JPS6033354B2 - Image correlation device with optical filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image correlation device that can obtain a correlation image in a television image without imposing any restrictions on the shape or background of an input image.

Conventionally, image correlation devices input images from a television camera and perform correlation calculation processing, which uses an ultrasonic optical modulator and a Fourier transform optical system to perform optical correlation calculations, and then displays the autocorrelation image on a television receiver. There is something. However, in such a conventional device, due to the operating principle of repeatedly and continuously performing finite interval correlation calculations, the length of the video signal of the input image obtained by the television camera must be 1'2 or less of the horizontal synchronization time. Therefore, when capturing an input image, restrictions must be placed on the size of the input image, its position with respect to the camera, and the background. The configuration and operating principle of the conventional device will be outlined below.

FIG. 1 shows a schematic diagram of the configuration of a conventional device. This pupil system focuses on the fact that the video output signal of a commonly used television camera has an appropriate repetition period and frequency band as the input signal of an electro-optic correlator, and uses an electro-optic correlator to perform each horizontal scan. The correlation signal of the video signal is obtained, and a correlation image is constructed on the screen of the receiver. In the image correlating device shown in FIG. A correlation signal of the video signal for each horizontal scan is obtained. This correlation signal is transferred to an image receiving device 10 comprising a synchronizing signal mixer 5 and an image receiver 6.
2, and a correlated image of the input image 1 is displayed on the screen of the image receiver 6. Next, the principle of optical correlation calculation using video signals will be briefly explained.

The correlator 101 is a type of real-time electro-optical correlator that has two ultrasonic optical modulators and a Fourier transform optical system, and applies electric signals to the two ultrasonic optical modulators to f, (
x), f2(x), the correlation output signal C(7) is given by the following equation. C (ding) = 'dii (X-ke) f2 (
X+7)dX...(11'1} Integral interval of formula [1d, d]
is a value determined by the width of the light beam of the Fourier transform optical system.

In addition, the integral calculation is performed by the action of the lens in the optical system, and the movement (delay) of f(x) is automatically performed by the ultrasonic propagation in the ultrasonic light modulator, thereby realizing m-type calculation. be able to. Expression '1} will be explained using an example of autocorrelation calculation. FIG. 2 is a diagram showing how to capture a video signal by the imaging device 100. The television camera 3 is caused to perform two-way horizontal scanning as shown in the figure by the signal generator 2, and a video signal f(Q,
i) obtain. Q' is the coordinate in the horizontal scanning direction, and i is the number of horizontal scanning. This video signal f(Q,i) is a black and white binary signal. f(Q,i) is input to the correlator 101,
FIG. 3 shows how the correlation calculation is performed within the correlator.
Figures 3a and 3b show the state in which the input video signal f(Q,i) is propagated in opposite directions at a speed of 100 seconds by the ultrasonic optical modulator in the correlator, and the central part is Correlation calculation is performed in . The width 2d is the width of the light beam in the correlator, and corresponds to the above-mentioned integration interval.

Also, in the correlator, video signals f(Q, i) and f(Q,
i+1) is performed. Figure c shows the cross-correlation output between f(Q, i) and f(Q, i+1) in the integral interval illusion. As is clear from the figure, f(Q,i)2f(Q,i11) holds true within the optical correlator, and f
The cross-correlation between (Q, i) and f(Q, i11) represents the autocorrelation C(7) of f(Q, i) as shown in the following equation. C (ten, i) = J-ddf (Q one, i) f (Q ten, i) d
Q...■The important point here is that in order to perform the correlation calculation between f(Q, i) and f(Q, i+1) in the integral interval phantom, at least f(Q, i),
There must be a no-signal portion before and after the signal f(Q, i+1) that is 1/sha of the length of these signals.

That is, if the horizontal synchronization time is Th, the length of each horizontal scan of the video signal obtained from the input image must be equal to or less than Th/2, and the remaining portion must be a no-signal section. The above is an outline of the configuration and operating principle of the follower device.

Since the conventional device is used for pattern recognition of simple figures, the above-mentioned no-signal portion is obtained by limiting the width of the input image in the horizontal scanning direction and by making the background black. In addition, a fixed camera is used and the position of the input image relative to the camera is also limited so that the video signal of the input image is correlated at the center of the integration interval illusion. There has been a drawback that it is difficult to obtain correlated images of moving images.The present invention eliminates the drawbacks of such image correlation devices, removes restrictions on the input image size and background, and makes it possible to use a television camera. It is an object of the present invention to provide an image correlation device that can input all images including moving images that can be input.

In order to achieve this object, the gist of the present invention is to form a no-signal portion in the image signal regardless of the size, background, and movement of the input image, so that the lens system and image pickup tube in the television camera An optical filter 22 is placed between the two.

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

FIG. 4 is a block diagram of an embodiment of the image correlation device.

The correlation calculation operation is similar to the operating principle of the conventional device. In the present invention, the optical system part A of the television camera 3 used as a follower device is modified to have a structure as shown in FIG. 5. FIG. 5 shows the installation of an optical filter 22 for restricting the light passing through the lens system 21. The optical filter 22 is arranged between the lens system 21 and the image pickup tube 23. FIG. 6 shows the shape of the optical filter 22, which is arranged so that its lateral direction coincides with the horizontal scanning direction of the image pickup tube 23, and its opening width L is the horizontal scanning direction of the image pickup tube 23. Set the value to 1/2 or less of the length. Further, this optical filter 22 is installed approximately at the center of the light receiving window of the image pickup tube 23. Therefore, it is possible to create a place where no light optically enters the light receiving surface of the image pickup tube 23. As a result, it is possible to obtain from the television camera 3 a video signal in which there is no signal for 1/sa of the horizontal scanning time required for correlation calculation. The present invention has the above-described configuration, and as long as it can be photographed by the television camera 3, it can be input to the present image correlation device without requiring restrictions on its shape, background, or position range. There is an effect that can be done.

Therefore, it is possible to input moving body images, and it is also possible to realize real-time correlation processing of moving images by utilizing the high-speed calculation performance of this image correlation device. Also, since there is no limit on size,
Correlation processing in which the input image is enlarged or reduced using the lens system 21 is also possible, and measurement can be performed with higher precision than with conventional devices. Furthermore, instead of the image receiver, a video tape recorder, an X-Y recorder, etc. can be used as the image receiver, and archival records can also be created.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a conventional device, Fig. 2 is a diagram showing multidirectional horizontal scanning of an image, Fig. 3 is a diagram showing a correlation calculation using a video signal obtained by bidirectional horizontal scanning, and Fig. 4 is a diagram showing a correlation calculation using a video signal obtained by bidirectional horizontal scanning. FIG. 5 is a diagram showing the internal configuration of the section A in FIG. 4, and FIG. 6 is a front view of the optical filter 22. 10 Kawama image pickup device, 101 correlator, 102 image receiver, 1 input image, 2 sweep signal generator, 3 television camera, 4 synchronization signal separation circuit, 5 mixer, 6 image receiver,
21 is a lens system, 22 is an optical filter, 23 is an image pickup tube, and f(Q, i) and f(Q, i+1) are input video signals. Figure 1 Figure 2 Figure 5 Figure 6 Figure 3 Figure 4

Claims (1)

[Claims] 1. An imaging device 100 having a lens system 21 and an image pickup tube 23, and equipped with a television camera 3 that outputs a video signal of an image to be correlated; and a correlator 101 that inputs the video signal and outputs a correlation signal. In an image correlating device having an image receiving device 102 having an image receptor that receives the output signal of the correlator and displays a correlated image; a photochemical filter having an aperture width for limiting light passing through the lens system to 1/2 or less of the scanning length so that only light near the center in the horizontal scanning direction is irradiated onto the imaging tube surface; 22. An image correlation device equipped with an optical filter.