JP4464719B2 - Image data transmission system - Google Patents

Description

  The present invention relates to an image data transmission system such as a surveillance camera system, and more particularly to an image data transmission system that compresses and encodes a plurality of video data and transmits them through a communication network.

  In recent years, surveillance camera systems in which image data is compressed and encoded and monitored by a playback terminal located remotely via a communication network or the like have been put into practical use. In such a system, by using a compression coding method such as MPEG (Moving Picture Experts Group), it is possible to transmit image data with good image quality with a small transmission band.

  On the other hand, a system has been proposed in which images from a plurality of cameras are used to detect and monitor an image of a changed portion by the planar projection stereo method (see, for example, Patent Document 1). Also, by using the object recognition function technology that associates points and lines between two images taken with a stereo camera and estimates the positions of the points and lines in the actual scene space (three-dimensional space), A system for monitoring by recognizing the depth of the image has also been proposed (see, for example, Patent Document 2).

JP 2002-145072 A

Japanese Patent Laid-Open No. 10-42273

  As described above, when an object is recognized with high accuracy using a stereo camera, high calculation processing capability is required. If image processing such as a camera and an object recognition function is configured as a pair, it is necessary to use a CPU (Central Processing Unit) having high processing capability or to develop an ASIC (Application Specific Integrated Circuit), which causes a cost problem.

  Therefore, it is possible to reduce the cost by sending the camera image to a device with high processing capability such as a personal computer or workstation via a communication network, and to perform image processing such as object recognition function. The processing unit can be easily changed.

  On the other hand, when an image is transmitted through a communication network, a compression coding method such as MPEG using a plurality of pictures as one GOP (Group of Picture) is used. Therefore, one of the images captured at the same time is an I picture. The amount of image information differs such that one is a B picture (bidirectional predictive coded image) in (intra-frame coded image). Therefore, when the encoded images having different image information amounts are demodulated to perform the planar projection stereo method or the association of points and lines, image processing such as an object recognition function cannot be performed with high accuracy.

  An object of the present invention is an image data transmission system that compresses and encodes a plurality of video data and transmits the data via a communication network, and provides an image data transmission system that can accurately perform image processing such as an object recognition function. There is.

  In order to solve the above-described problems, the present invention provides an imaging unit that converts an optical signal imaged by an optical system into an electrical signal and outputs the electrical signal, a driving unit that drives the imaging unit, and an output from the imaging unit. Image signal processing means for subjecting the image signal to image processing and outputting the image data as image data; and image signal compression means for compressing and encoding the image data output from the image signal processing means and outputting the image data as compression encoded image data; A plurality of image data transmission apparatuses each configured by a communication means for transmitting the compressed encoded image data output from the image signal compression means to another apparatus via a communication network, and at a desired timing An image data transmission system having synchronization signal generating means for generating a synchronization signal, wherein the image signal pressure of each of the plurality of image data transmission devices It means, and performing compression coding to have the same GOP structure at the same time in accordance with the said synchronization signal from said synchronization signal generating means.

  According to another aspect of the present invention, there is provided an imaging unit that converts an optical signal imaged by an optical system into an electrical signal and outputs the electrical signal, a driving unit that drives the imaging element, and the image signal output from the imaging element. Image signal processing means for performing image processing and outputting as image data, image signal compression means for compressing and encoding the image data output from the image signal processing means and outputting the compressed encoded image data, and the image signal compression means And a communication means for transmitting the compressed and encoded image data output from the communication device to another device via a communication network, and a plurality of image data transmitting devices each configured, and synchronization for generating a synchronization signal at a desired timing An image data transmission system including a signal generation unit, wherein the image signal compression unit of each of the plurality of image data transmission devices is a GOP pin. And performing compression coding of the I picture at the same time in accordance with the said synchronization signal from and the synchronizing signal generating means in the GOP structure as a common multiple of the number of tea is n (a positive integer).

  According to the present invention, an image data transmission system that compresses and encodes a plurality of video data and transmits the data via a communication network, and obtains an image data transmission system capable of performing image processing such as an object recognition function with high accuracy. Can do.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of an image data transmission system according to the present invention. In FIG. 1, 101 is an image sensor such as a charge coupled device (CCD), 102 is a drive unit, 103 is an image signal processing unit, 104 is an image signal compression unit, and 105 is a communication unit. Reference numeral 106 surrounded by a dotted line composed of 101, 102, 103, 104, and 105 is a camera. Reference numeral 107 denotes a camera having the same configuration as the camera 106, 108 denotes a synchronization signal generation unit, 109 denotes a communication network, and 110 denotes an object recognition processing unit.

  The image sensor 101 converts an optical signal in which a subject image is formed by an optical system into an electrical signal, and outputs it as an image signal. Here, the time accumulated in each photodiode of the image sensor 101 is controlled by a pulse generated by the drive unit 102, and similarly, an image signal is read and output at a desired timing by a pulse generated by the drive unit 102. The image signal processing unit 103 performs image processing such as generating a color signal and a luminance signal on the image signal output from the image sensor 101 and outputs the image signal as image data.

  The image signal compression unit 104 performs compression encoding on the image data output from the image signal processing unit 103 using a compression encoding method such as MPEG, and outputs the result as compression encoded image data. The compression-encoded image data output from the image signal compression unit 104 is input to the communication unit 105 and transmitted to the remote object recognition processing unit 110 via the communication network 109. Here, the camera 107 is configured in the same manner as the camera 106 and performs the same operation. The number of cameras connected to the communication network 109 is not limited to the two illustrated, and may be a plurality of three or more.

  The object recognition processing unit 110 demodulates desired transmitted compression-encoded image data, detects an image of a changed portion by the planar projection stereo method, or points or lines between two images captured by a stereo camera. The object recognition is performed by calculating the depth of the object using a technique for estimating the positions of points and lines in the actual scene space (three-dimensional space).

  In FIG. 1, a synchronization signal generation unit 108 is a generation unit that generates a GOP synchronization reference signal that is a synchronization signal for controlling the operation of the image signal compression units of the cameras 106 and 107.

  In FIG. 1, the synchronization signal generation unit 108 is disposed on the camera 106, 107 side with respect to the communication network 109, but is disposed on the object recognition processing unit 110 side to transmit the synchronization signal via the communication network 109. You may make it transmit to each image signal compression part of the cameras 106 and 107. FIG.

  Next, the first method for synchronizing the switching of the GOP with respect to the operations of the camera 106, the camera 107, and the synchronization signal generator 108 will be described with reference to FIG. In FIG. 2, 201 is image data compression-encoded by the camera 106, 202 is image data compression-encoded by the camera 107, and 203 is a GOP synchronization matching reference signal output from the synchronization signal generator 108. Here, for each camera 106 and 107, one GOP is composed of 15 pictures consisting of I, B, B, P, B, B, P, B, B, P, B, B, P, B, and B. It is assumed that it has a GOP structure. Further, as shown in FIG. 2, it is assumed that the GOP of the image data 202 and the image data 203 is out of synchronization.

  In the image data 201, it is assumed that the GOP synchronization reference signal 203 is output from the synchronization signal generator 108 at time t2 after the time T1 has elapsed from the GOP switching time at time t0. Assuming that the number of pictures compression-encoded during time T1 at time t2 is P1, the image signal compression unit 104 of the camera 106 has P1 as the number of pictures of the next GOP to which the GOP synchronization reference signal 203 is input. Compression encoding is performed so that After that, at time t3, the image signal compression unit 104 of the camera 106 performs compression coding so that the number of pictures of the next GOP becomes 15.

  In the image data 202, it is assumed that the GOP synchronization reference signal 203 is output from the synchronization signal generator 108 at time t2 after the time T2 has elapsed from the GOP switching time at time t1. Assuming that the number of pictures compression-encoded during time T2 at time t2 is P2, the image signal compression unit of the camera 107 has P2 as the number of pictures of the next GOP to which the GOP synchronization reference signal 203 is input. Thus, compression encoding is performed. Thereafter, at time t3, the image signal compression unit of the camera 107 performs compression coding so that the number of pictures in the next GOP becomes 15.

  By the above operation, the image data 201 and the image data 202 have the same GOP structure after the same time t3, and the GOPs are switched in synchronization. At this time, in one GOP immediately after the GOP synchronization alignment reference signal 203 is input, only the P1 and P2 I pictures may be encoded in the image signal compression units of the cameras 106 and 107, respectively.

  With this operation, image data captured at the same time by a plurality of cameras can be compression-encoded with an equivalent image code amount.

  Next, the second method of synchronizing the switching of GOPs with respect to the operations of the camera 106, the camera 107, and the synchronization signal generator 108 will be described with reference to FIG. In FIG. 3, 301 is image data compression-encoded by the camera 106, 302 is image data compression-encoded by the camera 107, and 303 is a GOP synchronization matching reference signal output from the synchronization signal generator 108. Here, the GOP of the camera 106 is composed of 15 pictures, and the GOP of the camera 107 is composed of 30 pictures. Further, as shown in FIG. 3, it is assumed that the GOP of the image data 202 and the image data 203 is out of synchronization.

  In the image data 301, it is assumed that the GOP synchronization reference signal 303 is output from the synchronization signal generator 108 at time t2 after the time T1 has elapsed from the GOP switching time at time t0. Assuming that the number of pictures compression-encoded during time T1 at time t2 is P1, the image signal compression unit 104 of the camera 106 has the number of pictures of the next GOP to which the GOP synchronization alignment reference signal 303 is input as P1. Compression encoding is performed so that After that, at time t3, the image signal compression unit 104 of the camera 106 performs compression coding so that the number of pictures of the next GOP becomes 15.

  In the image data 302, it is assumed that the GOP synchronization reference signal 303 is output from the synchronization signal generator 108 at time t2 after time T2 has elapsed from the GOP switching time at time t1. Assuming that the number of pictures compression-encoded during time T2 at time t2 is P2, the image signal compression unit of the camera 107 has P2 pictures for the next GOP to which the GOP synchronization reference signal 303 is input. Thus, compression encoding is performed. Thereafter, at time t3, the image signal compression unit of the camera 107 performs compression coding so that the number of the next picture becomes 30.

  By the above operation, the GOP is switched in synchronization between the image data 201 and the image data 202 after the same time t3. At this time, one GOP immediately after the GOP synchronization matching reference signal 303 is input may encode only P1 and P2 I pictures in the image signal compression units of the cameras 106 and 107, respectively.

  By performing such an operation, in the plurality of cameras 106 and 107, encoding is performed so that the GOP structure has a GOP structure in which the number of GOP pictures is a common multiple of a certain number n (a positive integer). The I picture is encoded at the same time in all the cameras with the maximum number of periods. That is, in a plurality of cameras, image data captured at the same time in the cycle of the maximum number of GOP pictures can be compressed and encoded with an equivalent image code amount.

  Next, a third method for synchronizing the switching of GOPs with respect to the operations of the camera 106, the camera 107, and the synchronization signal generator 108 will be described with reference to FIG. In FIG. 4, 401 is image data compression-encoded by the camera 106, 402 is still image data compression-encoded by the camera 107, 403 is a GOP synchronization reference signal output from the synchronization signal generator 108, and 404 is This is the frame count number counted by the camera 107. Here, it is assumed that the GOP of the camera 106 is composed of 15 pictures. The camera 107 repeats counting every 15 frames, and takes a still image with a count number of 1. In FIG. 4, it is assumed that the switching from the count number 15 to 1 and the GOP switching of the camera 106 are different.

  In the image data 401, it is assumed that the GOP synchronization matching reference signal 403 is output from the synchronization signal generator 108 at time t2 after the time T1 has elapsed from the GOP switching time at time t0. When the number of pictures compression-encoded during time T1 at time t2 is P1, the camera 106 performs compression encoding so that the number of pictures of the next GOP to which the GOP synchronization reference signal 403 is input is P1. I do. Thereafter, at time t3, the camera 106 performs compression coding so that the number of pictures of the next GOP becomes 15.

  In the image data 402, it is assumed that the GOP synchronization matching reference signal 403 is output from the synchronization signal generation unit 108 at time t2 after time T2 has elapsed from the count switching time at time t1. Assuming that the count number counted during time T2 at time t2 is P2, the camera 107 counts so that the next count number to which the GOP synchronization alignment reference signal 403 is input is up to P2. Thereafter, the camera 107 repeats the count number 15 after time t3.

  With the above operation, a still image of the image data 402 is generated when an I picture of the image data 401 is generated. At this time, one GOP immediately after the GOP synchronization reference signal 403 is input in the image data 401 may encode only P1 I pictures. That is, in a plurality of cameras in which a moving image and a still image are mixed, image data captured at the same time in the cycle of the maximum number of GOP pictures of the moving image can be compressed and encoded with an equivalent image code amount. it can.

  Next, operations of the camera 106, the camera 107, and the synchronization signal generator 108 will be described with reference to FIG. Reference numeral 501 denotes an image signal vertical readout timing signal from the image sensor 101 in the camera 106, 502 denotes an image signal vertical readout timing signal from the image sensor in the camera 107, and 503 denotes a vertical synchronization alignment reference signal output from the synchronization signal generator 108. is there. As shown in FIG. 5, it is assumed that the image signal vertical readout timing signal 501 and the image signal vertical readout timing signal 502 are shifted from the image signal vertical readout timing in units of frames.

  As shown in FIG. 5, according to the vertical synchronization alignment reference signal 503, the camera 106 and the camera 107 operate so that the respective image signal vertical readout timing signals are synchronized in units of frames by the respective driving units.

  By performing such an operation, the plurality of cameras 106 and 107 can output synchronized image signals from the respective cameras.

  As described above, according to the embodiment of the present invention, image data captured and compressed by a plurality of cameras can have an equivalent amount of image information at the same imaging time, and therefore compressed by an object recognition processing unit or the like. Even if the image data is demodulated and subjected to processing such as planar projection stereo method and correspondence of points and lines, image processing such as an object recognition function can be performed with high accuracy.

It is a block diagram which shows the structure of embodiment of the image data transmission system by this invention. It is a timing chart which shows the 1st method of synchronizing GOP change in the present invention. It is a timing chart which shows the 2nd method of synchronizing GOP switching in this invention. It is a timing chart which shows the 3rd method of synchronizing GOP switching in the present invention. 6 is a timing chart showing an operation of synchronizing the image signal vertical readout timing from the image sensor according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Image pick-up element, 102 ... Drive part, 103 ... Image signal processing part, 104 ... Image signal compression part, 105 ... Communication part, 106, 107 ... Camera, 108 ... Synchronization signal generation part, 109 ... Communication network, 110 ... Object Recognition processing unit 201: Image data compressed and encoded by camera 106, 202 ... Image data compressed and encoded by camera 107, 203 ... GOP synchronization reference signal output from synchronization signal generating unit 108, 301 ... Camera 106 image data compressed and encoded by 106, 302... Image data compressed and encoded by camera 107, 303... GOP synchronization reference signal output from synchronization signal generator 108, 401. Image data 402 ... Still image data compression-encoded by the camera 107 403 ... Synchronization signal generator 108 Output GOP synchronization alignment reference signal 404... Frame count number counted by camera 107 501. Image signal vertical readout timing signal from image sensor in camera 106 502. Image signal vertical readout from image sensor in camera 107 Timing signal, 503... Vertical synchronization alignment reference signal output from the synchronization signal generator 108.

Claims (7)

  An imaging unit that converts an optical signal imaged by the optical system into an electrical signal and outputs it as an image signal, a driving unit that drives the imaging unit, and an image process that performs image processing on the image signal output from the imaging unit Image signal processing means for outputting as data, image signal compression means for compressing and encoding the image data output from the image signal processing means and outputting as compression encoded image data, and the output from the image signal compression means A plurality of image data transmission devices each configured by communication means for transmitting compression-encoded image data to another device via a communication network; and synchronization signal generation means for generating a synchronization signal at a desired timing. An image data transmission system comprising: the image signal compression means of each of the plurality of image data transmission devices from the synchronization signal generation means Image data transmission system and performs compression coding to have the same GOP structure at the same time in accordance with the said synchronization signal.   2. The image data transmission system according to claim 1, wherein the synchronization signal generation means transmits the synchronization signal to the image signal compression means of each of the plurality of image data transmission devices via the communication network. Image data transmission system.   3. The image data transmission system according to claim 1, wherein each of the driving units of the plurality of image data transmission apparatuses is configured to each of the plurality of image data transmission apparatuses in accordance with the synchronization signal from the synchronization signal generation unit. An image data transmission system that outputs image signals at the same imaging timing from the imaging means.   An imaging unit that converts an optical signal imaged by the optical system into an electrical signal and outputs it as an image signal, a driving unit that drives the imaging unit, and an image process that performs image processing on the image signal output from the imaging unit Image signal processing means for outputting as data, image signal compression means for compressing and encoding the image data output from the image signal processing means and outputting as compression encoded image data, and the output from the image signal compression means A plurality of image data transmission devices each configured by communication means for transmitting compression-encoded image data to another device via a communication network; and synchronization signal generation means for generating a synchronization signal at a desired timing. In the image data transmission system, the image signal compression unit of each of the plurality of image data transmission apparatuses has a GOP picture number n ( Image data transmission system and performs compression coding of the I picture at the same time in accordance with the said synchronization signal from and the synchronizing signal generating means in the GOP structure as a common multiple of the integer).   5. The image data transmission system according to claim 4, wherein the synchronization signal generation means transmits the synchronization signal to the image signal compression means of each of the plurality of image data transmission devices via the communication network. Image data transmission system.   6. The image data transmission system according to claim 4, wherein each of the plurality of image data transmission apparatuses includes a plurality of image data transmission apparatuses, each of the plurality of image data transmission apparatuses according to the synchronization signal from the synchronization signal generation unit. An image data system that outputs image signals at the same imaging timing from the imaging means. 7. The image data transmission system according to claim 1, wherein at least one of the plurality of image data transmission devices is compressed at the same time in accordance with a signal from the synchronization signal generating means. An image data transmission system characterized in that the means performs compression coding of still images, and the other image data transmission device performs compression coding of I pictures.

Images