JPH09102097A - Traffic volume measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To count vehicles on a road without processing a screen image and eliminate the need for high-level image processing by setting a detection area in one lane on the road and sequentially measuring the total value of pixel density in the detection area. SOLUTION: When a measuring time T2 is set to a timer 48, an area lightness decision part 45 counts the total value of the pixel density in the detection area 20 at intervals of clocks T1 from the timer 48. Namely, the lightness in the area 20 is detected for every clock T1. Then a comparative decision part 47 compares the total value with the last pixel density stored in a memory 46 and stores it in the memory 46 after adding 1 to the count 49 when there is variation larger than a specific value or as it is when not. Then it is judged whether or not the measuring time T2 is elapsed and once the time T2 is elapsed, the value of the counter 49 is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traffic volume measuring apparatus, and more particularly to a traffic volume measuring apparatus which counts the number of vehicles traveling on a road using an ITV camera (industrial television camera) to measure the traffic volume. .

For example, when an attempt is made to measure the traffic volume by counting the number of vehicles on a one-way three-lane road across a median strip as shown in FIG. 1, an ITV camera is used in a conventional traffic volume measuring device. It counts by capturing the surface image within a predetermined range.

FIG. 6 is a diagram for explaining the operation of such a conventional traffic volume measuring apparatus. When counting the number of vehicles in this type of conventional traffic measuring device, an ITV camera captures a screen image in the range shown in frame 10 of FIG. 6A, for example, when the vehicle is not traveling at all. The image processing of the surface image of the same range and the surface image by comparing the brightness difference of each part is performed, and only the image of the vehicle within this frame 10 is extracted and extracted as shown in FIG. 6B. The number of vehicles is counted and output from the video.

[0004]

As described above, since the conventional traffic volume measuring apparatus of this type is configured to count the number of vehicles extracted by the image processing of the screen image, an error due to time or weather may occur. There is a problem in that it is likely to occur, requires advanced image processing, and cannot perform real-time processing.

That is, in the conventional apparatus, it is necessary to store, as a sample image to be compared, a surface image in the same range which is imaged in advance when the vehicle is not traveling at all.
For example, when the vehicle is not running at all in the early morning and when measuring the traffic volume, the time difference is usually large, and the background brightness itself changes due to this time difference, or the weather changes, Similarly, the brightness itself of the background often changes, and thus errors are likely to occur.

Further, there are problems that dedicated hardware and software for performing image processing of the surface image are required, the apparatus becomes expensive, and processing time for processing the surface image is required.

The present invention has been made to solve the above problems, and an object thereof is to provide a traffic volume measuring device capable of counting the number of vehicles on a road without performing image processing of a plane image. There is.

[0008]

A traffic volume measuring apparatus according to the present invention sets a detection area within one lane on a road, successively measures the total value of pixel densities in this detection area, and calculates the previous total. When there is a change of a predetermined value or more in comparison with the value, the number of vehicles on the road is counted by counting that one vehicle has passed in the lane.

When the road has a plurality of lanes, the detection areas are provided in the respective lanes, and the number of vehicles on the road is counted.

Further, the present invention is characterized in that the count value of the number of vehicles passing through the detection area within the measurement time is output as the traffic volume within a predetermined time.

Further, it is characterized in that the counter value of the number of vehicles passing through the detection area is output as a traffic volume within a predetermined range within the measurement time calculated from the traveling speed of the vehicle.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram for explaining the measurement principle of the traffic volume measuring device of the present invention, and 20 is a detection area.

The traffic volume measuring apparatus of the present invention does not process the surface image to count the number of vehicles, but travels by changing the brightness of the detection area of a size corresponding to each lane as shown in FIG. Count the number of vehicles.

That is, considering the lane in which the detection area 20 is set, a vehicle traveling in this lane always passes through the detection area 20, so that the brightness of the detection area 20 changes each time the vehicle passes. In this embodiment, the number of traveling vehicles is counted based on this change in brightness.

FIG. 3 is a diagram for explaining this. Considering a case where the front end and the rear end of the vehicle 30 pass points A to E, at the time when the tip approaches the point A, the detection area 20 is located. The brightness of does not change yet, but when it reaches point B, it starts to change, and the tip passes points C and D,
The brightness changes by a certain amount until the rear end passes the point D, and when the rear end passes the point D, the original brightness is restored.

Therefore, by setting a predetermined time in consideration of the traveling speed of the vehicle and counting the number of changes in the lightness in the detection area 20 within that time, the number of traveling vehicles can be counted.
It is possible to count the number of vehicles in a predetermined range of the lane.

Since the detection area 20 can be set to be relatively small, the brightness within the area is calculated by the total value of all pixel densities within the area, and when the total value changes by a predetermined value or more, the vehicle travels. The number of vehicles may be counted, and it is possible to count the number of vehicles with simple arithmetic processing without requiring special hardware or software.

In FIG. 2 and FIG. 3, the detection area 20 is set only in one lane for simplification of description, but it goes without saying that the detection area can be set in each lane.

FIG. 4 is a block diagram showing an embodiment of the device configuration of the traffic volume measuring device of the present invention. In FIG.
0 is traffic measuring device, 41 is ITV camera, 42 is TV
The image input unit 43 is a TV image display unit. Further, the traffic volume measuring device 40 includes a detection area setting unit 44, an area brightness measuring unit 45, a memory 46, a comparison and determination unit 47, a timer 48,
It is composed of a counter 49.

FIG. 5 is a flow chart for explaining the operation of this embodiment, and S1 to S7 show processing steps.

Next, the operation of this embodiment will be described with reference to FIGS. In step S1, the detection area setting unit 44 sets the detection area 20 in the TV image input from the TV image input unit 42.

The detection area 20 is set by, for example, applying a mask that electrically blocks signals from pixels other than the pixels for which the area is set.

Next, when a predetermined measurement time T2 is set in the timer 48, the total value of the pixel densities in the area is counted by the area lightness judgment unit 45 at the clock (T1) interval from the timer 48 in step S2. It

That is, the brightness within the area is detected at every clock (T1) based on the total value of the pixel densities within the area.

In the next step S3, the comparison / determination unit 47 compares with the previous total value of the pixel densities stored in the memory 46, it is determined whether or not there is a change of a predetermined value or more, and a change of the predetermined value or more is made. If there is, then 1 is added to the counter 49, and if there is no change equal to or more than a predetermined value, then it is stored as it is in the memory 46 as the total value of the previous pixel density in the next step S4.

In the next step S6, the measurement time (T2)
Is determined, and the value of the counter 49 is output when the time T2 has elapsed.

As described above, the detection area 2 is provided in each lane.
Generally, 0 is set to measure the traffic volume, and if the number of vehicles passing through in a predetermined time is to be measured,
Needless to say, the time may be set to the time T2, and if the traffic volume in the predetermined range is measured, the time T2 at which the vehicle in the range can be detected is set in consideration of the traveling speed of the vehicle.

[0028]

As described above, the traffic volume measuring apparatus of the present invention can count the number of vehicles on the road without performing the image processing of the surface image, thus eliminating the need for advanced image processing.

Further, since the brightness of only the area immediately before is compared and counted, there is an effect that there is no error due to time or weather and real-time measurement is possible.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a measurement target of a traffic volume measuring device of this type.

FIG. 2 is a diagram for explaining a measurement principle of the traffic volume measuring device of the present invention.

FIG. 3 is a diagram for explaining a detection area of the present invention.

FIG. 4 is a block diagram showing an embodiment of a traffic volume measuring device of the present invention.

FIG. 5 is a block diagram for explaining the operation of the traffic volume measuring device of the present invention.

FIG. 6 is a diagram for explaining a measurement principle of a conventional traffic volume measuring device.

[Explanation of symbols]

 20 Detection Area 30 Vehicle 40 Traffic Measurement Device 41 ITV Camera 42 TV Image Input Section 43 TV Image Display Section 44 Detection Area Setting Section 45 Area Lightness Measurement Section 46 Memory 47 Comparison Judgment Section 48 Timer 49 Counter

Claims (4)

[Claims] 1. A traffic volume measuring device which images the road with an ITV camera and counts the number of vehicles on the road based on the density difference of output images. The detection area is set within one lane on the road. The total number of pixel densities in the detection area is sequentially measured, and if there is a change more than a predetermined value compared with the previous value, the number of vehicles on the road is counted by counting that one vehicle has passed in the lane. A traffic volume measuring device characterized by counting traffic. 2. When the road has a plurality of lanes, the detection area is provided in each lane, and the number of vehicles on the road is counted to count the number of vehicles on the road. Traffic measurement device described. 3. The traffic volume measuring device according to claim 1, wherein the count value of the vehicles passing through the detection area within the measurement time is output as the traffic volume within a predetermined time. 4. The count value of vehicles that have passed through the detection area within a measurement time calculated from the traveling speed of the vehicle is output as a traffic volume within a predetermined range.
The traffic volume measuring device according to the item 2 or item 3.