JP2007251540A - Image recording system and image recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image recording system and an image recording method capable of correctly compressing and elongating an image and transferring the image without securing a network of a big transfer capacity, without using a high throughput CPU or a large-scale signal processing circuit. <P>SOLUTION: The image recording method comprises the steps of: establishing a motion detection region and a compression object region at an image inputted from a camera 101; making the motion detection regions identical to an effective image pick-up region of the camera 101; making the compression object region a part of the effective image pick-up region of the camera 101; performing motion detection for a whole video signal inputted from the camera 101 at the motion detection region; performing image compression for the video signal at the compression object region; and recording it on a hard disk 212 or sending it out a network 107. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image recording system and an image recording method for monitoring applications.

  Conventionally, several methods have been proposed as image recording methods for monitoring purposes. As one of them, the video output of the camera is stored in the image data memory, and a plurality of sections are provided in the image data on the image data memory, and when the motion is detected on the image data memory, the image data memory When the image data stored in the image data memory is displayed on a monitor such as a CRT (Cathode Ray Tube) or a liquid crystal display, the image of the detected motion is enlarged. There is a method of displaying an overlapped image and a normal image in an overlapping manner (for example, see Patent Document 1).

JP 10-322684 A

  However, in the conventional image recording method, since the video output of the camera has the same resolution as the image displayed on the monitor, a huge amount of computation is required to compress the entire image, and compression and expansion are performed by software. If this is the case, a CPU (Central Processing Unit) with high processing capability is required. For this reason, the request of cost reduction cannot be answered. In this case, although it is possible to reduce the cost by using a CPU with low processing capability, the compression and decompression processing within a specified time is not completed, and frame dropping occurs. Dropping frames in surveillance applications must be avoided for that purpose. In addition, if image compression is to be performed by hardware, a large-scale signal processing circuit for compressing a high-resolution image is required, and in this case, the demand for cost reduction cannot be answered.

  Also, since a file in which the entire image is compressed is handled, when monitoring from a remote location, a network with a large transfer capacity must be secured, and the system cost requirement cannot be answered. Further, even if there is an existing network, if it does not have a sufficient transfer capacity to cope with it, the amount must be increased, and a cost for that is generated. Also, when a high-resolution compressed file is sent to a network that does not have a sufficient transfer capacity, there is a high possibility that packet loss will occur, and there is a high possibility that frames will be dropped during decompression.

  The present invention has been made in view of such circumstances, and can perform image compression and expansion without dropping frames without using a high-performance CPU or a large-scale signal processing circuit. An object of the present invention is to provide an image recording system and an image recording method capable of transferring an image without securing a network having a large transfer capacity.

The object is achieved by the following configuration or method.
The image recording system of the present invention includes a motion detection unit that performs motion detection using the entire imaging region of the imaging unit as a motion detection region, and a compression that acquires a part of the imaging region detected by the motion detection unit as a compression target region. A target area image acquisition means; an image compression means for compressing the image of the compression target area acquired by the compression target area image acquisition means; and a recording means for recording the image compressed by the image compression means. .

  With this configuration, the motion detection region and the compression target region are set in the image input from the imaging unit, the motion detection region is the same as the effective imaging region of the imaging unit, the compression target region is a part of the effective imaging region, Since motion detection is performed in the detection area and image compression is performed on the image in the compression target area, it is not necessary to compress the entire effective imaging area of the imaging means, and a huge amount of CPU computation or a large scale is required. A signal processing circuit becomes unnecessary. In addition, the size of the file stored in the recording means can be reduced, and the recording means can be used effectively.

  Further, in the image recording system of the present invention, the compression target region image acquisition unit determines a region having a motion when a motion is detected in the motion detection region, and the compression is performed at a position including the determined region. Change the target area from the default position.

  With this configuration, when motion is detected in the motion detection region, the compression target region is changed from the initial setting position to the region where the motion is determined, so that it is possible to monitor the region of interest (region where motion is detected) in a wide range. Become.

  Further, in the image recording system of the present invention, the compression target area image acquisition unit equally divides the motion detection area into N (N is an integer), and motion is detected when motion is detected in the motion detection area. It is determined where the existing region is the motion detection region divided into N equal parts, and the compression target region is changed from the initial setting position to a position including the determined region.

  With this configuration, when the motion detection area is equally divided into N (N is an integer) and the motion is detected in the motion detection area, the compression target area is changed from the initial setting position to the area where the motion is determined. It is possible to monitor a region of interest (region where motion is detected).

  Further, in the image recording system of the present invention, the compression target area image acquisition unit determines all areas where there is a motion when two or more motions are detected in the motion detection area, and each determined area The compression target area is divided so as to include image data, and the image compression unit performs image compression by combining the divided images of the compression target areas as one image.

  With this configuration, even when there are two or more movements, the compression target area is divided and assigned to each, so that image compression can be performed at a time.

  Further, in the image recording system of the present invention, the compression target area image acquisition unit holds the current amount of image data of the motion detection area and the past of a plurality of frames, and motion is detected in the motion detection area. The region where the motion is detected is determined, and the compression target region of the image data past several frames from the time when the motion is detected includes the region where the motion is detected in the image data of the corresponding frame from the initial setting position. Change to position.

  With this configuration, the image data in the motion detection area is held for the current time and the past for a plurality of frames, so that the images before and after the motion detection can be monitored.

  Further, in the image recording system of the present invention, the compression target area image acquisition means holds image data of the motion detection area for a plurality of frame periods when motion is detected in the motion detection area, It is determined whether or not the movement is moving, and if it is moving, the compression target area is changed according to the direction of the movement.

  With this configuration, when motion is detected in the motion detection region, the image data in the motion detection region is held for a plurality of frame periods, so that even if the motion moves, the compression target region can follow the motion.

  In the image recording system of the present invention, the compression target region image acquisition unit shifts the compression target region in the horizontal direction or the vertical direction within the motion detection region in accordance with an operation instruction.

  With this configuration, the compression target area is shifted in the horizontal direction or the vertical direction within the motion detection area, so that panning or tilting can be realized.

  The image recording system of the present invention can send data to a network including the Internet, and includes network control means for sending the image data of the compression target area compressed by the image compression means to the network.

  With this configuration, an image obtained by compressing only the image in the compression target area is sent to the network, so that it is not necessary to greatly increase the transmission capacity.

  In the image recording system of the present invention, the motion detection unit samples a video signal for motion detection when performing motion detection in the entire imaging region of the imaging unit.

  With this configuration, when motion detection is performed in the entire imaging region of the imaging unit, the video signal for motion detection is sampled, so that the amount of calculation for motion detection can be reduced.

  The image recording method of the present invention performs motion detection using the entire imaging region of the imaging device as a motion detection region, acquires a part of the imaged region detected as motion as a compression target region, and compresses the acquired image of the compression target region. To the recording device.

  By this method, motion detection is performed using the entire imaging area of the imaging device as a motion detection area, a part of the motion-detected imaging area is acquired as a compression target area, and an image of the acquired compression target area is compressed and recorded on a hard disk or the like Since recording is performed in the apparatus, it is not necessary to compress the entire effective imaging area of the imaging device, and a huge amount of CPU computation or a large-scale signal processing circuit is not necessary. Further, the size of the file stored in the recording device can be reduced, and the recording device such as a hard disk can be effectively used.

  Further, in the image recording method of the present invention, when motion is detected in the motion detection region, the compression target region is changed from the initial setting position to a position including a region where there is motion.

  With this method, when motion is detected in the motion detection region, the compression target region is changed from the initial setting position to the region where the motion is determined, so that it is possible to monitor the region of interest (region where the motion is detected) in a wide range. Become.

  According to the present invention, an image can be compressed and expanded without dropping frames without using a high processing capacity CPU or a large-scale signal processing circuit, and a network with a large transfer capacity can be used for remote monitoring. It is possible to provide an image recording system and an image recording method capable of transferring an image without ensuring.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a schematic configuration of an image recording system according to Embodiment 1 of the present invention. In the figure, the image recording system of the present embodiment includes a camera 101, an image storage device 102, a monitor 103, an input unit 104, and a personal computer (hereinafter referred to as a personal computer) 105. .

  The camera 101 shoots the subject 106 and includes an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and outputs a video signal. Since this system is used for monitoring purposes, there are various subjects 106 such as a person, an object, and a car in a parking lot. The image storage device 102 has a function of compressing a video signal output from the camera 101 using JPEG (Joint Photographic Experts Group) or MPEG (Moving Picture Experts Group) and recording it on a hard disk (recording device). In addition, a function for sending data to the network 107 is also provided, and the video signal from the camera 101 is compressed and sent to the network 107. In addition, when there is a data transmission request from the external device such as a personal computer (hereinafter referred to as a personal computer) through the network 107, it has a function of reading a specific video from the hard disk and transmitting it to the network 107.

  The monitor 103 displays a video signal from the camera 101, displays a video stored in the image storage device 102, and information on operation, setting change, control and maintenance of the entire system such as the camera 101 and the image storage device 102. Used for display. The input unit 104 includes a keyboard, a touch panel, button switches, and the like, and is used for command input for controlling the entire system such as the camera 101 and the image storage device 102. The personal computer 105 is connected to the network 107 and has a function of remotely operating the image storage device 102. For example, a specific video recorded on the hard disk of the image storage device 102 is read out and acquired via the network 107.

  FIG. 2 is a block diagram illustrating a schematic configuration of the image storage device 102. In the figure, an image storage apparatus 102 includes an A / D conversion unit 202, a motion detection unit 204, a frame memory 205, an image clipping unit 207, an image compression unit 208, a control unit 210, and a hard disk control unit 211. A hard disk 212, an image expansion unit 213, a display control unit 214, and a network control unit 215.

  The control unit 210 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the entire system. The video signal 201 from the camera 101 is input to the A / D conversion unit 202. The A / D conversion unit 202 digitally converts the video signal 201 and inputs it to the motion detection unit 204 and the frame memory 205 as image data. The motion detection unit 204 performs motion detection from the image data (A / D conversion output) 203 input from the A / D conversion unit 202 and inputs the result to the control unit 210. The frame memory 205 has a capacity capable of storing a plurality of image data, and functions as a first-in first-out (FIFO) that stores the image data without changing the input order.

  The image cutout unit 207 cuts out a part of the image data from the frame memory 205 as a compression target area under the control of the control unit 210 and inputs it to the image compression unit 208. The image compression unit 208 compresses the image data input from the image cutout unit 207 and inputs the compressed image data to the hard disk control unit 211. The hard disk control unit 211 stores the compressed image data (hereinafter referred to as compressed image data) input from the image compression unit 208 in the hard disk 212. Further, the hard disk control unit 211 reads out the compressed image data stored in the hard disk 212 in accordance with an instruction from the control unit 210 and inputs the compressed image data to the image expansion unit 213 or the network control unit 215. The hard disk 212 is a storage device that can store and read data. The image decompression unit 213 decompresses the compressed image data read from the hard disk control unit 211 and inputs the decompressed image data to the display control unit 214. The display control unit 214 converts the image data input from the image expansion unit 213 into a format that can be displayed on the monitor 103 (see FIG. 1) and inputs the converted format. The network control unit 215 sends the compressed image data read from the hard disk 212 to the network 107.

  The camera 101 corresponds to an imaging unit. The motion detection unit 204 and the control unit 210 constitute a motion detection unit. The frame memory 205, the image cutout unit 207, and the control unit 210 constitute a compression target area image acquisition unit. The image compression unit 208 corresponds to an image compression unit. The hard disk control unit 211 and the hard disk 212 correspond to a recording unit. The network control unit 215 corresponds to a network control unit.

  Next, the operation of the image cutout unit 207 will be described with reference to FIG. In the figure, reference numeral 301 denotes a motion detection area, which is equivalent to the effective image pickup area of the CCD of the camera 101 and includes a plurality of motion detection blocks 303. In this figure, it is composed of a total of 128 motion detection blocks, 16 in the horizontal direction and 8 in the vertical direction. Reference numeral 302 denotes an area to be compressed, which is set inside the motion detection area 301 and can be repositioned inside the motion detection area 301 under the control of the control unit 210. Normally, it is set at the center of the motion detection area 301. When a motion is detected in the motion detection area 301, the setting is changed to a position including the motion detection block 303 where the motion is detected. The plurality of motion detection blocks 303 are arranged inside the motion detection area 301 without a gap, and motion detection is performed with each as one unit.

  A motion detection area 301 and a compression target area 302 are provided in an input image from the camera 101. As described above, the motion detection area 301 is the same as the effective imaging area of the CCD of the camera 101, and performs motion detection on the entire video signal input to the CCD. The compression target area 302 is a part of the effective image pickup area of the CCD, performs image compression on the video signal input to this area, and records it on the hard disk 212 or sends it to the network 107. With this configuration, motion detection can be performed over a wider range than the image recorded on the hard disk 212.

  Further, when a motion is detected in the motion detection region 301, a region where there is a motion is determined from the detection result, and the compression target region 302 includes the region where the motion is detected from the initially set region. Change to position. By adopting such a configuration, it is not necessary to compress the entire effective imaging area of the CCD of the camera 101, and it is possible to monitor the attention area (area where motion is detected) in a wide range. Therefore, an enormous amount of CPU calculation or a large-scale signal processing circuit is not required. Furthermore, the size of the file stored in the hard disk 212 or the size of the file sent to the network 107 can be reduced.

  Further, when the image data of the motion detection area 301 is stored for a plurality of frames of the present and the past, and a motion is detected in the motion detection area 301, an area where there is motion is determined from the result, and the motion The image compression is performed by changing the compression target area of the image data several frames past from the time when the image is detected to the position including the area where the movement of the image data of the corresponding frame is detected from the initially set position. Accordingly, it is possible to monitor the images before and after the motion is detected without compressing the entire effective imaging area of the CCD of the camera 101 using a huge amount of calculation. Furthermore, the size of the file stored in the hard disk 212 or the size of the file sent to the network can be reduced.

  Next, the operation of the image storage device 102 will be described with reference to the flowchart shown in FIG. The motion detection unit 204 performs a motion detection process on the video signal 201 digitally converted by the A / D conversion unit 202 (step S401). For example, the average value of the luminance components of the A / D conversion output 203 input by motion is calculated for each motion detection block 303 (see FIG. 3), and the difference between frames is calculated. Then, the presence / absence of motion is determined from the calculated difference (step S402). When the difference is larger than a specific threshold, it is determined that “there is motion”, and when it is smaller, it is determined that there is no motion.

Here, general motion detection can be expressed by Equation (1).
AVE (m, n) −AVE (m, n−1)> TH (1)
AVE: function representing luminance average value m: motion detection block number n: frame number TH: threshold

  Note that the amount of calculation necessary for the motion detection process can be reduced by sub-sampling when calculating the average value of the luminance components.

  From the detection result of the motion detection unit 204, the control unit 210 transitions to step S403 if there is motion, and transitions to step S405 if there is no motion. If there is a motion in the determination result in step S <b> 402, the control unit 210 recognizes the position of the motion detection block 303 where the motion is detected from the output result of the motion detection unit 204, and the image clipping unit 207 determines the compression target region. An area to be cut out is determined (step S403). The control unit 210 reads the result of step S403, recognizes the position of the motion detection block having motion, and changes the setting of the compression target region of the image cutout unit 207 so as to include the motion detection block having motion. (Step S404). Details of the cutout area determination will be described separately.

  After the setting change to the image clipping unit 207 in step S404 is completed, the control unit 210 reads out the frame memory 205 in order to cut out the compression target region from the motion detection region (an effective imaging region of an image sensor such as a CCD). Is performed (step S406). The frame memory 205 is configured to hold a plurality of frames of images. By adopting such a configuration, the compression target area is changed with respect to the frame 205 that goes back several frames from the frame in which the motion is detected by the motion detection unit 204, and the images before and after the motion are detected are stored on the hard disk. Recorded at 212 or made visible to the operator. Here, details of the frame memory 205 and the functional blocks before and after the frame memory 205 will be described separately.

  The control unit 210 outputs a control signal to the image cutout unit 207 whose setting has been changed in step S404, and cuts out the output image of the frame memory 205 read out in step S406 (step S407). The control unit 210 outputs a control signal to the image compression unit 208, and performs image compression by capturing the image cut out in step S407 (step S408). Here, the details of image region extraction and image compression will be described separately.

  The control unit 210 controls the hard disk control unit 211 to add a unique header or the like to the compressed image data output from the image compression unit 208 or register it in the file system. (Step S409). The controller 210 stores the data prepared in step S409 in the hard disk 212 (step S410). Thereafter, the control unit 210 transitions again to step S401. If no motion is detected in step S402, it is not necessary to change the setting of the compression target area, or the setting of the compression target area needs to be restored to the initial setting. The same value as the initial setting is set (step S405). Thereafter, the control unit 210 transitions to step S406.

<Description of cutout area determination>
In the following, the determination of the cutout region will be described by taking the case of one moving region and the case of two moving regions as examples.

  An example in the case where there is one moving area will be described with reference to FIG. Reference numeral 501 denotes a motion detection area, which is equivalent to the effective pixel area of the CCD of the camera 101. Reference numeral 502 denotes a compression target area at the time of initial setting, and is located in the center of the motion detection area 501. The compression target area when the apparatus is activated or when no motion is detected is set at this position. Reference numeral 503 denotes a motion detection block having motion, and its position is (C1, R6). Reference numeral 504 denotes a compression target area after the setting is changed, and the setting is changed so as to include a motion detection block 503 having motion.

  The control unit 210 reads the output result of the motion detection unit 204 and recognizes the position of the motion detection block in which there is motion. When recognizing that the motion detection block in which the motion is detected is only the detection block 503 and the position is only (C1, R6), the compression target area 502 at the time of initial setting includes (C1, R6). Therefore, it is determined that the compression target area 502 needs to be changed, and is set to the compression target area 504 after the setting change including (C1, R6).

  Next, an example in which there are two moving regions at positions away from each other will be described with reference to FIG. Reference numeral 601 denotes a motion detection area, which is equivalent to the effective pixel area of the CCD of the camera 101. Reference numeral 602 denotes a compression target area at the time of initial setting, and the position thereof is located at the center of the motion detection area 601. The compression target area when the apparatus is activated or when no motion is detected is set at this position. Reference numeral 603 denotes a motion detection block A having motion, and its position is (C1, R6). Reference numeral 604 denotes a motion detection block B having motion, and its position is (C3, R2). Reference numeral 605 denotes the compression target area A after the setting change, and is set so as to include a motion detection block A603 having motion. Reference numeral 606 denotes a compression target area B after the setting is changed, and is set so as to include a motion detection block B604 having motion.

  The control unit 210 reads the output result of the motion detection unit 204 and recognizes the position of the motion detection block in which there is motion. In this case, it is recognized that the motion detection blocks in which motion is detected are the motion detection block A603 and the motion detection block B604, and their positions are (C1, R6) and (C3, R2). Here, it is determined that the positions (C1, R6) and (C3, R2) are separated from each other, and that one motion target block cannot include both motion detection blocks. That is, since (C1, R6) and (C3, R2) are not included in the compression target area 602 at the time of initial setting, it is determined that the compression target area needs to be changed, and two compression target areas are set. . One is the compression target area A605 after the setting change including (C1, R6), and the other is the compression target area B606 after the setting change including (C3, R2). Detection block A603 and motion detection block B604 are set to be included.

<Description of Timing of Frame Memory 205 and Functional Blocks Before and After>
An example in which the delay of the frame memory 205 is 3 frames will be described with reference to FIG.

  FIG. 7 is a timing chart showing the timing of the output signals of the frame memory 205 and the functional blocks before and after it. From the upper stage, the timings of the A / D conversion output 203, the output result of the motion detection unit 204, the frame memory output 206, the compression target region change control signal from the control unit 210, the image cutout output 218, and the compressed image output 209 are framed. Shown in unit timing. The number described in each video signal indicates a frame number.

  When the A / D conversion output 203 is sequentially output and motion is detected with the frame number (N), the motion detection unit 204 has motion in the next frame to which the video signal with the frame number (N) is input. Is detected, and the detection result is output. The frame memory 205 has three frame memories inside, and the delay from input is three frames. Therefore, the frame number of the frame memory output 206 at the timing when the motion detection result of the motion detection unit 204 is output is (N-2).

<Explanation of image area clipping and image compression>
Next, the image region cut-out processing and the image compression processing will be described using an example in which there is one moving region and two moving regions at positions away from each other.

When there is one motion region The control unit 210 outputs a control signal for changing the compression target region from the output result of the motion detection unit 204 within the same frame time, and the compression target cut out by the image cutout unit 207 Change the region settings. Under the control of the control unit 210, the image cutout unit 207 changes the setting of the compression target area. The frame number of the video signal that reflects the setting change is (N-2). The image compression unit 208 captures the output signal of the image cutout unit 207 and performs image compression. The frame number of the compressed image output 209 that reflects the change of the compression target area output from the image compression unit 208 is (N-2). Therefore, in the configuration of the present embodiment, the setting change of the compression target area is reflected from the video signal of the frame number (N-2) two frames before the frame number (N) where the motion has occurred, and the motion is An image including a motion detection block in which motion is detected from two frames before detection is compressed.

FIG. 8 shows an example of an image output from the image cutout unit 207 when there are two moving regions at positions away from each other. As described with reference to FIG. 6, when there are two motion-detected areas separated from each other in the motion detection area, both videos must be compressed and stored in the hard disk 212. In this embodiment, the compression target area A 605 after the setting change and the compression target area B 606 after the setting change in FIG. 6 are cut out and pasted together as one image and input to the image compression unit 208. As shown in FIG. 6, the compression target area A605 after the setting change is half the area of the compression target area 602, and the compression target area B606 after the setting change is also half the area of the compression target area 602. Therefore, the image cutout unit 207 reads the two compression target areas A605 and B606 so as to connect them. Reference numeral 801 denotes the compression target area A after the setting change, and is the compression target area A605 after the setting change shown in FIG. Reference numeral 802 denotes the compression target area B after the setting change, and is the compression target area B 606 after the setting change shown in FIG.

<Description of read operation>
Next, an example of the reading operation of the image recording system according to the present embodiment will be described. FIG. 9 is a flowchart for explaining an example of the read operation. The user operates the input unit 104 to input a control signal to the control unit 210 so as to read an image at a desired time. The control unit 210 inputs a control signal to the hard disk control unit 211. The hard disk control unit 211 prepares to read an image at a time designated by the user from the hard disk 212 (step S901). The compressed image data at the time designated by the user is read from the hard disk 212 and input to the image expansion unit 213 (step S902). The control unit 210 activates the image expansion unit 213. The image decompression unit 213 performs decompression processing on the compressed image data input from the hard disk control unit 211, and inputs the decompressed image to the display control unit 214 (step S903). The control unit 210 activates the display control unit 214. The display control unit 214 converts the image input from the image expansion unit 213 into a format necessary for display on the monitor 103 and outputs the converted format. The monitor 103 receives the display output 216 from the display control unit 214 and displays an image at a time desired by the user (step S904).

<Description of network transmission operation>
Next, an example of network transmission operation of the image recording system according to the present embodiment will be described. FIG. 10 is a flowchart for explaining an example of the network transmission operation. The user operates the personal computer 105 and inputs a control signal to the control unit 210 via the network 107 so as to read an image at a desired time. The control unit 210 inputs a control signal to the hard disk control unit 211. The hard disk control unit 211 prepares to read an image at a time designated by the user from the hard disk 212 (step S1001). Then, the compressed image data at the time designated by the user is read from the hard disk 212 and input to the network control unit 215 (step S1002). The control unit 210 activates the network control unit 215. The network control unit 215 prepares a format for sending the compressed image data input from the hard disk control unit 211 to the network 107, and sends it to the network 107 (step S1003). The personal computer 105 receives the compressed image data sent to the network 107, decompresses the image using image decompression software installed in the personal computer 105, and displays it on the monitor of the personal computer 105 (step S1004).

  As described above, according to the image recording system of the present embodiment, the motion detection area and the compression target area are set in the image input from the camera 101, and the motion detection area is set to be the same as the effective imaging area of the CCD of the camera 101. The compression target area is a part of the effective imaging area of the CCD, the motion detection is performed on the entire video signal input from the CCD in the motion detection area, and the image of the video signal is compressed in the compression target area and stored in the hard disk 212. Since it is recorded or sent to the network 107, it is not necessary to compress the entire effective imaging area of the CCD of the camera 101, and an enormous amount of CPU computation or a large-scale signal processing circuit is not required. In addition, the size of the file stored in the hard disk 212 or the size of the file sent to the network 107 can be reduced, so that the hard disk 212 can be used effectively and the transmission capacity does not need to be greatly increased.

(Embodiment 2)
Next, an image recording system according to Embodiment 2 of the present invention will be described. FIG. 11 is a diagram for explaining compression target area control based on motion prediction of the image recording system according to the present embodiment. Since the system configuration is the same as that of the first embodiment, FIG. 2 is used. In FIG. 11, reference numeral 1101 denotes a motion detection area, and the three motion detection areas are the same. A description will be given assuming that the current frame number is (N). Reference numeral 1102 denotes a motion detection position (N-3), which is the position of a motion detection block in which motion has been detected three frames before the current frame. Reference numeral 1103 denotes a motion detection position (N-2), which is the position of a motion detection block in which motion is detected two frames before the current frame. Reference numeral 1104 denotes a motion detection result (N-1), which is the position of the motion detection block in which motion is detected one frame before the current frame.

  Reference numeral 1105 denotes a motion vector (N-2), which represents the difference between the coordinate positions of the motion detection position (N-3) 1102 and the motion detection position (N-2) 1103 as a vector. . Reference numeral 1106 denotes a motion vector (N−1), which represents the difference between the coordinate positions of the motion detection position (N−2) 1103 and the motion detection position (N−1) 1103 as a vector. . Reference numeral 1007 denotes an expected vector, which is calculated from a motion vector (N-2) and a motion vector (N-1). An example of a calculation formula for the predicted vector 1007 is shown in the following formula (2).

VP (N) = (V (N−1) + V (N−2)) / 2 Formula (2)
VP (N): Expected vector in N frame V (N): Motion vector in N frame

  Reference numeral 1108 denotes a predicted motion block, which is a motion detection block in which the end of the predicted vector 1107 is located. In this embodiment, it is the motion detection block position (C2, R4). Reference numeral 1109 denotes a compression target area, and is set so as to include the predicted motion block 1108 obtained by the predicted vector 1107 at the center. Reference numeral 1110 denotes an expected motion area.

  The control unit 210 holds the motion detection result output from the motion detection unit 204 for three frame periods. Then, a predicted vector 1107 is calculated from the motion vector (N−2) 1105 and the motion vector (N−1) 1106. Since the motion detection block where the end of the predicted vector 1106 is located is (C2, R4), the control unit 210 outputs a control signal to the image cutout unit 207 to change the setting of the compression target region. In this way, by calculating the predicted motion block using the motion vector, it is possible to capture a monitoring target having a motion in the center of the compression target area, compress the image, and record it on the hard disk 212.

(Embodiment 3)
Next, an image recording system according to Embodiment 3 of the present invention will be described. FIG. 12 is a block diagram showing a schematic configuration of the image storage apparatus 1200 of the image recording system according to the present embodiment. This embodiment is characterized in that it has pan and tilt functions. In the figure, an image storage apparatus 1200 includes an A / D conversion unit 1202, a wide area frame memory 1203, a first image cutout unit 1204, a motion detection unit 1205, a frame memory 1206, and a second image cutout unit 1207. The image compression unit 1208, the control unit 1209, the hard disk control unit 1210, the hard disk 1211, the image expansion unit 1212, the display control unit 1213, and the network control unit 1214 are configured.

  In FIG. 12, reference numeral 1201 denotes a wide area video input, which is a video signal taken by the camera 101. The camera 101 of this embodiment is equipped with a wide-angle lens that can capture a wide field of view, captures a wide-field image in one frame (or field) period, and outputs a video signal. Note that the image pickup device such as a CCD mounted on the camera 101 may be a single image pickup device that can pick up an image signal with a wide field of view, or an image pickup device formed of a plurality of CCDs.

  The control unit 1209 includes a CPU, a ROM, a RAM, and the like, and controls the entire system. The A / D converter 1202 digitally converts the wide area video input 1201 that is an analog signal. The wide area frame memory 1203 temporarily stores the image data input from the A / D conversion unit 1202. The first image cutout unit 1204 can cut out an arbitrary motion detection region from image data stored in the wide area frame memory 1203 in accordance with control from the control unit 1209. The motion detection unit 1205 performs motion detection on the motion detection region cut out by the first image cutout unit 1204 and inputs the result to the control unit 1209. The frame memory 1206 has a capacity capable of storing a plurality of motion detection areas cut out by the first image cutout unit 1204, and stores a first-in first-FIFO that stores image data without changing the order in which the image data is input. Out).

  The second image cutout unit 1207 cuts out a part of the output of the frame memory 1206 as a compression target area in accordance with the control from the control unit 1209 and inputs it to the image compression unit 1208. The image compression unit 1208 compresses the output image of the second image cutout unit 1207 and inputs it to the hard disk control unit 1210. The hard disk control unit 1210 stores the compressed image data output from the image compression unit 1208 in the hard disk 1211. Further, the image data stored in the hard disk 1211 is read out and input to the image expansion unit 1211 or the network control unit 1214.

  A hard disk 1211 is a recording device capable of storing and reading data. The image decompression unit 1212 decompresses the compressed image data input from the hard disk control unit 1210 and inputs it to the display control unit 1213. The display control unit 1213 converts the image data expanded by the expansion unit 1212 into a format that can be displayed on the monitor 103 and outputs the converted data. The network control unit 1214 sends the compressed image data read from the hard disk 1211 by the hard disk control unit 1210 to the network 107.

  Next, the operation of the present embodiment will be described with reference to FIGS. The control unit 1209 determines whether to perform panning or tilting (step S1301). If panning or tilting is to be performed, the process proceeds to step S1302. If not, the process proceeds to step S1304. The control unit 1209 calculates a region from which the motion detection region is cut out from the panning and tilting directions and sizes, and outputs a control signal to the first image cutout unit 1204 (step S1302). The control unit 1209 sets the position of the motion detection area 1402 after panning and tilting calculated in step S1302 in the first image clipping unit 1204 (step S1303). The details of the control of the first image cutout unit 1204 for realizing the pan and tilt functions will be described separately.

  The control unit 1209 reads out the video signal of the wide area imaging region 1401 (see FIG. 14) stored in the wide area frame memory unit 1203 and inputs it to the first image cutout unit 1204 (step S1304). The control unit 1209 cuts out the motion detection region 1402 from the wide area imaging region 1401 read out in step S1304 by the first image cutout unit 1204 according to the setting set in step S1303 (step S1305). The control unit 1209 performs motion detection on the motion detection region 1402 cut out in step S1305 by the motion detection unit 1205 (step S1306). The control unit 1209 determines whether or not a motion is detected in the motion detection area 1402 based on the motion detection result in step S1306 (step S1307). If there is a movement, the process proceeds to step S1308; otherwise, the process proceeds to step S1309.

  The control unit 1209 calculates the position of the compression target area 1403 according to the motion detection result detected in step S1306 (step S1308). The control unit 1209 changes the setting of the second image cutout unit 1207 according to the position of the compression target area 1403 calculated in step S1308 (step S1310). The control unit 1209 reads the video signal of the motion detection area 1402 stored in the frame memory 1206, and inputs it to the second image cutout unit 1207 (step S1311). The control unit 1209 cuts out the compression target region 1403 from the motion detection region 1402 read out in step S1311 by the second image cutout unit 1207 according to the setting in step S1310, and inputs it to the image compression unit 1208 (step S1312).

  The control unit 1209 compresses the image signal of the compression target area 1403 cut out in step S1312 by the image compression unit 1208 and inputs the compressed image signal to the hard disk control unit 1210 (step S1313). The control unit 1209 controls the hard disk control unit 1210 to add a unique header or the like to the compressed image data output from the image compression unit 1208 or register the file in the file system. Is performed (step S1314).

  Next, the control unit 1209 stores the data prepared in step S1314 in the hard disk 1211 (step S1315). Thereafter, the control unit 1209 transitions to step S1301 again. If no motion is detected in step S1307, it is not necessary to change the setting of the compression target area, or it is necessary to return the setting of the compression target area to the initial setting, so a control signal to the image clipping unit 1207 is sent. The same value as the initial setting is set (step S1309). Thereafter, the control unit 1209 makes a transition to Step S1311.

<Description of Control of First Image Clipping Unit 1204 Realizing Pan and Tilt Functions>
Control of the first image cutout unit 1204 that realizes the pan and tilt functions will be described.

  In FIG. 14, reference numeral 1401 denotes a wide area imaging area, which is equivalent to an effective imaging area of an image sensor constituted by a CCD or the like. In this embodiment, the wide area imaging area 1401 is divided into a total of 128 areas, 16 in the horizontal direction and 8 in the vertical direction. The first image cutout unit 1204 can cut out the motion detection area 1402 for each division unit under the control of the control unit 1209. The motion detection area 1402 can be set for each division unit of the wide area imaging area 1401, and panning and tilting can be performed by changing the setting of the motion detection area 1402. The motion detection area 1402 is an area where motion detection is performed, and motion detection is performed by the motion detection unit 1205. The motion detection area 1402 is divided into a total of 128 areas, 16 in the horizontal direction and 8 in the vertical direction. A compression target area 1403 can be set for each division unit. The compression target area 1403 is cut out by the second image cutout unit 1207 and is compressed by the image compression unit 1208.

  Reference numeral 1404 denotes a pan direction, which is information instructed by the control unit 1209 to the first image cutout unit 1204. In the present embodiment, the left end of the motion detection area 1402 is moved from (P7) to (P3). . Reference numeral 1405 denotes a tilt direction, which is information instructed by the control unit 1209 to the first image cutout unit 1204. In the present embodiment, the upper end of the motion detection area 1402 is moved from (T3) to (T1). . Reference numeral 1406 denotes a motion detection area before the setting change, and reference numeral 1407 denotes a motion detection area after the setting change. As described above, panning and tilting can be realized by changing the position of the motion detection area 1402 cut out from the wide-area imaging area 1401 by changing the setting of the first image cutout unit 1204.

  The present invention can compress and decompress images without dropping frames without using a high-performance CPU or a large-scale signal processing circuit, and secure a large transfer capacity network for remote monitoring. Therefore, the present invention can be applied to an image recording system for monitoring.

1 is a block diagram showing a schematic configuration of an image recording system according to Embodiment 1 of the present invention. 1 is a block diagram showing a schematic configuration of an image storage device in an image recording system according to Embodiment 1 of the present invention. The figure for demonstrating operation | movement of the image clipping part of the image storage apparatus in the image recording system which concerns on Embodiment 1 of this invention. Flowchart for explaining the operation of the image storage device in the image recording system according to the first embodiment of the present invention. The figure for demonstrating operation | movement when the motion area of the image clipping part of the image storage device in the image recording system which concerns on Embodiment 1 of this invention is one place. The figure for demonstrating operation | movement when the motion area of the image cutout part of the image storage device in the image recording system which concerns on Embodiment 1 of this invention exists in the position which left two places. FIG. 3 is a timing chart showing the timing of output signals from the frame memory of the image storage device and the front and rear portions thereof in the image recording system according to the first embodiment of the present invention. The figure which shows an example of an output image when there exist two places in the position where the movement area | region separated in the image clipping part of the image storage device in the image recording system which concerns on Embodiment 1 of this invention. Flowchart for explaining an image data reading operation of the image recording system according to the first embodiment of the present invention. Flowchart for explaining a network transmission operation of the image recording system according to the first embodiment of the present invention. The figure for demonstrating the compression object area | region control by the motion estimation of the image recording system which concerns on Embodiment 2 of this invention. FIG. 5 is a block diagram showing a schematic configuration of an image storage device in an image recording system according to Embodiment 3 of the present invention. Flowchart for explaining the operation of the image storage device in the image recording system according to the third embodiment of the present invention. The figure for demonstrating pan and tilt operation | movement of the image storage apparatus in the image recording system which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Camera 102, 1200 Image storage device 103 Monitor 104 Input part 105 Personal computer 106 Subject 107 Network 202, 1202 A / D conversion part 204, 1205 Motion detection part 205, 1206 Frame memory 207 Image clipping part 208, 1208 Image compression part 210, 1209 Control unit 211, 1210 Hard disk control unit 212, 1211 Hard disk 213, 1212 Image decompression unit 214, 1213 Display control unit 215, 1214 Network control unit 1203 Wide area frame memory 1204 First image clipping unit 1207 Second image clipping unit

Claims (11)

Motion detection means for performing motion detection using the entire imaging area of the imaging means as a motion detection area;
Compression target area image acquisition means for acquiring a part of the imaging area detected by the motion detection means as a compression target area;
Image compression means for compressing the image of the compression target area acquired by the compression target area image acquisition means;
Recording means for recording the image compressed by the image compression means;
An image recording system comprising:   The compression target region image acquisition unit determines a region having a motion when a motion is detected in the motion detection region, and changes the compression target region from an initial setting position to a position including the determined region. Item 8. The image recording system according to Item 1.   The compression target region image acquisition means divides the motion detection region into N equal parts (N is an integer), and when motion is detected in the motion detection region, the region where the motion has been divided into N equal parts. The image recording system according to claim 2, wherein it is determined where the motion detection area is, and the compression target area is changed from an initial setting position to a position including the determined area. The compression target area image acquisition means determines all areas where there is motion when two or more motions are detected in the motion detection area, and divides the compression target area to include each determined area And
4. The image recording system according to claim 2, wherein the image compression unit performs image compression by synthesizing the divided images of the compression target areas as one image.   The compression target area image acquisition unit holds the current data and the past data of a plurality of frames of the image data of the motion detection area, and determines a region where there is motion when motion is detected in the motion detection area. 3. The compression target area of image data that is several frames past the time when motion is detected is changed from an initial position to a position that includes an area in which motion in the image data of the corresponding frame is detected. 5. The image recording system according to any one of 4 above.   The compression target area image acquisition means holds the image data of the motion detection area for a plurality of frame periods when a motion is detected in the motion detection area, and determines whether the movement is moving in the motion detection area. And when moving, the image recording system according to any one of claims 2 to 5, wherein the compression target area is changed according to the direction of the movement.   The image recording system according to any one of claims 2 to 6, wherein the compression target area image obtaining unit shifts the compression target area in a horizontal direction or a vertical direction within the motion detection area in accordance with an operation instruction.   8. The network control unit according to claim 1, further comprising a network control unit capable of transmitting data to a network including the Internet and transmitting the image data of the compression target area compressed by the image compression unit to the network. The image recording system described.   The image recording system according to claim 1, wherein the motion detection unit samples a video signal for motion detection when performing motion detection in the entire imaging region of the imaging unit.   An image that performs motion detection using the entire imaging area of the imaging device as a motion detection area, acquires a part of the imaging area that has been detected as a compression target area, and compresses the acquired image of the compression target area and records it in a recording device Recording method.   The image recording method according to claim 10, wherein when a motion is detected in the motion detection area, the compression target area is changed from an initial setting position to a position including an area where there is a motion.

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