JPH04110715A - Device for measuring high speed body - Google Patents

Abstract

PURPOSE:To secure the high accuracy of an image-formation position by memorizing an image photographed by two digital still video cameras as the data, and processing the memorized data on the basis of a predetermined algorism. CONSTITUTION:Cameras 2, 3 are located with a certain distance so that optical axes thereof are in parallel with each other and they are located on one line laterally, and a moving body 1 is photographed by the cameras 2, 3. These cameras 2, 3 are controlled by a camera synchronous control circuit 4 so that the shutter timing of CCD picture elements built in the cameras 2, 3 are in the predetermined relation. The light reflected by the body 1 is converged by lenses 5, 6, and is divided by half mirrors 7, 8, and an image is respectively formed by the CCD elements 9, 10 and 11, 12, and an optical system without parallax is formed. The image photographed by the elements 9 - 12 of the cameras 2, 3 is memorized as the data by a high speed access memorizing device, and while the memorized data is processed by a measuring means on the basis of a predetermined algorism.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a digital S system that continuously photographs the motion of a high-speed object in a short period of time and analyzes the motion of the object, such as the velocity of the object, from the photographed results. V C (Still video
This invention relates to a high-speed object measuring device using a camera.

(Prior Art) There is a demand for photographing objects moving at high speed and performing various measurements based on the photographic results.

One of the devices that can perform such measurements is a high-speed camera that rotates an optical prism at high speed and exposes the image of the object to be measured, which is reflected by the rotating surface of the rotated optical prism, onto a silver halide film. .

This high-speed camera shoots on silver halide film, so it has excellent image quality, but it has the drawback of not being able to see the results in real time, and lacks immediacy.

Furthermore, it is difficult to match the timing of photographing a moving object with the rotational speed of the optical prism, resulting in high running costs.

Other devices include a system in which a strobe is emitted continuously and an image of the object to be measured is photographed on a silver halide film at the timing of the flash, but this method has the disadvantage that the power source for the strobe is large.

Furthermore, there is a high-speed video device constructed using a high-speed CCD solid-state imaging device that uses a parallel processing CCD readout method, but while this device is fast, it has the disadvantage that it is expensive.

The purpose of the present invention is to solve the drawbacks of each of the above devices, and instead of using a special high-speed CCD, it uses a CCD for commercially available video cameras that can freely set the shutter time by controlling the storage time. It is an object of the present invention to provide a relatively inexpensive high-speed object measuring device that can ensure the immediacy of digital SVC playback and observe moving objects by connecting a multi-screen display device.

(Means for Solving the Problems) In order to achieve the above object, the high-speed object measuring device according to the present invention uses two digital stills separated by a certain distance so that their optical axes are parallel and in a horizontal line. A video camera is arranged, and each of the cameras has a parallax-free optical system that splits incident light into two using a half mirror, and a solid-state image sensor that can change the shutter time by controlling the storage time. The drive timing of one solid-state image sensor of each camera is synchronized, and the drive timing of the other solid-state image sensor of each camera is synchronized with the drive timing of the other solid-state image sensor of each camera. a synchronization control circuit that synchronizes by delaying the timing by a certain period of time; a high-speed access storage device comprising a semiconductor memory that stores images taken by each solid-state image sensor of each of the cameras as data; and storage in the high-speed access storage device. and measuring means for processing the obtained data according to a predetermined algorithm.

According to the configuration, the speed of a moving object can be measured based on the principle of triangulation.

Furthermore, since the image data is stored in a memory location corresponding to the position of the object, the stored data can be effectively used for various observations of the object.

(Example) Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a system using a high-speed object measuring device according to the present invention.

Cameras 2 and 3 are arranged at a certain distance apart so that their optical axes are parallel and line up horizontally, and each camera is capable of photographing a moving object 1 (a car in this example).

The cameras 2 and 3 are connected to a camera synchronization control circuit 4, and are controlled by the camera synchronization control circuit 4 so that the shutter timings of the CCD image sensors built in the cameras 2 and 3 are in a predetermined relationship.

The camera synchronization control circuit 4 has an extremely short COD accumulation time.
(t=63.5 μs), and the timing of reading from two COD sensors built into each camera into a CCD type register is controlled to be shifted by, for example, 1 ms to take a picture.

FIG. 2 is a schematic diagram showing the positional relationship of each camera and details of the internal optical system.

Two cameras 2 (camera-R) and 3 (camera-L)
The distance between is the triangulation baseline length d.

The camera 2 includes a lens 5, a half mirror 7 placed on the optical axis of the lens, and a camera C placed behind the half mirror 7.
A CD image sensor (CCDSR) 9 and a CCD image sensor (CCD sp) 10 arranged to the left of the half mirror 7
It is equipped with

The reflected light from the moving object is converged by a lens 5 and split into two by a half mirror 7, each of which is sent to a CCD image sensor 9.
and 10, forming a parallax-free optical system.

The camera 3 has a similar configuration, and the light incident from the moving object via the lens 6° half mirror 8 is transmitted to the CCD image sensor (CCDSL) 11 and the CCD image sensor (CCDs).
:) Imaged at 12.

FIG. 3 is a circuit diagram showing an embodiment of the circuit configuration of a digital SVC provided for each CCD image sensor.

Each camera has two built-in circuit units.

An input terminal of the external synchronization control signal 30 is connected to the camera synchronization control circuit 4.

The light reflected from the moving object that enters through the lens 15 is split into two by a half mirror (not shown in FIG. 3), and the amount of the split light is adjusted by the iris 16.

The calibration value of the iris 16 is determined and controlled by the iris drive circuit 19 based on the photometry results.

The light that has passed through the iris 16 has its high frequency portion removed by an optical LPF 17 and reaches a CCD image sensor 18 .

The CCD image sensor 18 is driven by a C'CD drive circuit 20, and an electronic shutter operation is performed.

After the image output of the CCD image sensor 18 is amplified by a predetermined amount by an amplifier 21, the γ value and white balance are adjusted by an adjustment section 22.

The image signal adjusted by the γ value and white balance adjustment section 22 is input to the A/D conversion section 23, and converted into a digital signal in this circuit.

The digital signal has an 8-bit configuration and is input to the memory card 25 via the signal processing circuit 24.

In the signal processing circuit 24, the 8-bit signal is converted into a predetermined format for storage in the memory card 25.

The memory card 25 stores the digital signal from the signal processing circuit 24 in a storage area designated by the address control circuit 26.

The storage operation to the memory card 25 is performed under the control of the CPO 28.

The CPU 28 controls the memory card 25 via the interface circuit 27 and also controls the addressing operation of the address control circuit 26.

On the other hand, the external synchronization control signal 30 is transmitted to the interface circuit 33.
The signal is inputted to the signal generation circuit 29 via.

The signal generation circuit 29 is composed of a crystal oscillator, and based on the external synchronization control signal 30, the signal generation circuit 29 sends a signal to the amplifier 21. γ value and white balance adjustment section 22.
The signal is supplied to the A/D converter 23 and the signal processing circuit 24.

The interface circuit 33 and signal generation circuit 29 are CP
It is under the control of U28, and the above-mentioned storage operation of the image signal to the memory card 25 is performed in synchronization with the external synchronization control signal.

A release 31 is connected to the CPO 28, and a terminal 32 for inputting an external release signal 32 is further connected to the release 31.

The operation of reading the image signal of the CCD image sensor 18 and starting storage can be performed by operating the release 31 or by an external release signal 32.

FIG. 4 is a waveform diagram for explaining the purely electronic shutter operation of the CCD image sensor.

The electronic shutter operation controls the period (accumulation time) during which photoelectrons are stored in the COD sensor, that is, the period (accumulation time) from the time when the electrons stored in the sensor are forcibly swept out and the storage starts until the time when the stored charge in the sensor is transferred to the COD. It will be done as follows.

The shutter time is the time from the start of accumulation until a readout pulse is input from the CCD image sensor based on an external synchronization control signal.

FIG. 5 is a waveform diagram for explaining the relationship between the readout timings of the CCD image pickup elements of each camera during continuous shooting.

CCD5R and CCD built into Camera-R and Camera-L
The read timings of 5L have the same phase relationship.

In addition, any phase of CCD sd and CCD5 is in phase,
Moreover, the successive timing is delayed by Δt from the CCD sR.

By reading out with this phase relationship, CCD5R
A still image at time t is stored as an image on CCD s and CCD s. Also, the images of CCD st4 and CCD w are at time t1.
still images are stored.

As a result, at time t1, the left and right CCD5L, :! :C
Two still images of CD5R are obtained.

Similarly, at time t2, two still images are obtained from the left and right CCD 5pi and CCD sd.

The speed of the moving object can be calculated from the above still image data and the time from time t1 to t2, that is, Δt.

In particular, since Δt can be set to an extremely short value of several hundred μs, the speed of an object moving at high speed can be measured.

FIG. 6 is a diagram for explaining the positional relationship of images formed on the COD light receiving surface of a moving object.

The method for measuring speed will be explained below.

For ease of understanding, we will focus on one point (a point with large contrast) on the moving object 1 in FIG. 1.

Let us assume that a point on the moving object 1 at time t1 is M, and that point moves to M' at time t2.

At time t1, a point M of the moving object forms an image on the light-receiving surface of the CCD milk of camera-L.

Let the object image be SL.

Similarly, one point M forms an image on the light receiving surface of the COD SR of camera-R.

Let the object image be SR.

At time t1, the imaging data is read out and stored.

At this time t1, an image of M is also formed on the light receiving surfaces of CCD5bi and CCD sd, but since no readout pulse is input to these CCDs, the data of this image is not stored.

Similarly, at time t2, M' is CCD5 of camera-L.
L and CCD sa: and camera-R CCD5R and CCD
5t(, but at the same time CCD s+
Only the images of CCD sd and CCD sd are read out and stored. Let the object images at this time be SL' and SR''.

Figure 7 shows the points M and M' of the moving object, and the respective images 5LSR and S.
It is a figure which shows the coordinate of L' and SR'.

In FIG. 7, f; lens focal length Xsl; coordinate point Xsr on the X-axis of image SL; coordinate point Xsl'' on the X-axis of image SR; coordinate point xsr' on the X-axis of image SL'';
Assuming that the coordinate point Z on the X axis of the image SR' is the distance to M, and the distance to M l is the following equation.

Z=f x (X-d) / (d-Xsr) -<
1) Z' = f x (X' - d) / (d
-Xsr') -(2) Z=fxX/X5l-(
3) Z = f XX' / -Xsl' river (41 above (
From formulas 1) and (3), X'--Xsl' xd/ ((d-Xsr'
)+Xsl'...(6) Furthermore, from (3) and (5), z=fxd/((d
6), Z' = f xd/ ((d-Xsr')
+Xsl') ・=(81 and (5) f6
) From f7) and (8), x, x', z and Z' can be calculated because they can be expressed by known values of Xsl, Xsr, Xsl'Xsr' and d.

X=-Xslx d/ ((d-Xsr) +X5l
) −(51Δt) From equations (2) and (4) above, the moving distance of the moving object is −IZ Z)2 − (X' X ) 2 ) I/2...(9) Therefore
It can be determined by V=L/Δt...0ω.

The above calculations can be performed by an arithmetic circuit including a CPU equipped with an algorithm for performing such calculations.

The above Δt can be arbitrarily set by adjusting the timing of sequential output to each CCD image sensor of the camera synchronization control circuit 4, and can be set at a time that is easy to measure according to the speed of the moving object.

(Effects of the Invention) The apparatus according to the present invention described above has the following features.

First, by using a CCD sensor array with high positional accuracy using integrated technology and forming a parallax-free imaging optical system using a half mirror, highly accurate triangulation becomes possible.

In addition, accurate time control of the CCD's high-speed electronic shutter and crystal oscillator, and accurate synchronization timing with each CCD ensure
Since the CD drive is synchronized and the image signal is digitized and the image position and address are stored in the semiconductor memory in a correlated manner, high accuracy of the imaging position can be ensured.

In view of the above points, according to the present invention, a relatively inexpensive and highly accurate high-speed moving object measuring device can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a system using a high-speed object measuring device according to the present invention, and FIG. 2 is a schematic diagram showing details of an imaging unit of a camera with a built-in CCD imaging device using a triangulation method. FIG. 3 is a circuit block diagram showing an example of a digital SVC circuit provided for each camera's CCD image sensor, and FIG. 4 is a waveform diagram for explaining the electronic shutter operation that controls the CCD storage time. Fig. 5 is a waveform diagram for explaining the shutter operation during continuous shooting, Fig. 6 is a diagram showing the positional relationship of images formed on the CCD light receiving surface of a moving object,
FIG. 7 is a diagram showing the coordinates of the imaging position relationship of a moving object on the CCD light receiving surface. ■...Moving object (car) 2...Camera-R 3...Camera-L 4...Camera synchronization control circuit 7.8...Half mirror 9, 10, 11, 12, 18/CCD Image sensor 20...
・CCD drive circuit 23...A/D conversion section 25...Memory card 26...Address control circuit 28...CPU

Claims (1)

[Claims] Two digital still video cameras are arranged at a certain distance apart so that their optical axes are parallel and line up horizontally, and each camera splits incident light into two by a half mirror. It is constructed by disposing a parallax-free optical system and a solid-state image sensor that can change the shutter time by controlling the accumulation time on each of the two branched optical paths, and one solid-state image sensor of each of the cameras. a synchronization control circuit that synchronizes the driving timing of the imaging devices and synchronizes the driving timing of the other solid-state imaging device of each of the cameras by delaying the driving timing of the one solid-state imaging device by a certain period of time; It is characterized by comprising a high-speed access storage device made of a semiconductor memory that stores images taken by each solid-state image sensor as data, and a measurement means that processes the data stored in the high-speed access storage device according to a predetermined algorithm. High-speed object measurement device.