JP2008244958A - Imaging system and operation control method thereof - Google Patents

Abstract

[Objective] To reduce the amount of MPEG compressed image data.
[Structure] An imaging target area is imaged at a constant period, and an image for each frame is obtained at a constant period. When there is movement in the imaging target area at times t2 to t3, t4 to t5, t6 to t7, and t8 to t9, an I frame is generated at a constant period, and a P frame or a B frame is generated between the I frames. If there is no movement in the imaging target area at times t1 to t2, t3 to t4, t5 to t6, and t7 to t8, an I frame is not generated and a P frame or a B frame is generated. Since the number of I-frame generations with a relatively large amount of data after compression is reduced, the amount of data is reduced.
[Selection] Figure 1

Description

  The present invention relates to an imaging system and an operation control method thereof.

In the monitoring camera, the imaging target range that is the monitoring target is continuously imaged at a constant period. Image data obtained by imaging is compressed and recorded on a recording medium. Since the surveillance camera always images the imaging target range, the data amount of image data obtained by imaging increases. In order to prevent the amount of image data from increasing, there is a technique in which the frame rate is changed between a portion where an intruder is detected and a portion where an intruder is not detected (Patent Document 1).
JP 2002-262273 A

  However, the amount of image data is still large.

  An object of the present invention is to reduce the amount of image data.

  An imaging system according to the present invention continuously captures a predetermined imaging target range at a constant cycle, and sequentially outputs image data representing an image within the imaging target range for each frame. The image data of the first frame among the image data sequentially output for each frame from the image sensing means, the motion determining means for inputting the image data sequentially output for each frame and determining the presence or absence of motion within the imaging target range The image data representing the image is completely compressed so that it becomes a complete image of one frame, and the image data representing the image of the remaining frame is determined according to the motion determining means determining that there is motion The complete compression process is performed, and when the motion determination means determines that there is no motion, Characterized in that it comprises compression means for performing differential information compression processing to indicate minute information, and the recording control means for controlling the recording medium to record the image data compressed by said compression means.

  The present invention also provides an operation control method suitable for the imaging system. That is, in this method, the imaging unit continuously captures a predetermined imaging target range at a constant cycle, sequentially outputs image data representing the images in the imaging target range for each frame, and the motion determination unit However, the image data sequentially output from the imaging means for each frame is input, the presence or absence of motion within the imaging target range is determined, and the compression means outputs the image data sequentially output from the imaging means for each frame. Of these, the image data representing the first frame image is completely compressed so that it becomes a complete one-frame image, and the image data representing the remaining frame image is moved by the motion determination means. The complete compression process is performed according to the determination, and the front frame is detected according to the determination by the movement determination means that there is no movement. Performs differential information compression processing to indicate difference information between beam, the recording control means is for controlling the recording medium to record the image data compressed by said compression means.

  According to the present invention, the imaging target range is continuously imaged at a constant period, and image data representing images within the imaging target range is sequentially output for each frame. When there is movement within the imaging target range, complete compression processing is performed so that a complete one-frame image is obtained. When there is no movement within the imaging target range, a difference indicating difference information from the previous frame Compression processing is performed. Fully compressed image data or differentially compressed image data is recorded on a recording medium. According to the present invention, if there is no movement, differential compression processing is performed. Since the data amount of the image data subjected to differential compression processing is smaller than the data amount of image data subjected to complete compression processing, the data amount of data recorded on the recording medium is reduced. When there is movement, complete compression processing is performed, so that a relatively high-quality image can be obtained.

  FIG. 1 is a conceptual diagram of a moving image compressed according to an embodiment of the present invention. In this figure, the letter I is attached to the I frame, the letter P is attached to the P frame, and the letter B is attached to the B frame.

  In compression based on MPEG (Moving Picture Experts Group), compression and expansion are generally performed in units of GOP (Group of Picture) composed of I frame, P frame, and B frame. The I frame is a reference frame and is generated by spatial compression (complete compression processing). An I frame is a complete image of only one I frame. The P frame and the B frame are generated by time axis compression (differential compression processing). The P frame and the B frame indicate difference information from other frames.

  In general, an I frame is periodically inserted, and a P frame and a B frame are inserted between the I frames. In this embodiment, it is determined whether or not there is motion within the imaging target range. When it is determined that there is motion, I frames are periodically inserted. When it is determined that there is no motion, P frames or B frames are inserted without inserting I frames. Although the I frame has a larger amount of data than the P frame and B frame, since the I frame is not periodically inserted, the number of inserted I frames is reduced and the data amount of the compressed image data is reduced.

  The range to be imaged is continuously imaged at a constant cycle, and image data representing the subject image is sequentially given for each frame at a constant cycle. An I frame, a P frame, or a B frame is generated from the image data for each frame.

  The first frame at time t1 is an I frame. It is assumed that motion is detected from time t2 to time t3, from time t4 to time t5, from time t6 to time t7, and from time t8 to time t9. Then, during those times t2 to t3, between times t4 and t5, between times t6 and t7, and between times t8 and t9, an I frame is generated at a constant period. Inserted. P frames or B frames are generated and inserted between I frames.

  It is assumed that no motion is detected from time t1 to time t2, from time t3 to t4, from time t5 to time t6, and from time t7 to time t8. During those times t1 to t2, from time t3 to t4, from time t5 to time t6, and from time t7 to time t8, an I frame is not generated and a P frame or B frame is generated. Generated and inserted.

  FIG. 2 is a block diagram illustrating an electrical configuration of the imaging system.

  The imaging object is continuously imaged by the digital camera 1 at a constant period. Image data representing an image within the imaging range is sequentially output from the digital camera 1 for each frame and input to the server 2 via the network.

  Image data that is sequentially input to the server 2 for each frame is input to the motion detection device 4 via the communication interface 3. The motion detection device 4 detects the presence or absence of motion within the imaging target range. Data indicating the presence or absence of motion detection and the image data input to the server 2 are input to the MPEG encoder / decoder 5. As described above, the MPEG encoder / decoder 5 performs compression processing so that I frames are periodically inserted while motion is detected, and P frames or B frames are inserted between I frames. . While no motion is detected, an I frame is not generated, and a P frame or a B frame is generated and inserted. The compressed image data is recorded in the database 7 by the recording / reading control device 6.

  The image data recorded in the database 7 is read by the recording / reading control device 6. The read image data is expanded frame by frame by the MPEG decoder / encoder 5. The expanded image data is given to the display device 9 via the recording / reading control device 6 and the control circuit 8. An image represented by image data recorded in the database 7 is displayed on the display screen of the display device 9.

  The image data input to the server 2 is sequentially supplied to the display device 9 frame by frame via the control device 8. Images captured by the digital camera 1 are sequentially displayed on the display screen of the display device 9.

  FIG. 3 is a flowchart showing a processing procedure of the imaging system.

  As described above, the imaging target range is imaged at a constant period, and image data is input to the server frame by frame (step 11). If it is the first frame image (YES in step 12), an I frame is generated to generate a complete one frame image (step 14). If it is not the image of the first frame (NO in step 12), it is determined whether or not motion has been detected (step 13). If there is a motion (YES in step 13), an I frame is generated (step 14). If there is no motion (NO in step 13), a B frame or a P frame is generated (step 15).

  Steps 11 to 15 are repeated until the imaging is completed, for example, when the imaging system is powered off.

  FIG. 4 shows the relationship between motion detection time and detection information.

  The relationship between the motion detection time and the detection information is also stored in the database 7. Detection information is stored corresponding to the motion detection time. The server 2 is provided with a clock (not shown), and the motion detection time is detected from the clock. The motion detection time indicates the time when motion is detected after no motion during a predetermined time.

  The detection information is for estimating the content of the motion corresponding to the motion detection time. Detection information can be determined by comparing an image before motion detection with an image after motion detection. For example, the image before the motion detection is compared with the image after the motion detection, and when there is no object in the imaging range, “take away” is determined. If an object that did not exist in the image before the motion detection is present in the image after the motion detection, it is determined as “leave”. If the image before motion detection and the image after motion detection are the same, it is determined as “intrusion”.

  FIG. 5 is an example of a display window displayed on the display screen of the display device included in the server 2.

  At the upper left of the display window 20, a recorded image display window 21 for displaying a moving image represented by the image data recorded in the database 7 is formed. Under the recorded image display window 21, a slide bar 24 and a slide button 24 for determining the playback position of the moving image displayed in the recorded image display window 21 are formed. In the lower left of the slide bar 24, a playback button 22 for starting playback of the selected video, a button 23 for giving a playback command for the next video of the selected video, motion detection time and detection information of the selected video are displayed. A display area 26 is formed.

  Furthermore, animation icons 31 to 34 are formed under these buttons 22 and the like. An area 35 for displaying motion detection times of moving pictures corresponding to the moving picture icons 31 to 34 and an area 36 for displaying detection information are formed. A slide bar 37 for selecting another moving image is formed on the right side of the area.

  In the upper right of the display window 20, a window 40 for displaying an image of the imaging target area that is currently being imaged is formed. Below this window 40, a large number of thumbnail display areas 42 are formed. In these thumbnail display areas 42, there are a number of digital cameras (in FIG. 1, only one digital camera 1 is shown, but there are many digital cameras for each different imaging target area). In each case, a thumbnail image of the imaging target area currently being captured is displayed. Between the window 40 and the thumbnail display area 42, an area 41 for displaying the identification name of the digital camera that captures the moving image displayed in the window 40 is formed.

  When a desired icon among the icons 31 to 34 is clicked by the operator of the server 2, the selected moving image is displayed on the window 21.

  As described above, when the I frame is expanded, it is not necessary to use another frame. When a motion is detected, an I frame is generated. Therefore, when searching for a desired image based on the I frame, it is easy to find the desired image.

  In the above-described embodiment, hardware is used, but it may be realized using software. The above-described embodiment can be used for the imaging target region for a monitoring camera and also for a fixed-point camera that performs fixed-point observation.

It is an example of a compression method. It is a block diagram which shows the electric constitution of an imaging system. It is a flowchart which shows the process sequence of an imaging system. The relationship between motion detection time and detection information is shown. It is an example of a display window.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Server 4 Motion detection apparatus 5 MPEG decoder / encoder 6 Recording / reading control apparatus 8 Control apparatus

Claims (2)

Imaging means for continuously imaging a predetermined imaging target range at a fixed period and sequentially outputting image data representing an image in the imaging target range for each frame;
Motion determination means for inputting image data sequentially output for each frame from the imaging means, and for determining the presence or absence of movement within the imaging target range;
Of the image data sequentially output for each frame from the image pickup means, the image data representing the image of the first frame is subjected to complete compression processing so that it becomes a complete image of one frame, and the images of the remaining frames are processed. For the image data to be represented, the complete compression processing is performed in response to the determination by the motion determination means that there has been motion, and the difference information from the previous frame in response to the determination by the motion determination means that there has been no motion Compression means for performing differential information compression processing as shown, and recording control means for controlling the recording medium so as to record image data compressed by the compression means,
An imaging system comprising: The imaging means continuously captures a predetermined imaging target range at a constant cycle, and sequentially outputs image data representing an image within the imaging target range for each frame,
The motion determination means inputs the image data sequentially output from the imaging means for each frame, determines the presence or absence of movement within the imaging target range,
The compression means performs a complete compression process so that the image data representing the image of the first frame among the image data sequentially output from the imaging means for each frame becomes a complete image of one frame, and the rest The image data representing the image of the frame is subjected to the complete compression process in response to the motion determining means determining that there is motion, and the previous frame in response to the motion determining means determining that there is no motion. The difference information compression process is performed to show the difference information with
Recording control means controls the recording medium to record the image data compressed by the compression means;
An operation control method of an imaging system.

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