module  13  may directly be coupled with the control module  10 . The disclosure has no limitation on the techniques for carrying out the distance parameter capturing module  15 . As shown in  FIG. 2 , the distance parameter d 1  is on an extension line starting passing through the reference point  410  at the direction  211 . In an embodiment, the distance parameter capturing module  15  obtains multiple second distance parameters associated with distances between multiple points on the illumination module  11  and multiple points on the object  41  (i.e. the area  21  that is a portion of the target scene) and then averages them to obtain the first distance parameter d 1 . In this or some embodiments, the reference point  410  may be on the object  41 . The disclosure has no limitation on how to average the second distance parameters and which points on the object  41 . 
         [0020]    Light projected by the illumination module  11  is efficient and useful in a certain maximum distance. In an embodiment, a maximum distance parameter associated with the maximum distance is stored in the control module  10  in advance. Therefore, when the object  41  is too far from the illumination module  11 , the distance parameter d 1  will larger than the maximum distance parameter and then the control module  10  will not generate the first command or will replace the distance parameter d 1  by the maximum distance parameter. In another embodiment, the illumination module  11  directly sets the distance parameter d 1  exceeding the maximum distance parameter to be a new maximum distance parameter. 
         [0021]    In step S 35 , the control module  10  subsumes (indicates) a scope  213 , the direction  211  or the distance parameter d 1  in the first command. In step S 36 , the control module  10  sends the first command to the illumination module  11 . In step S 38 , the illumination module  11  pans in relation to the p axis, tilts in relation to the t axis, or zooms in relation to the z axis to generate a light distribution (also known as light pattern)  118  according to the first command. In step S 39 , the illumination module  11  illuminates the area  21  or the object  41 . 
         [0022]    The above direction  211  is associated with the panning and tilting of the illumination module  11 , and the above scope  213  and the above distance parameter d 1  are associated with the zooming of the illumination module  11 . Since the illumination module  11  includes movable components respectively acting at p, t and z dimensions. The movable component acting at the z dimension can adjust the orientation of the lens (or lens assembly), lampcup or light source of the illumination module  11 . In an embodiment, even if the distance parameter is unchanged, the illumination module  11  can still emit light with a light distribution with a different scope by the moving of the movable component at the z dimension. Therefore, the first command will indicate the scope  213  and the distance parameter d 1  simultaneously. In another embodiment, the size of the scope is negatively correlative to the distance parameter. In other words, while the light distribution is convergent more, the projected light travels more far. Therefore, the first command will indicate either the scope  213  or the distance parameter d 1 . The light distribution  118  in  FIG. 2  has a cone, but the disclosure will not be limited thereto. 
         [0023]    In an embodiment, the adaptive illumination apparatus  1  further includes a second illumination module  12  or more illumination modules. In an embodiment, the panable, tiltable and zoomable illumination module  11  can illuminate against a specific area while the illumination module  12  is selectively controlled by the control module  10  to non-directionally and widely illuminate the entire target scene or a certain second area of the target scene. The scope and the distance parameter may negatively be correlative so such wide-illumination can be applied to the object close to the external camera or the capturing module  13 . In an embodiment, the illumination module  12  is similar to the illumination module  11  in function and illuminates a second area which is relatively darker, in response to a second command generated by the control module  10 . The relative operation of the illumination module  12  can refer to  FIG. 3 . The first and second areas overlap each other in an embodiment or are the same one in another embodiment but the scope indicated by the first command may be different from the scope indicated by the second command. 
         [0024]    For example, as shown in  FIG. 2 , if the scope  213  cannot cover the object  41 , the control module  10  will command the illumination module  12  to deal with the uncovered portion of the object  41 . Herein, if the illumination module  11  can not deal with it, the area  21  will still be relatively darker. Therefore, the control module  10  further commands the illumination module  12  to illuminate the object  41  at the direction  221  a. 
         [0025]    In an embodiment, the first and second areas respectively correspond to different objects or different groups of objects in the target scene. As shown in  FIG. 2 , the illumination module  12 , according to the light distribution  128 , illuminates an object  42  that corresponds to the second area  22  and is separated from the object  41 , to fit the second command that indicates the direction  221 , the scope  223  and the distance parameter d 2 . The direction  221  is from the illumination module  12  to the reference point  420  associated with the object  42 . The distance d 2  is shorter than the distance d 1 . The scope  223  is sufficiently equal to or slightly larger than a circumcircle of the contour of the object  42 . This is one of the schemes for the control module  10  to a closer object, e.g. the object  42 . In an embodiment, the control module  10  usually controls the illumination module  11  to illuminate in a far distance and controls the illumination module  12  to illuminate in a near distance. In an alternative embodiment, the control module  10  usually controls the illumination module  12  to illuminate in a far distance and controls the illumination module  11  to illuminate in a near distance. The differences between the first and second commands may relate to the differences in function or performance between the illumination modules  11  and  12  in an embodiment. 
         [0026]    In an embodiment, the adaptive illumination method is performed with an automatic exposure (AE) algorithm. For example, the illumination module  11  or  12  is illuminating until this algorithm can perform the post-process to captured images. Alternately, during the pretreatment process, this algorithm may deal with no existence of any useful or meaningful distance parameter or brightness distribution caused by the overexposure or underexposure output of the capturing unit or capturing module when light compensation is not adaptive or has not been performed yet. That is, the AE algorithm adjusts the output of the capturing unit or capturing module. Then, a useful or meaningful distance parameter or brightness distribution can be obtained. 
         [0027]    In view of the foregoing embodiments, the disclosure employs an illumination module with PTZ functions to adaptively illuminate a target scene. Adaptive illumination is based on a brightness distribution of the target scene and a distance parameter associated with the brightness distribution of the target scene. Illuminating the target scene is based on the functions of the above components in the adaptive illumination apparatus.