JP3797634B2 - Image transmission device in surveillance system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monitoring system having monitoring means such as a monitoring camera that images a monitoring area, and more particularly to an image transmission apparatus in the monitoring system.
[0002]
[Prior art]
Conventionally, an image transmission apparatus in this type of surveillance system compares the current screen captured from the surveillance camera with the previous screen, which is the previous screen of the current screen, and the change of the current screen relative to the previous screen. Only the large part was detected and only that part was transmitted to the transmission line (see, for example, Japanese Patent Laid-Open Nos. 61-150484, 61-116488, and 64-73878) . A receiving-side device connected to the transmission path receives the transmitted data, copies it to a monitor TV, etc., and monitors it. According to this, since only the part where the change of the current screen with respect to the previous screen is large is transmitted, the transmission speed of the image can be substantially increased.
[0003]
[Problems to be solved by the invention]
However, in the above-described image transmission device, when comparing the current screen captured from the surveillance camera with the previous screen, all the parts on the current screen are compared with the previous screen, which requires a lot of comparison processing time. It was.
[0004]
Therefore, an object of the present invention is to provide an image transmission apparatus in a monitoring system that can shorten the comparison processing time.
[0005]
[Means for Solving the Problems]
According to the present invention, in an image transmission apparatus in a monitoring system having an imaging unit that images a monitoring area and outputs a plurality of continuous imaging screens each of which includes a plurality of blocks, the plurality of continuous imaging screens A current screen memory for storing the current screen as a current screen, a previous screen memory for storing a previous screen of the current screen among the plurality of consecutive imaging screens as a previous screen, and the current screen A plurality of blocks of the current screen connected to a corresponding block of the plurality of blocks of the previous screen according to a control signal and connected to the memory and the previous screen memory; And a comparator that outputs a comparison result signal representing the plurality of continuous imaging screens, and for a predetermined block of the plurality of blocks of each imaging screen, A comparison control unit that outputs the control signal so as to perform comparison by the comparator for each imaging screen, and a magnitude of a change between the blocks that is connected to the comparator and represented by the comparison result signal Memory controller that reads a corresponding block of the predetermined block of the plurality of blocks of the current screen from the current screen memory as a read block when the current value is larger than a predetermined threshold; A transmission unit configured to transmit the output block to a transmission line, and the comparison control unit is configured to provide the comparator for each of the remaining blocks of the plurality of imaging screens at least every other imaging screen. The control signal is output so as to make a comparison according to the above, and the memory control unit generates a large change between the two blocks represented by the comparison result signal. When the value is larger than the predetermined threshold value, the corresponding block of the remaining blocks of the plurality of blocks of the current screen is read as the read block from the current screen memory. An image transmission apparatus in a monitoring system characterized by the above can be obtained.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0008]
Referring to FIG. 1, an image transmission apparatus according to an embodiment of the present invention is applied to a surveillance system having a surveillance camera 1.
[0009]
For example, the monitoring camera 1 functions as an imaging unit that captures an image of a monitoring area as illustrated in FIG. 2 and outputs a plurality of continuous imaging screens. As shown in FIG. 3, each imaging screen is composed of a plurality of blocks (8 × 8 blocks a11 to a18,..., A81 to a88 in the illustrated example). In the monitoring area of FIG. 2, the most important monitoring parts are doors and windows. Among the plurality of blocks a11 to a18,..., A81 to a88 in FIG. 3, the portions corresponding to the doors and windows in FIG. 2 are blocks a31 to a35, a41 and a42, a51 and a52.
[0010]
In FIG. 1, an image transmission apparatus according to an embodiment of the present invention performs analog-to-digital conversion on a plurality of continuous imaging screens, which are outputs of the surveillance camera 1, and outputs a plurality of digitized continuous imaging screens A. / D converter 2 is provided.
[0011]
The current screen memory 3 is directly connected to the A / D converter 2 and stores the current screen among a plurality of digitized continuous imaging screens as the current screen.
[0012]
The previous screen memory 5 is connected to the A / D converter 2 via a delay element 4 having a delay time for one screen, and is one of the current screens among a plurality of digitized continuous imaging screens. The previous screen is stored as the previous screen.
[0013]
The comparator 6 is connected to the current screen memory 3 and the previous screen memory 5 and compares each of the plurality of blocks on the current screen with the corresponding block of the plurality of blocks on the previous screen in accordance with the control signal 7. A comparison result signal representing the magnitude of the change is output.
[0014]
The comparison control unit 8 is connected to the A / D converter 2 and receives a plurality of digitized continuous imaging screens. A predetermined block of the plurality of blocks of each imaging screen is determined for each imaging screen. A control signal 7 is output so that the comparison by the comparator 6 is performed. The predetermined blocks are blocks a31 to a35, a41, a42, a51, and a52 that constitute portions corresponding to the doors and windows in FIG. 2 among the plurality of blocks a11 to a18,. It is.
[0015]
The memory control unit 9 is connected to the comparator 6 and, when the magnitude of change between both blocks represented by the comparison result signal is larger than a predetermined threshold value, from the current screen memory 3 a plurality of current screens. A block corresponding to the predetermined block is read as a read block.
[0016]
The comparison control unit 8 outputs a control signal 7 so that the remaining blocks among the plurality of blocks of each imaging screen are compared by the comparator 6 at least every other imaging screen.
[0017]
In this case, when the magnitude of the change between the two blocks represented by the comparison result signal is larger than the predetermined threshold, the memory control unit 9 reads from the current screen memory 3 among the plurality of blocks on the current screen. The corresponding block of the remaining block is read as the read block.
[0018]
The transmission unit 10 transmits the read block to the transmission path 11.
[0019]
As described above, the comparison operation by the comparator 6 is performed for each imaging screen with respect to the predetermined block corresponding to the most important monitoring part such as a door or a window, and the monitoring part having a relatively low importance. For the remaining blocks corresponding to the above, the comparison operation by the comparator 6 is performed at least every other imaging screen. At this time, also in the remaining blocks described above, for example, the block corresponding to the wall of the monitoring area is monitored more frequently than the block corresponding to the floor of the monitoring area by the comparator 6. The frequency of the comparison operation by the comparator 6 can be changed according to the importance.
[0020]
【The invention's effect】
As described above, according to the present invention, the comparison operation of the comparator that compares the current screen with the previous screen is performed for each of the above-described predetermined blocks corresponding to the most important monitoring parts such as doors and windows. Since the above-mentioned remaining blocks corresponding to the monitoring part having a relatively low importance are caused to perform comparison operation by the comparator every other imaging screen, the comparison processing time is reduced. There is an effect that it can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram of an image transmission device in a monitoring system according to an embodiment of the present invention.
FIG. 2 is a diagram showing a monitoring area monitored by the image monitoring camera in FIG. 1;
3 is a diagram showing an imaging screen imaged by the image monitoring camera in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Surveillance camera 2 A / D converter 3 Current screen memory 4 Delay element 5 Previous screen memory 6 Comparator 7 Control signal 8 Comparison control part 9 Memory control part 10 Transmission part 11 Transmission path

Claims (1)

In an image transmission apparatus in a monitoring system that has an imaging unit that images a monitoring area and outputs a plurality of continuous imaging screens each of which includes a plurality of blocks.
A current screen memory for storing a current screen of the plurality of continuous imaging screens as a current screen;
A previous screen memory for storing a previous screen of the current screen among the plurality of continuous imaging screens as a previous screen;
Connected to the current screen memory and the previous screen memory, and according to a control signal, each of the plurality of blocks of the current screen is compared with a corresponding block of the plurality of blocks of the previous screen, and changes between both blocks A comparator that outputs a comparison result signal representing the magnitude of
A comparison that receives the plurality of consecutive imaging screens and outputs the control signal for a predetermined block of the plurality of blocks of each imaging screen so that the comparison is performed by the comparator for each imaging screen. A control unit;
When the magnitude of the change between the two blocks, which is connected to the comparator and represented by the comparison result signal, is larger than a predetermined threshold value, the current screen memory is selected from the plurality of blocks of the current screen. A memory control unit that reads a corresponding block of the predetermined block as a read block;
A transmission unit that transmits the read block to a transmission path;
The comparison control unit outputs the control signal so that the remaining blocks of the plurality of blocks of each imaging screen are compared by the comparator every other imaging screen. ,
The memory control unit, when the magnitude of change between the two blocks represented by the comparison result signal is larger than the predetermined threshold value, from the current screen memory to the blocks of the current screen. An image transmission apparatus in a monitoring system, wherein the corresponding block of the remaining block is read as the read block.

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