JPH0481999A - Detector for mobile object - Google Patents

Abstract

PURPOSE:To detect a high speed moving object without complicating an algorithm and a hardware by providing an image pickup device of a line scanning type and a sensing device. CONSTITUTION:The device is equipped with an illuminating device 2, line scanning type fixed image pickup device 1, signal processor 6, sensitive device 5, controller 7, and power device 8. The illuminating device 2 emits light quantity enough for the image pickup device to pick up, to an object. Then, the image pickup device 1 picks up the side face of the moving object, and the signal processor 6 detects the object from the signals of both the image pickup device 1 and the sensing device 5, and measures the length, height, and instantaneous speed of the passing object and others. Thus, it is not necessary to design the special and exclusive high speed hardware even in a system required for a real time process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a system in which an arbitrary number of objects of arbitrary size and arbitrary shape move in a fixed direction at an arbitrary time and at an arbitrary time interval. In particular, it relates to a moving object detection device capable of detecting the passing of the object, measuring the instantaneous speed of the object when it passes in front of the camera, and its length in terms of height and direction of travel, particularly for monitoring and measuring road traffic. This invention relates to a detection device used in a device or the like.

[Conventional technology]

Conventionally, most moving object detection devices using image information have attempted to detect differences between a plurality of two-dimensional images arranged in chronological order.

That is, a moving object is imaged from the side, and a two-dimensional image with the object's traveling direction X and height direction y in the rain space direction as the axes is used as input information, and the image at time t1 and the image at time t2 are The basic principle was to detect differences between images.

[Problem to be solved by the invention]

The conventional moving object detection device described above has to process multiple two-dimensional images, so the processing content is complex and requires a large amount of calculation, and the hardware is large and expensive, making it particularly difficult to perform real-time processing. The disadvantage is that special, dedicated, high-speed hardware must be designed in systems that require it.

[Means to solve the problem]

The moving object detection device of the present invention includes an imaging device that optically scans a surface perpendicular to the path of a moving object to capture a one-dimensional image, and a surface scanned by the imaging device on the path. a sensing device that detects the passing of a moving object at a distant position; a background image memory that stores a background image captured by the imaging device; and a background image signal from the background image memory and a signal of the image captured by the imaging device. a comparison circuit for determining a signal difference; an edge detection circuit for detecting edges of a binary image obtained by binarizing the output of this comparison circuit; The apparatus is characterized in that it includes a speed detecting means for determining the moving speed of the moving object from the signal.

[Effect]

One possible application field of the present invention is the measurement of road traffic volume and vehicle type determination, but if the motion characteristics of a vehicle are limited to a short period of time, it can be approximated as a uniform linear motion in a constant direction. It can be considered as Therefore, in cases where it can be considered as uniform linear motion, a two-dimensional image is not required for object detection, and the amount of processing information can be significantly reduced by using a one-dimensional image captured by a line-scanning solid-state image sensor. . Furthermore, due to this reduction in processing amount, the time required to capture an image is proportional to the reciprocal of the number of scanning lines, so it can also be applied to the detection of high-speed moving objects.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

A moving object detection device according to an embodiment of the present invention shown in FIG.
It has an illumination device 2, a line scanning fixed imaging device 1, a signal processing device 6, a sensing device 5, a control device 7, and a power supply device 8. The illumination device 2 emits a sufficient amount of light to the subject for the imaging device to image, the imaging device 1 images the side of the moving object, and the signal processing device 6 detects the object from the signals from the imaging device 1 and the sensing device 5. Detects the length, height, and instantaneous speed of passing objects. FIG. 2 shows a detailed block diagram of the signal processing device 6. The sensing device 5 detects the passage of an object, and if the object is metal, a simple metal sensor may be used. This is for remotely controlling the device 2. The power supply device 8 supplies power to each of the above-mentioned devices.

Next, the basic operation of this embodiment will be explained with reference to the drawings.

3 and 4 are conceptual diagrams showing the basic operation of this embodiment. The line-scanning solid-state imaging device 1 is installed in an alley of a road lane to be detected in a -dimensional CC'D, and constantly scans and images the side surface of a passing vehicle in the height direction. When there are no cars on the road, the light beam emitted from the illumination device 2 scans the background plate 3 and images it. When there are no cars on the road, the light beam emitted from the illumination device 2 hits the background plate 3, and the imaging device 1 images the reflected light.

The surface of the background plate 3 is made black in order to increase the change in brightness when a car passes by. When the car 4 rushes into the front side of the imaging device 1, the imaging device 1 takes in reflected light from the car, so the optical path from the light source becomes shorter, and the color of the car body is brighter than the color of the background plate. Due to the following reasons: 1. The brightness changes rapidly.

When this embodiment is used outdoors, it is affected by environmental conditions such as the weather, the position of the sun, the time of day, and ambient light, so it is necessary to prevent false detections due to this. Therefore, the output of the arithmetic circuit 16, which is the detection result, is constantly monitored, and if it is determined that the car is not present on the imaging device, the contents of the background image memory 11 are updated every scan.

Cars are basically detected based on the difference between the input image and the background image. The difference is calculated by the comparator circuit 10 of FIG. The -dimensional input buffer 9 stores the output of the imaging device 1 for each scan. At this time, if the determination result of the arithmetic circuit 16 is an undetected state, the contents of the input buffer are transferred to the background image memory 11.

The comparator circuit 10 compares the contents of the input buffer f(x)(x
=1.2. ..., n, n is the number of pixels) and the background image g(x) (x=1.2...) stored in the background image memory 11.
..., n), the difference d (x) d(x) = f(x
) g(x) (x=1. 2. ..., n> is found.

The binarization circuit 12 binarizes the output of the comparison circuit 10 and sends it to the edge detection circuit 14. The arithmetic circuit 16 detects a run (continuous black pixels) within one scanning line from the output of the edge detection circuit 14, and records the scanning line number, time, run start position, and run end position in the run information list 17. If a run is found on a scanning line, it is considered to represent a part of the vehicle body, so by looking at the contents of the run information list 17, it is possible to determine whether or not there is connectivity with the run on the previous scanning line. It can be investigated. If a run connected to the previous scan line is found, the run is identified as part of the same object and the vehicle ID 15 is not counted up.

If there is no run on the previous scanning line, it is assumed that another vehicle has entered the vehicle, and the ID counter 15 is used to count up the vehicle ID. Also, there is a run in the previous scan line,
If it has no connectivity with the run of the current scan line, or if there is no run in the current scan line, it is assumed that the vehicle has passed and the contents of the run information list 17 are cleared. Furthermore, the vehicle height of a passing vehicle can be measured by determining the minimum value of the run start position and the maximum value of the run end position within the same vehicle ID.

On the other hand, when the edge detection circuit 14 detects the leading edge of the vehicle, the timer 13 starts operating and measures the time Δtl (sec) until the sensing signal from the sensing device 5 arrives. This is Figure 3.

In FIG. 4, the average moving speed V during this period is considered to be the time from when the vehicle rushes in front of the imaging device 1 until the front end of the vehicle passes in front of the sensing device 5. , where a (m) is the distance between the sensing devices 5, it is calculated as follows: v=a/Δtl(m/5ec). Furthermore, by using the run information list, the vehicle length 1 (m) can be calculated as the time Δt from the moment when the head of the vehicle body is detected until the moment when the vehicle completes passing.
2, 1=v·Δt2(m). Note that this calculation is executed by the arithmetic circuit 16.

〔Effect of the invention〕

As explained above, the present invention includes a line scanning type imaging device,
The sensing device is effective in detecting high-speed moving objects without complicating algorithms and hardware.
It also has the advantage of being able to measure the length, height, and instantaneous velocity of an object.

FIG. 3 is a side view and a plan view for explaining the operation of the embodiment.

1... Line-operated solid-state imaging device, 2... Illumination device, 3
...Background board, 4...Car, 5...Sensing device, 6
... Signal processing device, 7... Control device, 8... Power supply device, 9... -dimensional human power buffer, 10... Comparison circuit, 11... Background image memory, 12... Two Value conversion circuit, 13... Timer 14... Edge detection circuit, 15.
...ID counter 16...Arithmetic unit, 17...Run information list.

Claims (1)

[Claims] An imaging device that captures a one-dimensional image by optically scanning a surface perpendicular to the path on the path of a moving object; a sensing device for detecting, a background image memory for storing a background image captured by the imaging device, and a comparison circuit that calculates a difference between a background image signal from the background image memory and a signal of the image captured by the imaging device; an edge detection circuit that detects edges of a binarized image obtained by binarizing the output of this comparison circuit; an arithmetic circuit that calculates the dimensions of a moving object from run information obtained from the output signal of this edge detection circuit; A moving object detection device comprising: a circuit; and speed detection means for determining the moving speed of the moving object from a signal from the sensing device.