JP2004146940A - Network system for transmitting video - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network system for transmitting a video with high quality by a small amount of data. <P>SOLUTION: The network system includes: a supervisory network camera apparatus 10 having a means for obtaining pixel state data denoting a temporal change in data of each pixel of a photographed picture, separating a moving picture part and a still picture part of the photographed picture by using the pixel state data, compressing data of the moving picture part, and transmitting the compressed data of the moving picture part and the pixel state data to a network 5; and a supervisory network display apparatus 17 for decoding the photographed picture from the compressed data of the moving picture part and the pixel state data received from the network 5. The system easily separates the still picture and the moving picture at a high speed by using the pixel state data with a small information amount and can compress the image data with high image quality at a high compensation rate and reproduce the data. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a video transmission network system in which a video transmission device and a video reception device are connected to a network, and more particularly, to a video transmission network for compressing video data captured by a camera while maintaining high image quality and transmitting the video data to the network. About the system.
[0002]
[Prior art]
For example, when transmitting surveillance image data captured by a monitoring camera device using a network, the captured image is transmitted at a reduced transfer rate on the network while maintaining the image quality required for monitoring. The data size is reduced uniformly by general image compression encoding such as JPEG or MPEG.
[0003]
However, if the image data is compressed at a standard compression ratio of JPEG or MPEG after capturing the captured image data into the camera, there is a problem that the image data size cannot be reduced so much when there are many moving images.
[0004]
For this reason, conventionally, as described in, for example, Japanese Patent Application Laid-Open No. 2001-128180 (Patent Document 1), first, background data is compressed and transmitted, and then a moving image having a smaller image size is compressed. The decoding device side decodes the moving image data after decoding the background image data, and superimposes the moving image on the background image, so that the observer apparently has a large image size of the moving image. The image quality is felt good, and the amount of data to be transmitted is reduced.
[0005]
[Patent Document 1]
JP 2001-128180 A
[Problems to be solved by the invention]
However, according to the above-described conventional technology, the image quality of a moving image is not actually good, and the observer simply feels that the image quality is good. For a general monitoring system, this conventional technique is convenient in reducing the transmission load, but when the importance of the monitoring target is high, transmission of a high-quality moving image is actually required.
[0007]
An object of the present invention is to provide a video transmission network system capable of transmitting high-quality image data to a network with high compression and a small data amount.
[0008]
[Means for Solving the Problems]
A video transmission network system according to the present invention that achieves the above object has pixel state data detecting means for obtaining pixel state data indicating a time change of data of each pixel of a captured image. And a video transmitting device that separates the moving image portion using the pixel state data and compresses the moving image portion to transmit the compressed data of the moving image portion and the pixel state data to a network, and the moving image portion received from the network. A video receiving device for restoring the captured image from the compressed data and the pixel state data and displaying the restored image on a display.
[0009]
With this configuration, it is possible to reduce the amount of transmission data by compressing only the moving image portion. Quality video can be played. In addition, since the pixel state data is used, image data can be compression-encoded at a high compression rate in real time without using a frame memory or the like. Since there is no need to separate the moving image portion and the still image portion, high-speed image processing can be performed with a low-cost circuit.
[0010]
Preferably, in the above, the pixel state data detecting means is incorporated in an image sensor included in the video transmitting device. With this configuration, the processing load for obtaining the pixel state data in the video transmission device is reduced.
[0011]
More preferably, in the above, the pixel state data detecting means obtains a difference between the charge amounts read from the photosensitive portion of the image sensor to two vertical transfer paths at a time interval. And With this configuration, pixel state data can be obtained at high speed by hardware processing, and it becomes easy to transmit pixel state data to a network prior to transmission of image data.
[0012]
More preferably, in the above, the pixel state data is transmitted to the network prior to the compressed data. With this configuration, it is possible to perform real-time processing using pixel state data, which has a much smaller amount of information than compressed data of image data and is capable of high-speed transfer, and predicts a pixel state before transfer of image data in various processes.
[0013]
More preferably, the video receiving device is characterized by processing the display data of the captured image to be displayed on the display using the received pixel state data, the processing is the processing of the display data It is characterized by at least one of an afterimage prevention process, a brightness reduction process other than a moving image portion, a contrast reduction process other than a moving image portion, a burn-in prevention process using a still image portion, and a moving image portion enhancement process. With this configuration, it is possible to display an easy-to-view image, to compensate for a delay in responsiveness, and to extend the life of the display.
[0014]
The above object is also achieved by a video transmitting device or a video receiving device constituting the video transmission network system according to any of the above. As a result, the amount of transmission data can be reduced by compressing only the moving image portion, and the video receiving apparatus that receives the compressed data and the pixel state data originally having a small data amount can perform high-quality decoding on the compressed data and the pixel state data. Video can be played. In addition, since the pixel state data is used, image data can be compression-encoded at a high compression rate in real time without using a frame memory or the like. Since there is no need to separate the moving image portion and the still image portion, high-speed image processing can be performed with a low-cost circuit.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a configuration diagram of a video transmission network system according to an embodiment of the present invention. The network system for video transmission includes a monitoring network camera device 10 as one of video transmission devices connected to the network 5 and a monitoring network display device 17 as one of video reception devices.
[0017]
The surveillance network camera device 10 includes an imaging element unit 11 that converts light from an imaging target into an electric signal, an image data conversion unit 12 that converts pixel data output from the imaging element unit 11 into image data, The image compression / encoding unit 13 which compresses and encodes image data output from the conversion unit 12 and transmits / receives data to / from another device connected to the network 5 on the network 5 to perform the image compression / encoding. A network unit 14 for transmitting the image data compressed and encoded by the unit 13 to the network 5, a memory unit 15 for temporarily storing the image data, an image sensor unit 11, an image data conversion unit 12, an image compression unit The control unit 16 includes an encoding unit 13, a network unit 14, and a control unit 16 that controls the memory unit 15.
[0018]
The imaging element unit 11 according to the present embodiment outputs pixel state data, which will be described later, in addition to the above-described pixel data that is a source of a monitoring image. The network unit 14 outputs compressed image data generated from the pixel data. , The pixel state data is output to the network 5.
[0019]
The monitoring network display device 17 is connected to the network 5, transmits and receives data to and from other devices on the network 5, and receives the image data and the pixel state data sent from the monitoring network camera device 10. A network unit 18 for decoding, image decoding and conversion unit 19 for decoding image data encoded in JPEG or MPEG and transmitted on the network 5, and image data transmitted on the network 5 with only moving images. A video data creation unit 20 for restoring a complete video signal using pixel state data transmitted at high speed prior to the image data, a display unit 21 for displaying the video signal, and temporarily storing the image data Memory unit 22 for performing these operations, network unit 18, image decoding conversion unit 19, video data creation unit 0, the display section 21, and a control unit 23 for controlling the memory unit 22.
[0020]
FIG. 2 is a functional configuration diagram of the imaging element unit 11 shown in FIG. In the imaging device section 11 composed of a CCD (charge coupled device) or the like, a large number of photosensitive units (only one row is shown) 25 arranged vertically and horizontally to accumulate electric charges according to the amount of received light, and the photosensitive units 25 are accumulated. A first vertical transfer path 26 for reading out charges (pixel data) and transferring the read data in the vertical direction, and a first horizontal transfer path for transferring the pixel data transferred by the first vertical transfer path 26 in the horizontal direction and outputting from the image sensor unit 11 And a transfer path 27. The configuration up to this point is the same as the configuration of a normal CCD.
[0021]
The imaging element unit 11 according to the present embodiment further includes a second vertical transfer path 28 that is juxtaposed on the first vertical transfer path 26 to read out the accumulated charges of the photosensitive unit 25, and a first vertical transfer path 28 juxtaposed on the second vertical transfer path 28. A third vertical transfer path 29 for comparing each charge amount read out to the vertical transfer path 26 and the second vertical transfer path 28 for each pixel, obtaining difference data as pixel state data, and transferring the data in the vertical direction; A second horizontal transfer path 30 that transfers the pixel state data transferred by the transfer path 29 in the horizontal direction and outputs the data from the image sensor unit 11.
[0022]
Next, the operation of the monitoring network system having the above configuration will be described. FIG. 3 is a flowchart illustrating an operation procedure of the imaging element unit 11. The imaging element unit 11 receives an operation command from the control unit 16 and operates at a frequency that is at least twice the horizontal scanning frequency when outputting pixel data. Similarly, it operates at a vertical scanning frequency of twice or more.
[0023]
For example, when capturing 30 frames of video per second and outputting pixel data, first, the charge stored in the photosensitive section 25 is read out to the first vertical transfer path 26 (step S1), and after 1/60 second at the latest. This time, the charge stored in the photosensitive section 25 is read out to the second vertical transfer path 28 (step S2). Then, the charge amounts read to the first vertical transfer path 26 and the second vertical transfer path 28 are compared, and difference data is obtained for each pixel as pixel state data (step S3).
[0024]
Next, the pixel state data obtained as the difference data is stored in the third vertical transfer path 29 (step S4), and the third vertical transfer path 29 is driven at a high speed to transfer the pixel state data to the second horizontal transfer path 30. Transfer (step S5). Further, the first vertical transfer path 26 is driven to transfer the pixel data to the first horizontal transfer path 27 (Step S6).
[0025]
Then, the second horizontal transfer path 30 is driven at high speed to output pixel state data from the image sensor unit 11 (step S7), and the first horizontal transfer path 27 is driven to output pixel data from the image sensor unit 11 (step S7). Step S8). That is, in the present embodiment, the pixel state data is output from the imaging element unit 11 prior to the output of the pixel data. The charge read from the photosensitive section 25 to the second vertical transfer path 28 is discarded after the creation of the difference data.
[0026]
In this way, the pixel data output from the imaging element unit 11 is output to the image data conversion unit 12, where it is converted into the original horizontal frequency and vertical frequency as image data to become a video output signal.
[0027]
The pixel state data output from the imaging element unit 11 is difference data between the captured images in 1/60 seconds in the above example, and is data that causes a difference when the captured image moves or changes. This pixel state data is converted from one bit to several bits of small data as necessary, and is transferred to the control unit 16 at high speed. When discriminating between a moving image and a still image, the pixel state data is 1-bit data. When the data of the increase / decrease state of each pixel is included, the data is several bits.
[0028]
The image compression encoding unit 13 performs data compression such as JPEG or MPEG. At this time, based on a command from the control unit 16 that has identified a moving image portion and a still image portion from the pixel state data, the moving image portion and the still image portion are compressed. And compressing only the video part. Since the pixel state data can be transferred at a higher speed than the video output signal output from the image data converter 12 to the image compression encoder 13, the moving image portion and the still image portion can be separated in real time.
[0029]
As described above, in the present embodiment, since only the moving image portion in the captured image is cut out in real time and JPEG-compressed or MPEG-compressed, the data amount can be reduced as compared with the case where the entire captured image is data-compressed. It becomes.
[0030]
The network unit 14 transmits the video signal compressed and encoded by the image compression encoding unit 13 and other control data and pixel state data to the network 5. At this time, the pixel state data is transmitted prior to the video signal.
[0031]
The monitoring network display device 17 receives various data transmitted from the monitoring network camera device 10 by the network unit 18. The received video signal, that is, the encoded image data, is decoded by the image decoding conversion unit 19. Further, the video data creating unit 20 converts the image data (image data decoded by the image decoding conversion unit 19) transmitted on the network 5 only with the moving image into the pixel state data previously transmitted at high speed. To restore a complete video signal, and the display unit 21 displays this video signal. As a result, a high-quality monitoring video is displayed.
[0032]
When the monitoring image is displayed on the display unit 21 in this manner, the control unit 23 according to the present embodiment uses the pixel state data transmitted in advance to illuminate the pixels of the moving image portion in advance, Lights are turned off and the like, and after-images and blurs due to delays caused by lighting and turning off the pixels on the display unit 21 are reduced.
[0033]
Further, as shown in FIG. 4, the control unit 23 uses the pixel state data to separate the moving image portion 40 and the still image portion 41 in the monitoring video to reduce the contrast and brightness of the pixels of the still image portion 41. And display it. As a result, burn-in due to long-time display of the still image portion 41 is prevented.
[0034]
As described above, according to the present embodiment, the moving image portion in the captured image is separated from the still image portion using the pixel state data output from the imaging element portion 11 and data compression is performed only on the moving image portion. Since the data is transmitted together with the pixel state data, the data compression ratio is improved, the transmission load is reduced, and a high-quality monitoring video can be reproduced.
[0035]
In addition, since the pixel state data is transmitted prior to the image data, the display device uses the pixel state data to reduce afterimages on the display screen and easily prevent burn-in of a still image portion. Further, it is possible to add an excellent function such as emphasizing a moving image portion to a still image portion.
[0036]
In the above-described embodiment, the pixel state data is created by the image sensor unit. However, a difference between pixel data output from the image sensor unit may be used as pixel state data. Further, although the monitoring network system is configured by the monitoring network camera device and the monitoring network display device, the present invention is similarly applicable to other network devices.
[0037]
【The invention's effect】
According to the present invention, it is possible to construct a video transmission network system capable of compressing image data at a high data compression rate and transmitting high-quality images.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a video transmission network system according to an embodiment of the present invention; FIG. 2 is a functional configuration diagram of an imaging element unit mounted on a video transmission network camera device according to an embodiment of the present invention; FIG. 3 is a flowchart showing an operation procedure of the image sensor according to the embodiment of the present invention. FIG. 4 is an explanatory diagram of prevention of burn-in in the video transmission network display device according to the embodiment of the present invention.
Reference Signs List 10 surveillance network camera device 11 imaging device unit 12 image data conversion unit 13 image compression encoding unit 14, 18 network unit 15, 22 memory unit 16, 23 control unit 17 monitoring network display device 19 image decoding conversion unit 20 video Data creating unit 21 Display display unit 25 Photosensitive unit 26 First vertical transfer path 27 First horizontal transfer path 28 Second vertical transfer path 29 Third vertical transfer path 30 Second horizontal transfer path 40 Moving image part 41 Still image part

Claims (8)

Pixel state data detection means for obtaining pixel state data indicating a time change of data of each pixel of the captured image is provided.The moving image portion and the still image portion of the captured image are separated using the pixel state data, and the moving image portion is separated. A video transmitting device that compresses the data and transmits the compressed data of the moving image portion and the pixel state data to a network, and restores the captured image from the compressed data of the moving image portion and the pixel state data received from the network. A video transmission network system, comprising: a video receiving device for displaying on a display. 2. The video transmission network system according to claim 1, wherein said pixel state data detection means is built in an image pickup device of said video transmission device. 3. The pixel state data detecting unit according to claim 2, wherein the pixel state data detecting unit calculates a difference between the charge amounts read from the photosensitive unit of the image sensor to two vertical transfer paths at a time interval. Video transmission network system. 4. The video transmission network system according to claim 1, wherein the pixel state data is transmitted to a network prior to the compressed data. The video according to any one of claims 1 to 4, wherein the video receiving device processes display data of the captured image to be displayed on the display using the received pixel state data. Transmission network system. The processing is at least one of the afterimage prevention processing of the display data, the brightness reduction processing other than the moving image part, the contrast reduction processing other than the moving image part, the burn-in prevention processing by the still image part, and the enhancement processing of the moving image part. The video transmission network system according to claim 5, wherein: An image transmission device constituting the image transmission network system according to claim 1. A video receiving apparatus constituting the video transmission network system according to claim 1.

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