JPS6350758A - Apparatus for measuring speed for moving body - Google Patents

Abstract

PURPOSE:To accurately measure the moving speed of a moving body in a real time, by calculating the moving distance of the moving body from the difference between the positions of the moving body outputted by twice operations of a stationary image sensing camera and projected on a picture. CONSTITUTION:The video signal of the stationary image sensing camera 1 arranged so as to be turned to the moving path 9 of a moving body 8 is converted to a digital signal by an A/D converter 2 and the first signal is stored in a memory 3 and the next signal is stored in a memory 4 and the picture element at the same position is stored in the bits of the addresses corresponding to the memories 3, 4. THese data are subtracted and compared by an image processing part 5 and, as a result, the bits storing the same data of both memories 3, 4 become 0 and the image thereof is erased. As a result, all of images of a background not moving are erased and only two images of the moving body 8 are outputted. An operational processing part 6 calculates the moving speed of the moving body 8 on the basis of the shift of two images of the moving body 8 in horizontal and vertical directions calculated based on the number of picture elements by the processing part 5 to display the same on a display part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a speed measuring device for a moving body that measures the moving speed of a moving body in real time.

('b) Summary of the Invention A speed measuring device for a moving object according to the present invention includes a still imaging camera that takes a still image of the moving object at a certain moment, and images the moving object twice with this still image camera. The moving speed of the moving object is determined based on the difference in the position of the moving object between these two images.

This makes it possible to accurately measure the moving speed of a moving object in real time.

(C) Prior Art As a device for measuring the moving speed of a moving object, there are conventional devices as shown below.

■A device that measures speed using the Doppler effect of ultrasound and radio waves.

■A device that measures movement speed using continuous photographs.

(d) Problems to be Solved by the Invention Here, the device described in (2) has the drawback that accurate measurements cannot be made unless the ultrasonic or radio wave transmitting/receiving device is installed in front of the moving direction of the moving body. However, ultrasonic waves have the disadvantage of being easily affected by wind, and radio waves being susceptible to noise.

In addition, since the device described in (2) generally takes photographs using photographic film, it takes time to develop the film, and real-time speed measurement cannot be performed.In addition, the distance traveled must be read by a staff member, so it is not possible to measure the speed automatically. It was impossible to process.

The present invention has been made in view of these problems, and an object of the present invention is to provide a speed measuring device for a moving object that can accurately measure the moving speed in real time by image processing.

(e) Means for Solving the Problems This invention provides a still imaging camera that takes a still image of a moving object, a means for operating this stationary camera twice at specific intervals, and a method for operating the static camera twice at specific intervals. The present invention is characterized by comprising means for measuring a difference in position of the moving body between two photographed images, and means for calculating a moving speed of the moving body based on this position difference.

(f) Function In the speed measuring device for a moving object of the present invention, a static imaging camera is installed so that the moving path of the moving object is within the field of view, and the static imaging camera operates twice when the moving object is within the field of view. do. The moving distance of the moving object is calculated from the difference between the respective positions of the moving object photographed on the screen output from these two operations, and the moving speed of the moving object is determined from this moving distance and the interval between the two operations. Calculate. The calculated moving speed is output to a display device or the like.

(Embodiment a) FIG. 3 is a diagram showing a schematic structure of a still imaging camera 1 used in a speed measuring device for a moving object, which is an embodiment of the present invention. The "still imaging camera" proposed earlier (Patent Application No. 101740 of 1988) is used. Behind the lens 14, which is an optical system, is a frame transfer type CCD imaging device (hereinafter simply referred to as RCCD) 10. is installed.This CC
D10 is the imaging unit 11. It consists of an accumulation section 12 and a horizontal shift register 13, and the lens 14 includes an imaging section 1.
1 is facing. An amplifier 17 for amplifying the output signal is connected to the horizontal shift register 13.
A signal processing section 18 that edits the amplified signal as a video signal is connected to. The video signal output by the signal processing section 18 is input to an image processing device or the like. On the other hand, C.C.
A driver 15 is connected to each part of D10, and CC
The movement of the signal (charge) within the DIG is performed based on the command (crochet signal) of this driver 15. driver 15
A controller 16 is connected to the controller 16, which determines the timing of outputting a clock signal and controls the driver 15.

External light is imaged by the lens 14 on the imaging unit 11 of the CCD10, and charges are accumulated in each cell depending on the density of the image, and the charges accumulated in the imaging unit 11 are released at a predetermined timing (generally is transferred to the storage section 12 every 1/60 seconds), and the charges transferred to the storage section 12 are outputted column by column (one scanning line) by the horizontal shift register 13.

Here, the exposure method of the still imaging camera 1 will be explained with reference to the exposure timing chart of FIG. Since a typical video device is set to process 60 fields of screen per second, the video camera also operates with 1/60 second as one cycle to comply with that specification.

Since the lens 14 does not have a mechanical shutter, the
The exposure continues for 60 seconds. Therefore, in this device, the charges accumulated in the imaging section 11 are cleared once during a 1/60 second cycle, and the charges accumulated from the time of clearing until the end of the cycle are transferred to the accumulation section 12 as image data. ing. If there is a sufficient amount of light on the subject, a sufficient image can be obtained with exposure for this amount of time. By doing this, the exposure time (shutter speed) in each cycle (field) can be reduced by 1/2 without adding mechanical components.
It can be shorter than 60 seconds. As a result, if the exposure time is set to 11,500 seconds, for example, even when a moving object is photographed, a still image of the object, that is, an image with a clear outline without blur can be obtained.

FIG. 1 is a diagram showing the configuration of a speed measuring device for a moving object, which is an embodiment of the present invention, using the still imaging camera 1. As shown in FIG. The video signal ((output of No. 8 processing unit 18)) of the still imaging camera 1 installed right beside the moving path 9 of the moving body 8 is input to the A/D converter 2. A/D converter converts the video signal manually input as an analog signal into a digital signal and stores it in either of the two image memories A3 and B4.The video signal is read twice during the movement of one mobile object. , the first signal is stored in memory A3
and stores the next signal in memory B4. The video signal is stored in the image memory as a bit image, and pixels at the same position are stored in the image memory A3. It is stored in the corresponding address bit of B4. These data are subtracted and compared by the image processing section 5. As a result of the subtraction comparison, the bits in which the same data was stored in both memories become O, and the image is erased. As a result, all images such as the background that do not move are erased, and only the two images of the moving object are output. Image memory A1 is shown in Fig. 2 (A+, (B)).
The image stored in image memory B is shown in (C) of the same figure.
The figure below shows a screen showing the results of the subtraction comparison. Based on this image, the image processing section 5 calculates the horizontal and vertical deviations (x, y) of the images 31 and 41 of the two moving objects in terms of the number of pixels (bits) and outputs the result to the arithmetic processing section 6.

The arithmetic processing unit 6 calculates the moving speed of the moving object 8 based on the above (x, y), and outputs it to the display unit 7 for display.

Processing in the arithmetic processing section 6 is performed as follows.

The moving distance d (pixels) of the moving object on the screen is determined by the following 2.

d = r Also, the actual moving distance per pixel on the screen 1 (m)
is determined by the moving path 9 of the moving body 8 and the installation position of the still imaging camera l, and this value is set in advance in the arithmetic processing unit 6, so that the actual moving distance L (' m) can be determined by L=dl. Furthermore, since the shooting interval of this still image pickup camera 1 is 1/60 seconds like a general video camera, the moving distance 1 indicates the moving distance in 1/60 seconds. Therefore, the moving speed V (m/s) of the moving body 8 can be determined as follows: V=60L.

Here, the video signal from the still imaging camera 1 may be read out every 1/60 second regardless of whether the moving object 8 passes or not, and only when the moving object 8 enters the field of view of the still imaging camera 1. Image processing section 5. The arithmetic processing section 6 operates as described above.

Furthermore, if a means for detecting the passage of the moving object 8 is provided,
It is also possible to read out the video signal as it passes.

The controller 16 corresponds to "means for operating a still imaging camera twice at a specific interval" of the present invention, and the image processing unit 5 corresponds to "means for measuring a difference in position of a moving object" of the present invention, The arithmetic processing section 6 corresponds to the "means for calculating the moving speed of a moving object based on the difference in position" of the present invention.

In this embodiment, the still imaging camera 1 is installed perpendicular to the moving path 9 of the moving body 8, but even if it is not perpendicular, the inclination between the camera direction and the moving path can be measured and set in advance. Accurate moving speed can be easily determined through arithmetic processing.

Furthermore, even if the inclination is not known in advance, the still imaging camera 1 can capture a clear image of the moving object, so changes in the size of the image of the moving object due to movement can be accurately detected. can be measured. Therefore, if the actual size of the moving object is known in advance, the distance it moves forward and backward can be calculated based on the change in the size of its image, and if the moving speed is corrected using this data, the accurate moving speed can be calculated. You can ask for it.

In this embodiment, a still imaging camera 1 with a substantially faster shutter speed by charge accumulation time control is used as the still imaging camera 1, but a camera having a mechanical shutter (including a liquid crystal shutter, etc.) may also be used. .

(h1 Effects of the invention According to this invention, by using a static imaging camera, it becomes possible to take a clear image of an object moving at high speed without blurring, and the moving object is taken twice by the camera. However, it is possible to automatically calculate the actual moving distance of the moving object based on the moving distance of the image on the screen using the processing device.

Furthermore, by being able to take clear images of moving objects,
It was possible to accurately measure changes in the size of the image, and this made it possible to calculate the distance traveled in the front and rear directions.

This makes it possible to measure accurate moving speed in real time with a fully automated device, and by configuring a system that inputs this data into a control unit, etc., it can be applied to various automatic control fields. is also possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a speed measuring device for a moving object which is an embodiment of the present invention, and FIG.
1 is a diagram showing an image of a moving object taken by a still imaging camera used in the speed measuring device for the moving object, FIG. 3 is a diagram showing a schematic configuration of the still imaging camera, and FIG. 4 is a diagram showing an image of the still imaging camera It is an exposure timing chart. 1 - Still ↑ Most image camera, 2 - A/D converter, 3.4 - Image memory, 5 - Image processing unit, 6 - Arithmetic processing unit, 1O-C
CD, 16-controller.

Claims (1)

[Claims] (1) A still imaging camera that takes still images of a moving object; means for operating the still imaging camera twice at specific intervals; and determining the position of the moving object in the two images taken in the two operations. A speed measuring device for a moving object, comprising: means for measuring a difference; and means for calculating a moving speed of the moving object based on the position difference.