JPS6357840B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention monitors the flow of vehicle traffic by automatically processing patterns captured by a television camera without human intervention, detects traffic stagnation, etc., and issues an alarm. This invention relates to a traffic jam detection device using video image signals.

Traditional methods for detecting traffic jams in tunnels, etc. have been to use a combination of multiple traffic measuring instruments of various methods, or to install multiple optical vehicle detectors. All of these methods lacked reliability due to accumulation of measurement errors, and in the end, people had no choice but to constantly monitor television images and make decisions.

The present invention has been made in view of the above conventional problems, and embodiments of the present invention will be described below with reference to the accompanying drawings. Figure 1 shows an example of camera arrangement when a large number of television cameras 1 are arranged in a road tunnel to detect traffic congestion.The optical axis of camera 1 is almost parallel to the traffic flow on a horizontal plane. It is arranged like this.

FIG. 2 shows a system diagram of a traffic jam detection device according to an embodiment of the present invention, and its operating principle will be explained with reference to the signal processing pattern diagram of FIG. 3. In Figure 2, 1 is a television camera arranged in the state shown in Figure 1, 2 is a multiplexer that sequentially transmits video signals taken out from multiple television cameras to the next stage, and 3 is an electrical masking operation. This is a fault area removal circuit which removes from the screen an area which is arbitrarily set in advance and is unnecessary or which may cause an obstruction.The output of this circuit is as shown by A in FIG. 3b. 3b is the removed portion, and FIG. 3a is the pattern shown by the original video signal. Needless to say, the area to be removed is a part where a vehicle to be monitored cannot exist, and a part which is unnecessary or harmful as a signal, such as lighting equipment or a sign light. 4 is a video signal horizontal integration circuit that compresses a two-dimensional video signal by integrating it on the horizontal scanning line axis and converts it into a one-dimensional luminance distribution on the vertical axis. Through the processing of this circuit, The pattern shown is converted into a one-dimensional distribution shown in Figure 3c. Here V indicates the vertical coordinate,
B indicates the average brightness on the coordinates. The waveform C in Figure 3c shows undulations, which is similar to Figure 3b.
This was caused by the vehicle shown in the figure. This undulation indicates the presence of a vehicle, and its movement on the V axis indicates movement of the vehicle. Therefore, it is possible to know the number of vehicles present and their running speed, and from both, it is possible to know the traffic situation, such as the traffic volume. Needless to say, the figure is a typical example, and in reality, it goes without saying that very complex waveforms will be processed. 5 is an analog-to-digital converter (first analog-to-digital converter) that digitally displays the distribution shown by C in FIG.
It is stored in 6. 7 compares and analyzes the contents of the storage device 6, which is updated at appropriate intervals, with the current situation, calculates the moving speed of the vehicle, etc. from the change in distribution and the speed of change,
This is an analysis device (first analysis device) that warns of traffic congestion.

Reference numeral 8 in FIG. 2 is a control device for synchronizing the entire system, sequentially processing signals from a large number of cameras 1, and assisting the analysis device 7 in comprehensive judgment.

FIG. 4 shows the main part of another embodiment of the present invention, and in the figure, 9 is the multiplexer 2 of FIG.
This is the output of 10 is a sampling circuit that extracts and separates the signals of several small areas set in advance from the pattern; if there are four small areas shown in Fig. 5, the output will be four circuits. Become. Although FIG. 5 shows an example in which small areas A to D are set in a television pattern, their number, size, shape, and position are arbitrary. Reference numeral 11 denotes an integration circuit that integrates the video signal for each frame and obtains the average brightness of each small area, and these outputs are then sent to a multiplexer 12, an analog-to-digital converter (second analog-to-digital converter) 13, and By the combination of the demultiplexer 14, the digital display is apparently done in parallel, and each frame is stored in the storage device (second storage device) 15 to show the current pattern. The contents of the storage device 15 are further transferred one after another to the storage device (third storage device) 16, and the contents of the storage device 16 always indicate the past pattern. 17 is an analysis device (second analysis device)
The two memory contents are compared, and based on the changes, it is possible to estimate the vehicle's entry into and exit from the small area, as well as the vehicle's presence time within the small area.
The system will detect traffic disruptions, slowdowns, etc., determine if there is a traffic jam, and issue an alert. The analysis device is configured by a general-purpose digital computer or the like. Next, the operation of the embodiment shown in FIG. 2 will be explained.

In the waveform shown in FIG. 3c, the waveform that protrudes to the right is caused by the presence of a vehicle. The analog/digital converter 5 to which this waveform is input compares the signal with a predetermined value for each horizontal scanning line of the waveform and digitizes it as "0" or "1". As a result, the output signal of the analog-to-digital converter 5 becomes, for example, "0001110-00" and is stored in the storage device 6. The image taken by the television camera 1 after a predetermined time is similarly subjected to signal processing, and the output signal of the analog-to-digital converter 5 becomes, for example, "0111000-00" and is input to the analysis device 7. The analysis device 7 also includes a storage device 6.
Digital signal “0001110~00” stored in
is also input. The analysis device 7 compares the output signal from the analog-to-digital converter 5 and the output signal from the storage device 6 to calculate the vehicle speed.

That is, for example, in the case of the above digital signal,
It is detected that the signal change on the horizontal scanning line indicating that the vehicle has moved during a predetermined time is two horizontal scanning lines, and the distance on the road corresponding to these two horizontal scanning lines is stored in advance in the analysis device 7. Then, convert two horizontal scanning lines into distance. Furthermore, the vehicle speed is calculated by dividing the converted distance by the predetermined time. If this vehicle speed is lower than a predetermined speed stored in advance, it is determined that the vehicle is stuck in a traffic jam and a warning signal is output.

Next, the example shown in FIG. 4 will be explained.

For example, the average brightness within one small area is the brightness of the road surface if there are no vehicles within that area, but when a car passes through this area, the brightness fluctuates up and down. By counting this variation, the number of passing vehicles can be determined. It is also possible to estimate the traveling speed from the time difference between fluctuations in two adjacent small areas. The purpose of providing a plurality of small areas is to more reliably capture vehicles and reduce counting errors.

An approximation formula derived from statistics based on actual measurements is used as the correlation function for calculating the traveling speed from the number of passing vehicles.

The reliability can be improved by using the two devices described above in combination as shown in FIG. That is, in the embodiment shown in FIG. 6, the output signals of both the analysis devices 7 and 17 are combined in the judgment circuit 18 to judge the traffic situation. The contents of the storage device 6 in FIG. 2 and the storage device 16 in FIG. It goes without saying that this method is effective in eliminating functional disorders caused by changes in sensitivity, etc.

As is clear from the above description, according to the present invention, compared to the method in which a person directly monitors the video pattern,
It has the following advantages: firstly, it saves labor, and secondly, there are no errors or non-monitoring periods that are common in human monitoring.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of the arrangement of television cameras of a traffic jam detection device according to an embodiment of the present invention, FIG. 2 is a system diagram of the same, FIG. 3 is a pattern diagram of the signal processing, and FIG. FIG. 5 is a system diagram showing a main part of another embodiment of the present invention, FIG. 5 is a diagram showing an example of sampling from the same pattern, and FIG. 6 is a system diagram according to the same embodiment of the present invention. 1...TV camera, 2, 12...Multiplexer, 3...Fault area removal circuit, 4...Video signal horizontal integration circuit, 5, 13...Analog-digital converter, 6, 15, 16...Storage device ,7,1
7... Analysis device, 8... Control device, 10... Sampling circuit, 11... Integrating circuit, 14... Demultiplexer, 18... Judgment circuit.

Claims (1)

[Scope of Claims] 1. A television camera that photographs the road, an obstruction area removal circuit that performs a mask operation to remove unnecessary parts from the pattern photographed by the television camera, and an obstruction area removal circuit that performs a mask operation to remove unnecessary parts from the pattern photographed by the television camera. a video signal horizontal integration circuit that integrates the two-dimensional luminance signal in the effective part of the pattern onto a horizontal scanning line and converts it into a one-dimensional luminance signal on the vertical axis; The first analog signal converts the original luminance signal into a digital signal.
a digital converter; a first storage device that stores the digital signal that is the output of the first analog-to-digital converter and updates the stored digital signal at predetermined intervals; A traffic congestion detection device comprising: a first analysis device that determines the traffic situation on the road by comparing and analyzing the output and the output of the first storage device. 2. A television camera that photographs the road, a fault area removal circuit that performs a mask operation to remove unnecessary parts from the pattern photographed by the television camera, and a valid part of the pattern left by this fault area removal circuit. A video signal horizontal integration circuit that divides the two-dimensional luminance signal into a one-dimensional luminance signal on the vertical axis by dividing it into a one-dimensional luminance signal on the vertical axis, and digitally converts the one-dimensional luminance signal obtained by this video signal integration circuit. a first analog-digital converter that converts the digital signal into a signal; a first storage device that stores the digital signal that is the output of the first analog-digital converter and updates the stored digital signal at predetermined intervals; a first analysis device that determines the traffic situation on the road by comparing and analyzing the output of the first analog-to-digital converter and the output of the first storage device; a sampling circuit that extracts a signal in a small area; an integrating circuit that obtains an average luminance from the signal in the small area extracted by the sampling circuit;
A second analog-to-digital converter converts the output signal of the integrating circuit into a digital signal, and the digital signal output from the second analog-to-digital converter is updated and stored each time it is input. a second storage device that outputs the digital signal output from the second storage device; a third storage device that updates and stores the digital signal output from the second storage device; and an output of the second storage device. a second analysis device that determines the traffic situation on the road by comparing and analyzing the output of the third storage device; and a second analysis device that determines the traffic situation on the road by comparing and analyzing the output of the third storage device; A traffic congestion detection device comprising: a judgment circuit for judging traffic conditions;