JPS6033356B2 - image correlation device - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an image correlation device that obtains a horizontal scanning direction convolution image of a television image in real time. Conventionally, image correlation devices that input images from a television camera and perform correlation calculation processing use an ultrasonic light modulator and a Fourier transform optical system to perform optical correlation calculations. There are devices that display only horizontal scanning direction autocorrelation images, but such image correlation devices have the following drawbacks in terms of performance and operation. (1) Since only correlated images can be displayed on the receiver screen, it is difficult to compare and examine input and output images. Therefore, a receiver dedicated to displaying the input image is required, and
These two image receivers dedicated to input and output images must have the same screen size and performance. t2' Since the finite interval correlation calculation is repeatedly and continuously performed, in terms of the operating principle, the screens corresponding to 1'4 left and 1'4 of the correlation image display receiver screen, that is, half of the entire screen, are not used for display.

[3] In order to repeatedly and continuously perform finite interval correlation calculations, due to the operating principle, the length of the input image in the horizontal scanning direction must be less than 1/sha of the horizontal synchronization time after conversion to a binary pulse video signal. First, due to the structure of the optical correlator, there is a condition that the binary pulse video signal must not exist in the range of 1/4 synchronization time before and after the horizontal synchronization pulse. For this reason, restrictions are placed on the size, composition, and background of an image when capturing an input image. [4- Correlation Image Correlation values at each point are expressed in brightness, so the accuracy of quantitative display is poor due to the nonlinear voltage versus brightness characteristics of the cathode ray tube. The authors first published the journal of the Society of Electronics and Communication Engineers in March 1979.
Month Vol. 621A No. 3 "One configuration method of an image correlation device using an ultrasonic light modulator and a TV camera"), that is, the configuration and operating principle of a conventional image correlation device will be described below. FIG. 4 shows a schematic diagram of the configuration of the attached device. The outline of the intention behind the production of this device was to focus on the fact that the video output signal of a commonly used television camera has an appropriate repetition period and frequency band as an input signal to an ultrasonic optical modulator. The one-dimensional autocorrelation function of the video output signal for each horizontal scan is detected by an optical correlator having a sensor, and the one-dimensional autocorrelation function of the video output signal for each horizontal scan is configured and displayed on the image receptor screen. The goal is to obtain an autocorrelation image. In the apparatus shown in FIG.
A television camera 14 that performs bidirectional horizontal scanning using a Z triangular wave.
A synchronization pulse separation circuit 1 is used to separate the obtained composite video signal into a video signal and horizontal and vertical synchronization pulse signals.
Add to 0. Since the video signal separated here satisfies the conditions for optical correlation calculation, which will be described later, the video signal pulsing circuit 9
The signal is then sent to and compared with a set function value and converted into a binary pulse video signal representing only black and white binary values. This 200 million pulse video signal is generated by a pair of sine wave oscillators la, which can modulate the pulse amplitude.
lb as an external modulation signal. The sine wave oscillators la and lb oscillate at the resonant frequency of the ultrasonic transducers constituting a pair of ultrasonic light modulators 5a and 5b arranged in the optical correlator, and the oscillated waves are generated by the oscillator. The signal is amplitude-modulated by the binary pulse video signal and applied to the ultrasonic light modulators 5a and 5b. The optical correlator is constructed as follows. After enlarging the light beam with a lens using the Caesar 4 as a light source, the ultrasonic light modulators 5a and 5b
incident on . The pair of ultrasonic light modulators 5a and 5b are arranged so that the directions of the ultrasonic waves are opposite to each other, and the light transmitted therethrough is converged by a lens to form a twill point on the focal plane. A spatial light intensity filter 6 is arranged in the focal plane,
The light passing through this filter is photoelectrically converted by a photoelectric converter 7 and becomes an output current of an optical correlator. Note that the principle of optical correlation calculation will be explained in detail later. The synchronization pulses separated by the synchronization pulse separation circuit 1 are sent to the horizontal synchronization time delay circuit 11 and are applied to the mixer 12 after being time-delayed. This mixer 12 adds a delayed synchronization pulse to the correlation output signal obtained by the photoelectric converter 7 to create a composite video signal to be a correlation image.
If the delay time of the horizontal synchronization time delay circuit 11 is set to approximately 1/2 of the horizontal synchronization time, and the composite video signal is formed into an image by the image receiver 16, the autocorrelation image of the input image 13 is displayed on the screen. can be displayed in the center. Next, the principle of optical correlation calculation will be described. The image signals obtained by bidirectional horizontal scanning, the scanning direction of which is reversed for each scan, are spatially inverted, delayed, and shifted by two ultrasonic optical modulators, and then integrated by a lens to produce images that are adjacent to each other, i.e., the screen. The above is an outline of how the cross-correlation function between video signals in a vertical relationship is obtained by approximating the auto-correlation function. As shown in Figure 5, the input image is a binary image P(Q,B
), and the video signal obtained in the n-th horizontal scan counting from the vertical synchronization pulse is f(Q, n). As shown in FIG. 6, the ultrasonic signal that has been shaped into a binary pulse video signal and amplitude-modulated by f(Q, n) is applied to an ultrasonic transducer in an ultrasonic optical modulator. Since the ultrasonic light modulators 5a and 5b are arranged so that the directions of ultrasonic wave propagation are opposite to each other, the ultrasonic signals in the ultrasonic light modulators are u(x, n), u
It can be written as (1×, n). The ultrasonic light modulator 5a is made to have a longer length in the ultrasonic traveling direction than the ultrasonic light modulator 5b, and the time for the ultrasonic signal u(x, n) to reach the laser beam east is u(
1 ×, n) reaches the same time by 1 horizontal scanning time 63
．． Delayed by 54 seconds. Therefore, the ultrasonic signals that overlap within the laser beam are u(x, n) and u(x, n+1).
The superposition of two signals within the optical system is expressed by a product operation, and the convergence effect of the lens is expressed by an integral operation. Also u(x, n)
, u(1×, n11) are moving at the ultrasonic velocity v. Therefore, only the diffracted light generated by the ultrasonic signal is detected by the spatial light intensity filter 6 and photoelectrically converted. It is known that by doing this, the following correlation output c(t,i) can be obtained as a current value. Here, d represents the width of Caesar-Koto. g(x,n) represents the hull vertical line of u(x,n), and is obtained by linearly converting Q of f(Q,n) to x. In this {1l formula, g(x,i)nig(1×,i11)...
(If we apply the relationship 2', c(t, i) represents the autocorrelation function of g(x, i), that is, f(Q, i). c(t, n), f(Q , n) are both functions of the number of horizontal scans n.Therefore, c(t, n) can be expressed as f(Q, n)
If the image is constructed using the synchronization signal of , a horizontal scanning direction autocorrelation image of the input binary image is obtained. As a condition for obtaining independent c(t, n) for each n by executing formula 3, there must be a no-signal part of equal length before and after the video signal. The maximum length of the signal is limited to 1/2 of the horizontal synchronization time. In addition, when executing equation {1) using an optical correlator, g(x, i) in equation (1) is replaced by a binary real number function in order to avoid the square characteristic during photoelectric conversion in the photoelectric converter 7. need to be,
Specifically, the input image is limited to a black and white binary image as in the conventional device, or the video signal pulsing circuit 10 with a set function value is used.
is necessary. The above is the configuration and operating principle of the follower device. Since the purpose of the conventional device is to recognize patterns of simple figures or letters and symbols, various limitations arising from the above-mentioned operating principle are overcome by limiting the operation of the device. In other words, the generation of no-signal parts is done by fixing the TV camera and placing the input image with a limited horizontal length on a black background, and the binarization of the video signal is done by converting the input screen itself into a black and white binary image. I am doing it. In addition, there are problems with the performance and operation of the conventional device as listed in items {1 to {4] above. The present invention aims to compensate for the drawbacks of the image correlation device described above, and to make the device more practical and functional by adding new devices. That is, an object of the present invention is to provide an image correlation device that displays a convolution image that is effective in detecting the distribution state and position of an input image. Furthermore, it is characterized by simultaneously displaying the input image and the correlated image on the left and right sides of the center of the receiver screen for simultaneous comparison of input and output images. To achieve this objective, [1'] In order to form a no-signal portion in the video signal regardless of the size or movement of the input image, a light intensity filter was placed on the light incident surface of the image pickup tube in the television camera. {2) A unidirectional horizontal scanning television camera is used instead of a bidirectional horizontal scanning television camera for image input in order to obtain the reverse video signal within the ultrasound light modulator necessary to perform spatial convolution operations. did. FIG. 1 is a block diagram of an embodiment of an image correlation apparatus for displaying convolution images according to the present invention. In this device, an imaging device 100 such as a television camera is horizontally scanned in a single direction to obtain a video signal of an image to be convolved. FIG. 8 shows a comparison between autocorrelation a and convolution b. The same figure al shows the peak input image binary signal, and the signal whose direction is temporally reversed obtained by bidirectional horizontal scanning changes its direction spatially again in the ultrasonic light modulator, and the velocity v. It shows a state in which they overlap while moving. Am in the figure represents an autocorrelation waveform at this time. The autocorrelation waveform has a symmetrical shape, and the center value represents the integral value of the total signal, that is, the magnitude of the total signal, and the correlation value corresponding to each t value is a measure indicating the distribution state of the period t in the input signal. I know what will happen. Now, if the convolution obtained by the present invention is expressed as an equation, it has the following form. v is the ultrasonic velocity, and d is the width of the light east. This type of operation can be easily performed using an autocorrelation operation configuration in an optical correlator in which the sign of (vt) and x, ie, the spatial direction, can be easily changed. Figure 8 bl, row As shown in this figure, by simply using the video signal obtained by unidirectional horizontal scanning, f(x) and f(1x) can be spatially distributed within the two ultrasonic light modulators. Appears in bm in the figure represents the cross-correlation between 1 and 0, that is, the convolution of 1 signals. ■As shown in the formula, the convolution regarding f(x) is the autocorrelation of f(x) and f(x),
) includes two types of calculation contents: cross-correlation.
Therefore, in the combo IJ application, it is possible to detect a periodic distribution, which is a feature of autocorrelation, and a relative position, which is a feature of cross-correlation, at the same time. In the convolution signal shown in Figure 8 bm above, the interval T between the peaks of the signal is
,,T2 represents the periodicity of the input signal f(x), and the shape of the entire signal represents the partial twist of f(x). In addition, when f(x) is not biased, that is, when f(-x) is symmetrical, equation (4) is isomorphic to the above-mentioned glue equation that expresses autocorrelation, and convolution and autocorrelation This convolution signal is combined with the synchronization signal and video in the mixer 12 of FIG. The calculated 1/2 horizontal synchronization time was changed from 32 msec to 1/4 horizontal synchronization time of 6 msec. Figure 7 shows the correlation between the input image and the center on the screen of the image receptor 16 based on these results. This indicates that the image can be displayed.As a result, there are
The input image and its convolution image can be displayed.
The input image displayed on the image receiver can be either a pulse image converted into a black and white binary image or an input image by switching with the switch No. 17 in FIG. The present invention has the above-described configuration, and has the effect that, as long as the image can be photographed by the imaging device 100, the horizontal scanning direction convolution image of that image can be simultaneously compared and observed on the same picture tube as the input image. A convolution image has both the characteristics of an autocorrelation image and the characteristics of a cross-correlation image, and when an image can be input by an imaging device as in the present invention, it can be used to detect objects that move slowly and whose internal distribution state changes. If you use a fixed imaging device to take pictures of things that are present, you can display the direction of movement and the state of distribution at the same time, which is very effective.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the internal configuration of the section A in FIG. 1, and FIG. 3 is a diagram showing the light intensity filter 22.
4 is a diagram showing a conventional example, FIG. 5 is a diagram showing bidirectional horizontal scanning of an image, FIG. 6 is a diagram showing a signal timing chart, and FIG. 7 is a diagram showing a signal timing chart. FIG. 8 is a diagram showing a comparison between autocorrelation and convolution. la and lb are sine wave oscillators, 2 is a missing number, 3a and 3b are broadband amplifiers, 4 is a laser, 5a and 5b are ultrasonic light modulators, 6 is a spatial light intensity filter, 7 is a photoelectric converter , 8 is a video signal amplifier, 9 is a video signal pulsing circuit, 10' is a synchronization pulse separation circuit, 11 is a horizontal synchronization time delay circuit, 1
2 is a mixer, 13 is an input image, 14 is a television camera, 1
5 is a bidirectional sweep oscillator, 16 is an image receiver, 17 is a changeover switch, numbers 18 to 20' are missing, 21 is a television camera lens system, 22 is a light intensity filter, 23 is a rice bran image tube, and 10 is an imaging device. , 101 is a correlator, 102 is an image receiving device, A is a position where a light intensity filter is placed, ULM5
a, ULM5b are ultrasonic optical modulators, f(Q,i), f(
Q, i+1) indicates the input image signal. Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Figure 6 Figure 7 Figure 8

Claims (1)

[Claims] 1. An image for displaying the input image 13 or a pulse image obtained by converting the input image 13 into black and white binary, and a convolution image of the pulse image to the left and right with the center of the same screen of an image receiver serving as a border. A correlation device; a lens system 21 and an image pickup tube 23
an imaging device 100 that outputs a composite video signal obtained by unidirectionally horizontally scanning the input image;
A light intensity filter 22 having an aperture width limited to /2 or less
; a sync pulse separation circuit 10 that separates the composite video signal into a video signal and a sync signal; and a video signal pulse that converts the separated video signal into a binary pulse video signal by comparing it with a predetermined threshold. a correlator 101 for receiving the pulsed video signal outputted from the video signal pulsing circuit and outputting a convolution signal; a horizontal synchronization time delay circuit 11 for delaying the synchronization signal output from the synchronization pulse separation circuit in order to display it on a half screen; the separated video signal, the convolution signal output from the correlator, and An image correlation device comprising: a mixer 12 that receives and mixes synchronization signals output from the horizontal synchronization time delay circuit and provides the mixed output to a receiver. 2. The correlator 101 includes a pair of sine wave oscillators 1a and 1b capable of amplitude modulation; wideband amplifiers 3a and 3b whose input signals are the output signals of the sine wave oscillators; A Fourier transform optical system 102 having a pair of ultrasonic light modulators 5a and 5b whose sound wave propagation directions are opposite to each other; a laser 4 which is a light source of the optical system; and a photodetector that detects the output light of the optical system. Filter 6
The image correlation apparatus according to claim 1, characterized in that it comprises: and; a photoelectric converter 7 that photoelectrically converts the output light.