JPH1042276A - Transmission method in image monitoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission method in an image monitoring system capable of eliminating the need of a comparator circuit for comparing image data, processing time and the extraction processing of the change part of images and substantially reducing a transmission data amount compared to the case of transmitting all the image data fetched from a monitoring camera every time. SOLUTION: A transmission part 10 inputs the image data from the camera to an A/D converter 1 and a synchronizing separator circuit 2, digitally converts them and separates synchronizing signals. By a control circuit 6, a frame memory controller 3 writes the image data to a two-dimensional frame memory 4. Updated image data are compressed in an image data compression part 5 and sent through an image data transmission part 7 to a transmission line 9. A reception part 20 inputs the image data from an image data reception part 11 to an image data expansion part 12 and the control circuit 13, expands the image data, controls the frame memory controller 14 and writes the image data to the two-dimensional frame memory 15. The updated image data are converted in a D/A converter 16 and outputted to a monitor and a synchronizing signal generation circuit 17 generates the synchronizing signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a transmission method in an image monitoring system including a transmission unit and a reception unit used as a security system.

[0002]

2. Description of the Related Art Conventionally, image data fetched from a surveillance camera is compared with reference image data as previous image data to extract and transmit only a changed portion of the image.

[0003]

However, in a conventional transmission method in an image monitoring system including a transmitting unit and a receiving unit, the image data captured from the monitoring camera is compared with the reference image data to determine only the changed part of the image. Since the extraction is performed, there is a problem that a comparison circuit for comparing image data, a processing time, and a processing time for extracting a changed part of the image are required.

The present invention has been made in view of the above points, and does not require a comparison circuit for comparing image data and a processing time, and does not require a process of extracting a changed portion of an image.
Moreover, it is an object of the present invention to provide a transmission method in an image monitoring system capable of greatly reducing the amount of transmission data as compared with transmitting every time image data taken from a monitoring camera every time.

[0005]

On the transmitting side, image data taken in from a surveillance camera is A / D converted and written into a two-dimensional frame memory. This writing is performed in a state where the image data is divided into several blocks under the control of the control circuit and the frame controller, and the image data in the two-dimensional frame memory is sequentially updated. From the two-dimensional frame memory, only the designated block designated as an important monitoring area is read. Other blocks are included when the image data of all blocks is read out fewer times than the designated block. The read image data is compressed and transmitted.

On the receiving side, image data transmitted from the transmitting side is written in a two-dimensional frame memory under the control of a control circuit and a frame controller. By this writing, the image data in the two-dimensional frame memory is sequentially updated. The image data to be written to the two-dimensional frame memory is both the designated block and all blocks, and the number of all blocks is smaller than the number of designated blocks. The image data from the two-dimensional frame memory is D / A converted and output to a monitor. This eliminates the need for a comparison circuit for comparing image data and processing time, and eliminates the need to extract a changed portion of the image. In addition, the amount of transmitted data is smaller than when transmitting all of the image data captured from the surveillance camera every time. Yes.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A transmission method in an image monitoring system according to the present invention is a transmission method in an image monitoring system including a transmission unit and a reception unit, wherein the transmission unit performs A / D conversion on image data captured from a monitoring camera. Convert and A / D
The converted image data is divided into a plurality of blocks and written into the two-dimensional frame memory, and the image data in the two-dimensional frame memory is sequentially updated by writing, and the image data of the designated block designated as an important monitoring area is written in the two-dimensional frame memory. And reads and transmits the image data of all blocks from the two-dimensional frame memory at a smaller number of times than the reading of the image data of the designated block. At the receiving side, the image data transmitted from the transmitting unit is read. Is written in the two-dimensional frame memory, the image data in the two-dimensional frame memory is sequentially updated by the writing, the image data read from the two-dimensional frame memory is D / A converted, and the D / A converted image data is output to the monitor. It has special features.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating an outline of a transmission unit and a reception unit of an image monitoring system according to an embodiment of the present invention.
The transmission unit 10 of the image monitoring system inputs image data from the monitoring camera to the A / D converter 1 and the synchronization separation circuit 2. The A / D converter 1 converts image data from the surveillance camera into digital data. The synchronization separation circuit 2 separates the horizontal synchronization signal and the vertical synchronization signal from the image data and outputs them to the frame memory controller 3. The frame memory controller 3 converts the digitally converted image data into a two-dimensional frame memory 4 based on these synchronization signals.
Write to.

In this case, the frame memory controller 3
Divides the image data converted into digital data under the control of the control circuit 6 into a plurality of blocks and writes the divided blocks into the two-dimensional frame memory 4. By this writing, the image data in the two-dimensional frame memory 4 is sequentially updated. The two-dimensional frame memory 4 outputs the image data of the designated block to the image data compression unit 5, and outputs the image data of all the blocks to the image data compression unit 5 less times than the designated block. The image data compression unit 5 compresses the image data of the designated block or the image data of all blocks according to the control signal from the control circuit 6 and outputs the compressed image data to the image data transmission unit 7. The image data transmission unit 7 transmits the compressed image data and marker codes such as block position information to the image monitoring system reception unit via the transmission line 9.

[0010] In the receiving section 20 of the image monitoring system, the image data transmitted from the transmitting section 10 of the image monitoring system via the transmission line 9 is received by the image data receiving section 11. The received image data is input to the image data decompression unit 12 and the control circuit 13. The image data expansion unit 12 expands the input compressed image data. The control circuit 13 controls the frame memory controller 14 to write the image data expanded to the position of the designated block or the image data of all the blocks to the two-dimensional frame memory 15 according to the marker code information such as the position information of the block. .

By this writing, the designated block portion of the image data of the two-dimensional frame memory 15 is rewritten. However, the image data of all blocks is rewritten less times than the rewriting of the designated block portion. The frame memory controller 14 reads out image data from the two-dimensional frame memory 15 according to the synchronization signal from the synchronization signal generation circuit 17. The read image data is converted into analog image data by the D / A converter 16 and output to a monitor. The synchronization signal generation circuit 17 supplies a synchronization signal to the monitor and a timing signal to the frame memory controller 14.

FIG. 2 is a diagram of a monitoring image for explaining a monitoring target in the embodiment of the present invention. In the figure, 2
Reference numeral 5 denotes an image of the image monitoring system in which the door 21 and the window 22 are monitored.

FIG. 3 is a diagram in which a monitoring image is divided into a plurality of blocks for explaining a monitoring target in the embodiment of the present invention. Those denoted by the same reference numerals as those in FIG. 2 indicate the same elements. In this example, the image 25 is composed of a horizontal 8 vertical 6
Are divided into a total of 48 blocks. The horizontal is eight blocks M0 to M7, and the vertical is six blocks N0 to N5. If the important monitoring area is door 21, M1N1, M1N2,
The four blocks M2N1 and M2N2 are designated blocks. At this time, the transmission data amount is 4/48 of the total data.

If the important monitoring area is the window 22,
M4N1, M4N2, M5N1, M5N2, M6N1,
The six blocks of M6N2 are designated blocks. At this time, the transmission data amount is only 6/48 of the total data. Furthermore, if the important monitoring area is the door 21 and the window 22, M1N1,
M1N2, M2N1, M2N2, M4N1, M4N2
The ten blocks M5N1, M5N2, M6N1, and M6N2 are designated blocks. The amount of transmission data at this time is only 10/48 of the total data.

[0015]

As described above, according to the transmission method in the image monitoring system of the present invention, in the transmission method in the image monitoring system including the transmission unit and the reception unit, the transmission unit transmits the image data captured from the monitoring camera. A / D
The converted and A / D converted image data is divided into a plurality of blocks and written into the two-dimensional frame memory, and the image data in the two-dimensional frame memory is sequentially updated by writing,
The image data of the designated block designated as an important monitoring area is read out from the two-dimensional frame memory and transmitted, and the image data of all blocks is read out from the two-dimensional frame memory and transmitted with a smaller number of times than the image data of the designated block is read out. On the receiving side, the image data transmitted from the transmitting unit is written into the two-dimensional frame memory, the image data in the two-dimensional frame memory is sequentially updated by the writing, and the image data read from the two-dimensional frame memory is written into the two-dimensional frame memory. Since the A / A converted and D / A converted image data are output to the monitor, a comparison circuit for comparing the image data and a processing time are not required, and a process of extracting a changed portion of the image is not required. The amount of transmitted data can be smaller than transmitting all of the monitoring image data every time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a transmission unit and a reception unit of an image monitoring system according to an embodiment of the present invention.

FIG. 2 is a diagram of a monitoring image for explaining a monitoring target in the embodiment of the present invention.

FIG. 3 is a diagram in which a monitoring image is divided into a plurality of blocks in order to explain a monitoring target in the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 A / D converter 2 Sync separation circuit 3 Frame memory controller 4 2D frame memory 5 Image data compression unit 6 Control circuit 7 Image data transmission unit 9 Transmission line 10 Transmission unit of image monitoring system 11 Image data reception unit 12 Image data Decompression unit 13 Control unit 14 Frame memory controller 15 Synchronization signal generation circuit 16 D / A converter 20 Reception unit of image monitoring system 21 Door 22 Window 25 Image

Claims (1)

[Claims] 1. A transmission method in an image monitoring system including a transmission unit and a reception unit, wherein the transmission unit A / D converts image data captured from a surveillance camera, and converts the A / D converted image data into a plurality of data. Dividing into blocks, writing to the two-dimensional frame memory, sequentially updating the image data of the two-dimensional frame memory by writing, reading and transmitting the image data of the designated block designated as an important monitoring area from the two-dimensional frame memory, The image data of all blocks is read out from the two-dimensional frame memory and transmitted at a smaller number of times than the readout of the image data of the designated block, and the receiving side writes the image data transmitted from the transmitting unit to the two-dimensional frame memory. The image data in the two-dimensional frame memory is sequentially updated by writing The image data read from the frame memory D /
A transmission method in an image monitoring system, wherein A-converted and D / A-converted image data are output to a monitor.