Abstract:
An imaging apparatus includes: an image creating section imaging a predetermined surveillance range and creating image data; an image processing section in which computing processing means having a predetermined processing ability performs first image processing of detecting an abnormality in the surveillance range in accordance with the image data and generating a first detection signal and second image processing of converting the image data to a predetermined data format in parallel; and a determination processing section determining whether a predetermined subject under surveillance exists in the surveillance range or not based on the first detection signal, generating and supplying a first control signal to the image processing section if it is determined that the subject under surveillance does not exist, and generating and supplying a second control signal to the image processing section if it is determined that the subject under surveillance exists.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present invention contains subject matter related to Japanese Patent Application JP2006-034287 filed in the Japanese Patent Office on Feb. 10, 2006, the entire contents of which being incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an imaging apparatus that images a predetermined surveillance range and detects a subject under surveillance and a control method therefor. 
     2. Description of the Related Art 
     A surveillance camera is provided in various places for monitoring a suspicious person, for example, in a surveillance range. Some surveillance cameras may detect whether a subject under surveillance exists in a surveillance range or not based on an imaged image. JP-A-2004-128899 (Patent Document 1) discloses a technology in which multiple surveillance cameras image a surveillance range from different image angles and supply the imaged images to a host computer, and the host computer detects an abnormality in the surveillance range based on the data and performs a surveillance activity by connecting the surveillance cameras in accordance with the detection result. 
     Furthermore, a surveillance camera in the past may perform various kinds of image processing such as processing of detecting a subject under surveillance based on an imaged image, transmission processing of transmitting an imaged image to external equipment, processing of compressing an imaged image and processing of recording an imaged image. The surveillance camera allocates the processing ability of a computing processing unit within the camera to each image processing in advance and performs multiple kinds of image processing in parallel by using the computing processing unit. 
     SUMMARY OF THE INVENTION 
     However, a surveillance camera in the past that performs the various kinds of image processing may not efficiently use the processing ability of a computing processing unit provided within the camera since one kind of image processing is allocated an unnecessarily larger proportion of the processing ability in accordance with the state of a surveillance range while the other image processing is not allocated sufficient processing ability. 
     Accordingly, it is desirable to propose an imaging apparatus that can efficiently use the processing ability of a computing processing unit that performs image processing and a control method for the imaging apparatus. 
     According to an embodiment of the present invention, there is provided an imaging apparatus including an image creating section imaging a predetermined surveillance range and creating image data, an image processing section in which computing processing means having a predetermined processing ability performs first image processing of detecting an abnormality in the surveillance range in accordance with the image data and generating a first detection signal and second image processing of converting the image data to a predetermined data format in parallel, and a determination processing section determining whether a predetermined subject under surveillance exists in the surveillance range or not based on the first detection signal, generating and supplying a first control signal to the image processing section if it is determined that the subject under surveillance does not exist, and generating and supplying a second control signal to the image processing section if it is determined that the subject under surveillance exist, wherein the image processing section allocates a larger proportion of the processing ability of the computing processing means to the first image processing than that to the second image processing if the first control signal is supplied thereto and allocates a larger proportion of the processing ability of the computing processing means to the second image processing than that to the first image processing if the second control signal is supplied thereto. 
     According to another embodiment of the invention, there is provided a control method for an imaging apparatus that images a predetermined surveillance range and detects a subject under surveillance, the method including the steps of imaging the surveillance range and creating image data, performing first image processing of detecting an abnormality in the surveillance range in accordance with the image data and generating a first detection signal and second image processing of converting the image data to a predetermined data format in parallel by computing processing means having a predetermined processing ability, determining whether the subject under surveillance exists in the surveillance range or not based on the first detection signal, allocating a larger proportion of the processing ability of the computing processing means to the first image processing than that to the second image processing if it is determined that the subject under surveillance does not exist in the surveillance range, and allocating a larger proportion of the processing ability of the computing processing means to the second image processing than that to the first image processing if it is determined that the subject under surveillance exists in the surveillance range. 
     According to the embodiments of the invention, whether the subject under surveillance exists in a surveillance range or not is determined based on a first detection signal. A larger proportion of the processing ability of computing processing means is allocated to first image processing than that to the second image processing if it is determined that the subject under surveillance does not exist in the surveillance range, and a larger proportion of the processing ability of computing processing means is allocated to second image processing than that to the first image processing if it is determined that the subject under surveillance exists in the surveillance range. 
     Thus, according to the embodiments of the invention, since a large proportion of the processing ability of computing processing means is allocated to necessary image processing in accordance with the state of a surveillance range, the image processing ability of the imaging apparatus can be increased without increasing the processing ability of the computing processing means. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram showing a construction of a surveillance system; 
         FIG. 2  is a block diagram showing a construction of a surveillance camera; 
         FIGS. 3A and 3B  are schematic diagrams showing the allocation of the processing ability of a processor in accordance with a detection mode ( 3 A) and a shooting mode ( 3 B); 
         FIG. 4  is a flowchart showing processing steps by an image processing section in accordance with the detection mode and the shooting mode; and 
         FIGS. 5A and 5B  are schematic diagrams showing the allocation of the processing ability of a processor in accordance with the detection mode ( 5 A) and the shooting mode ( 5 B). 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to drawings, a specific embodiment according to the invention will be described in detail below. 
     As shown in  FIG. 1 , a surveillance system  1  includes a surveillance camera  10 , an external recording device  20 , a door open/close sensor  30  and a window open/close sensor  40 . The surveillance camera  10  images a predetermined surveillance range. The external recording device  20  records an image imaged by the surveillance camera  10 . The door open/close sensor  30  detects the opening or closing of a door and outputs a detection signal. The window open/close sensor  40  detects the opening or closing of a window and outputs a detection signal. 
     The surveillance camera  10  images a surveillance range and transmits image data obtained from an imaged image to the external recording device  20  via a predetermined communication cable  2 . The surveillance camera  10  further supplies a sensor signal from the door open/close sensor  30  and window open/close sensor  40  through predetermined sensor signal lines  3   a  and  3   b.    
     The external recording device  20  receives and records image data transmitted from the surveillance camera  10  via the communication cable  2 . 
     The door open/close sensor  30  is a sensor that detects the opening or closing of a door and determines that an abnormality occurs in a surveillance range if a door is opened and supplies the sensor signal to the surveillance camera  10  through the sensor signal line  3   a.    
     The window open/close sensor  40  is a sensor that detects the opening or closing of a window and determines that an abnormality occurs in a surveillance range if a window is opened and supplies the sensor signal to the surveillance camera through the sensor signal line  3   b.    
     Next, referring to  FIG. 2 , a construction of the surveillance camera  10  will be described in detail. 
     The surveillance camera  10  includes an optical lens  11 , an image creating section  12 , an image processing section  13 , a determination processing section  14 , an image data communicating section  15 , an image recording section  16 , a sensor signal input section  17  and a setting information communicating section  18 . 
     The image creating section  12  creates image data from a subject in a surveillance range captured by the lens  11  and supplies the image data to the image processing section  13 . More specifically, the image creating section  12  creates image data by performing processing such as contrast adjustment, gamma correction, edge correction and frame interpolation on an imaged image. 
     The image processing section  13  includes a compression processing section  13   a , a distribution processing section  13   b , a recording processing section  13   c  and a detection processing section  13   d . The image processing section  13  performs processing of the processing sections by a processor having a predetermined processing ability. The image processing section  13  may perform processing of the processing sections by using multiple interlocking processors without limiting to the case that processing of the processing sections is performed by one processor. The image processing section  13  allocates the predetermined processing ability of the processor to the processing sections  13   a  to  13   d  and performs those kinds of processing in parallel on the processor. 
     The compression processing section  13   a  compresses image data supplied from the image creating section  12  and creates compressed image data. The compression processing section  13   a  supplies the compressed image data to the distribution processing section  13   b  and recording processing section  13   c.    
     The distribution processing section  13   b  converts the compressed image data supplied from the compression processing section  13   a  to a communication format compatible with the image data communicating section  15  and supplies the result to the image data communicating section  15 . 
     The recording processing section  13   c  converts the compressed image data supplied from the compression processing section  13   a  to a recording format compatible with the image recording section  16  and supplies the result to the image recording section  16 . 
     The detection processing section  13   d  detects whether an abnormality occurs within a surveillance range or not from image data supplied from the image creating section  12  and supplies the image processing detection signal in accordance with the detection result to the determination processing section  14 . Here, the abnormality refers to a change in state within a surveillance range and is detected by processing steps which will be specifically described below. That is, the detection processing section  13   d  compares multiple pieces of image data at serial imaged times, extracts a part having a movement in a subject and detects whether an abnormality occurs within a surveillance range or not. Then, the detection processing section  13   d  supplies an image detection signal in accordance with the information on the size and/or moving time of the extracted moving part to the determination processing section. 
     The image data communicating section  15  transmits compressed image data in a predetermined communication format supplied from the distribution processing section  13   b  to the external recording device  20  via the communication cable  2 . 
     The image recording section  16  records compressed image data in a predetermined recording format supplied from the recording processing section  13   c  onto a predetermined recording medium. 
     The sensor signal input section  17  receives the input of and supplies the sensor signals supplied from the door open/close sensor  30  and window open/close sensor  40  to the determination processing section  14  through the sensor signal lines  3   a  and  3   b.    
     The setting information communicating section  18  detects a setting information signal supplied from a predetermined information processing apparatus through a predetermined communication unit and supplies the setting information in accordance with the setting information signal to the determination processing section  14 . Here, the setting information signal refers to a communication signal in accordance with a control command to the surveillance camera  10 , such as a start command and an imaging start command. 
     The determination processing section  14  determines whether a subject under surveillance exists in a surveillance range or not based on the image detection signal supplied from the detection processing section  13   d  and the sensor signal supplied from the sensor signal input section  17  and supplies a control signal in accordance with the determination result to the image processing section  13 . More specifically, the determination processing section  14  sets a threshold value to each of multiple determination factors based on an image detection signal and/or a sensor signal and determines whether a subject under surveillance exists or not based on whether these determination factors are higher than the threshold values. The determination processing section  14  determines these determination factors in accordance with the setting information supplied from the setting information communicating section  18 . 
     The image processing section  13  allocates the processing ability of the processor to the processing sections  13   a  to  13   d  in accordance with the control signal supplied from the determination processing section  14 . More specifically, the processing ability of the processor is allocated to the processing sections  13   a  to  13   d  based on the control signal and in accordance with a detection mode or a shooting mode as shown in  FIGS. 3A and 3B . In the detection mode, as shown in  FIG. 3A , a larger proportion of the processing ability of the processor is allocated to the detection processing section  13   d  than those to the compression processing section  13   a , distribution processing section  13   b  and recording processing section  13   c . On the other hand, in the shooting mode, as shown in  FIG. 3B , a larger proportion of the processing ability of the processor is allocated to the compression processing section  13   a , distribution processing section  13   b  and recording processing section  13   c  than that to the detection processing section  13   d.    
     The proportion to be allocated of the processing ability to the processing sections  13   a  to  13   d  in the image processing section  13  in accordance with the detection mode and shooting mode may be pre-set or may be set in accordance with the setting information supplied from the setting information communication section  18  to the determination processing section  14 . 
     Next, processing steps by the image processing section  13  in accordance with the detection mode and shooting mode will be described in detail with reference to  FIG. 4 . It is assumed that the processing steps are performed when a suspicious person who is a subject under surveillance brakes into a surveillance range. 
     In the initial stage of the processing steps, the image processing section  13  is first set at the detection mode to cause the detection processing section  13   d  to detect an abnormality in a surveillance range faster. 
     In step S 1 , the image processing section  13  causes the detection processing section  13   d  to detect whether an abnormality occurs within a surveillance range or not in accordance with the image data supplied from the image creating section  12 . The detection processing section  13   d  repeats the detection processing until an abnormality occurs within the surveillance range, supplies an image detection signal to the determination processing section  14  and moves to step S 2  when the fact that an abnormality occurs within the surveillance range is detected. The determination processing section  14  determines the fact that a suspicious person has broken into the surveillance range in accordance with the image detection signal supplied from the detection processing section  13   d  and the sensor signal supplied from the sensor signal input section and supplies the control signal to shift from the detection mode to the shooting mode to the image processing section  13  in accordance with the determination result. 
     In step S 2 , the image processing section  13  shifts the processor from the detection mode to the shooting mode in accordance with the control signal supplied from the determination processing section  14 . After the shift to the shooting mode, the image processing section  13  allocates a larger proportion of the processing ability of the processor to compression processing, for example than that to detection processing and performs processing of storing and distributing image data resulting from the imaging of a suspicious person mainly. The image processing section  13  allocates a part of the processing ability of the processor to the detection processing even after the shift to the shooting mode, and the detection processing is continuously performed. The detection processing by the image processing section  13  in the shooting mode will be described for the subsequent processing steps. 
     In step S 3 , the image processing section  13  causes the detection processing section  13   d  to detect a suspicious person in accordance with the image data supplied from the image creating section  12 . The detection processing section  13   d  repeats the detection processing until a suspicious person is no longer detected, supplies an image detection signal to the determination processing section  14  and moves to step S 4  when a suspicious person is no longer detected. On the other hand, the determination processing section  14  detects that a suspicious person no longer exists in the surveillance range in accordance with the image detection signal and sensor signal and supplies a control signal to shift from the detection mode to the shooting mode to the image processing section  13  in accordance with the determination result. 
     In step S 4 , the image processing section  13  shifts the processor from the shooting mode to the detection mode in accordance with the control signal supplied from the determination processing section  14 . 
     By following these processing steps, the image processing section  13  selects the detection mode or the shooting mode and performs image processing. Then, since the image processing section  13  performs the processing in step S 1  in the detection mode, the fact that a suspicious person has broken into a surveillance range can be detected faster than the operation in the shooting mode. 
     On the other hand, since the image processing section  13  performs the processing of detecting a suspicious person in the shooting mode in step S 3 , the fact that a suspicious person has left the surveillance range may not be detected faster than the operation in the detection mode. However, the reduction in speed of the detection of the fact that a suspicious person has left the surveillance range may not have an effect on missing the suspicious person in shooting and therefor a less effect on the surveillance activity. In other words, in step S 3 , the image processing section  13  can allocate larger proportions of processing ability to the compression processing section  13   a , distribution processing section  13   b  and recording processing section  13   c  than the processing ability to the detection processing section  13   d  that detects a suspicious person in the shooting mode. 
     Since the surveillance camera  10  can allocate the processing ability of the processor of the image processing section  13  properly to the processing sections  13   a  to  13   d  in accordance with the detection mode and shooting mode as described above, each of the image processing abilities can be improved without requiring an increase in processing ability of the processor itself. 
     The processing ability of the processor in a surveillance camera may be often limited when the power supply is limited, when the upper limit of the normal operational temperature of a surveillance camera is set higher in order to use the surveillance camera outdoors and/or when the budget is limited. Since each of the image processing abilities can be improved in the surveillance camera  10  according to this embodiment without any increase in processing ability of the processor itself, the image processing abilities can be achieved which may not have been achieved in the past when the processing ability of the processor is limited. 
     Notably, the processing ability of the processor of the image processing section  13  may be allocated to the processing to be performed by the image creating section  12 . In this case, the processing ability of the processor is allocated to the processing sections in accordance with the detection mode and shooting mode as described below. 
     More specifically, in the detection mode, a larger proportion of the processing ability of the processor is allocated to the processing of the detection processing section  13   d  than those to the image data adjustment processing to be performed by the compression processing section  13   a , distribution processing section  13   b , the recording processing section  13   c  and the image creating section  12 , as shown in  FIG. 5A . On the other hand, in the shooting mode, a larger proportion of the processing ability of the processor is allocated to the image data adjustment processing to be performed by the compression processing section  13   a , distribution processing section  13   b , the recording processing section  13   c  and the image creating section  12  than that to the processing of the detection processing section  13   d , as shown in  FIG. 5B . 
     The invention is not limited to the embodiment, but various changes may be made thereto without departing from the scope and spirit of the invention. 
     It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.