JPS6034315B2 - TV image correlation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a television image correlation apparatus that obtains a horizontal scanning direction cross-correlation image between two television images in real time.

An image correlation device that inputs images from a television camera and performs correlation calculation processing uses an ultrasonic light modulator and a Fourier transform optical system to perform optical correlation calculations, and displays the input image at the center of the television receiver. Some image correlation devices 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. Since the ``2'' finite interval correlation calculation is repeatedly and continuously performed, in terms of the operating principle, the left and right quarters of the correlation image display receiver screen, that is, the screens corresponding to half of the entire screen are not used for display.

{31 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/sa of the horizontal synchronization time after conversion to a binary pulse video signal. Furthermore, due to the structure of the optical correlator, there is a condition that the binary pulse video signal must not exist within a range of 1'4 synchronization times 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. - Because the signal input method uses one television camera, it is not possible to perform cross-correlation calculations between two images.

The authors first published the journal of the Society of Electronics and Communication Engineers in March 1979.
Month Vol. 621A Ship. 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 a conventional 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 pulse signal is sent to the controller and is converted into a binary pulse video signal representing only black and white binary values by comparison with a set threshold value. This binary 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 ultrasonic waves travel in opposite directions, and the light transmitted therethrough is converged by a lens to form a bright spot on the focal plane. A spatial light intensity filter 6 is arranged in the focal plane,
The light passing through the filter 6 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 synchronizing pulses separated by the synchronizing pulse separation circuit 101 are sent to the horizontal synchronizing pulse delay circuit 11, subjected to a time delay, and then added to the overflow combiner 12. 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 pulse delay circuit 11 is set to approximately 1/2, 32 peaks of the horizontal synchronization time, and the composite video signal is formed into an image by the receiver 16, the input image 13
The autocorrelation image of can be displayed in the center of the screen.
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. In the above example, 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
, 8), and the video signal obtained in the n-th horizontal scan from the vertical synchronization pulse is f(Q, n). As shown in FIG. 6, it is shaped into a binary pulse video signal, f(Q, n)
The amplitude-modulated ultrasonic signal is applied to an ultrasonic transducer in an ultrasonic light 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 signal within the ultrasonic light modulator is u(x, n).
, u(1 x, n). Ultrasonic light modulator 5a is 5b
The length of the ultrasonic wave in the traveling direction is made longer than that of the ultrasonic wave, and the time for the ultrasonic signal u(x, n) to reach the laser beam east is one horizontal scanning time longer than the time for u(1×, n) to reach the same point. It will be delayed by 63.5 French s. Therefore, the ultrasonic signals that overlap within the laser beam are u(x, n) and u(1×, n11). 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,
Considering that n), u(1×, n+1) are moving at the ultrasonic velocity v, only the diffracted light generated by the ultrasonic signal is detected by the spatial light intensity filter 6 and photoelectrically converted. By doing this, the following correlation output c(t,i
) is known to be obtained. Here d is Caesar
Represents the width of Koto.

g(x, n) represents the envelope of u(x, n), and f(Q,
It is obtained by linearly converting Q of n) to x.

In this {1} formula, g (x, i) ± g (1 ×, i + 1)
…If we apply the relationship {2}, then c(t,i)
represents the autocorrelation function of g(x,i) or f(Q,i).

Both c(t, n) and f(Q, n) are functions of the number of horizontal scans n. Therefore, c(t,n) becomes f(Q,n
), 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 the formula '1} using an optical correlator, '1' is used to avoid the square characteristic during photoelectric conversion in the photoelectric converter 7.
It is necessary to make g(x, i) in the equation a binary real number function, and specifically, the input image should be limited to a black and white binary image as in the conventional device, or it should be set as in the present invention, which will be described later. A video signal pulsing circuit with a threshold value is required. The above is the configuration and operating principle of the conventional 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 in the performance and operation aspects of the conventional device as listed above. The present invention compensates for the drawbacks of the image correlation device described above and further adds a new device. The purpose is to make it a practical and functional device.

In other words, the system removes restrictions on the size of input images and allows input of all images, including moving images that can be input with a television camera, and is equipped with two television cameras for inputting images. An object of the present invention is to provide an image correlation device capable of displaying a cross-correlation image between two different images.

Furthermore, for simultaneous comparison of input and output images, one of the input images and a correlated image are simultaneously displayed on the left and right sides of the center of the receiver screen.

To achieve this objective, we used a pair of television cameras capable of synchronized horizontal scanning, and added two systems of synchronized pulse separation circuits and video signal pulsing circuits to convert composite video signals into binary pulse video signals. did. Furthermore, 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 is placed on the light incident surface of the image pickup tube in the television camera. Furthermore, a single horizontal scanning image is extracted from the bidirectional horizontal scanning image. Added horizontal synchronization selection circuit. Next, this invention will be specifically explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of a television image correlation apparatus for displaying a cross-correlation image between two television images according to the present invention.

The correlation calculation operation is similar to the operating principle of the conventional device. 1st
The configuration and operating principle of the figure will be explained as follows while comparing it with FIG. 4, which describes the configuration of a conventional device. In the present invention, the television camera 14, the synchronous pulse separation circuit 10, and the video signal pulsing circuit 9 shown in FIG.
13b, and their respective binary pulse video signals are output from a pair of video signal pulsing circuits 9a, gb. In addition, television cameras 14a and 14b
In the optical system parts (Aa, Ab in FIG. 1), light intensity filters 22a, b as shown in FIG. 2 were similarly arranged in both parts. FIG. 2 is an enlarged view of the optical system parts Aa and Ab in FIG. ing. FIG. 3 shows the shape of the light intensity filters 22a and 22b when viewed from all directions of the optical axis of the lens system 21 of the television camera. In FIG. 3, the rectangle in the center of the figure is a gate through which light enters. The short side of this opening is the image pickup tube 2
3, and the aperture width corresponds to the horizontal scanning direction of image pickup tube 23.
The scanning length is determined to be 1/Z. Further, this light intensity filter 22 is arranged at the center of the light entrance window of the image pickup tube 23. Next, in the present invention, the television cameras 14a and 14b are simultaneously horizontally scanned by the output signal of the bidirectional sweep oscillator 15, and the television cameras operate so that the horizontal scanning directions are opposite to each other. That is, when the television camera 14a starts horizontal scanning from left to right, the television camera 14b starts horizontal scanning from right to left. As a result, the shape of the ultrasonic optical modulator 5a in the operating principle of the correlator described above is enlarged, and the x-axis inverted video signal and the non-inverted signal are superimposed using the ultrasonic propagation delay within the modulator. It's no longer necessary. The television cameras 14a, 14b
Since the video signals of are always inverted video signals, cross-correlation calculation can be performed by simply superimposing these two signals.
For this reason, the ultrasonic light modulators 5a and 5b have the same shape and are oriented in opposite directions only in the ultrasonic propagation direction. Next, in the present invention, the set threshold values of the video signal pulsing circuits 9a and 9b are fixed to an intermediate value of the black and white level values of the video signals obtained by the television cameras 14a and 14b, and furthermore, the input and output of these video signal pulsing circuits is A horizontal synchronization selection circuit 2 which takes one of the signals as an input signal is newly added. The function of this horizontal synchronization selection circuit 2 is to sample the video signal of the input image obtained by bidirectional horizontal scanning with an analog gate circuit that operates in synchronization with the horizontal synchronization pulse, and to select the image signal obtained by unidirectional horizontal scanning. It extracts only the video signal, and the uncorrelated input image displayed on the receiver is
Duplication of flipped images due to bidirectional horizontal scanning can be avoided. The input image displayed on the image receiver can be switched between two input images or a pulse image converted into a black and white binary image by switching with the switch No. 17 in FIG. In addition, horizontal synchronization pulse delay circuit 1
The delay time of 1' was changed from 1'Zk average synchronization time of 32rs used in the conventional device to 16ms of 1'Yuki Hiraoka period. FIG. 7 shows that based on these results, one input image and a correlated image can be displayed on the screen of the image receptor 16 with the center as the border.

FIGS. 7a and 7b show composite video signals of two images to be cross-correlated, obtained by the television cameras 14a and 14b. Figures c and d are the ultrasonic optical modulator 5a mentioned above,
5b represents an ultrasonic signal traveling inside the cell. Figure e shows the relationship between the correlator output signal and the delayed synchronization pulse. Since the centers of the ultrasonic signals in c and d of the figure overlap with each other about 32 seconds later than the horizontal synchronization pulse, the correlation output C(0) at this time temporally overlaps with the synchronization signal of the television camera. Therefore, as shown in FIG. 5E, a delay of 16 ms is given to the synchronizing pulse so that the correlation output signal and the input image signal exist between the delayed horizontal synchronizing pulses. Therefore, if the signal shown in the figure e is displayed on a receiver, one of the input images and the cross-correlation image can be simultaneously observed on the left and right sides of the center of the screen. The present invention has the above configuration, and if the images can be photographed by the television cameras 14a and 14b, the horizontal scanning cross-correlation image of those images is combined with the input image or one of its black and white binary images. This has the effect of allowing simultaneous comparative observation on the same picture tube.

Furthermore, since there are no restrictions on the size of the input image or the position of the photographed image, it is also possible to photograph and input a moving object. In this case, the television cameras 14a, 14
It is also possible to record the results of long-term shooting with b fixed on a video tape, etc., and use the video signal as an input signal for the device, or to record the correlation results as they are, which will reduce the operating speed of the TV system. Effects such as time-lapse photography and high-speed photography can also be expected. Furthermore, the input image can be enlarged or reduced by replacing the lens system 21 of the television camera, which is effective for more accurate measurements.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is a common internal configuration diagram of parts a and AB in FIG. 1, FIG. 3 is a front view of the light intensity filter 22, and FIG. 4 is a conventional FIG. 5 is a diagram showing bidirectional horizontal scanning of an input image, FIG. 6 is a diagram showing a timing chart of signals of a conventional device, and FIG. 7 is a diagram showing a timing chart of signals of an embodiment of the present invention. Figure shown. la, lb are sine wave oscillators, 2 is a horizontal synchronization selection circuit, 3
a, 3b are broadband amplifiers, 4 is a Caesar light source, 5a, 5
b is an ultrasonic light modulator, 6 is a spatial light intensity filter, 7 is a photoelectric converter, 8 is a video signal amplifier, 9a, 9b are video signal pulsing circuits, 10a, 10b are synchronous pulse separation circuits, 11 is a Horizontal sync pulse delay circuit, 12 is a mixer, 13
a and 13b are input images, 14a and 14b are television cameras, 15 is a bidirectional oscillator, 16 is an image receiver, 17 is a switch, 18 to 20 are missing numbers, 21 is a television camera lens system, 22 is a light intensity filter; 23 is an image pickup tube;
101 is a correlator, 102 is a Fourier transform optical system, A indicates the location of a light intensity filter, ULMs 5a and 5b are ultrasonic light modulators, f(Q,i) and f(Q,i11) are C(t) indicates the input image signal, and C(t) indicates the correlation output. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. An image correlation device for displaying a cross-correlation image between black and white binary converted images of two input images 13a and 13b; first and second television cameras 14a, 14 which perform bidirectional horizontal scanning of input images and reverse scanning in synchronization with each other;
b; first and second synchronization pulse separation circuits 10a and 10b that separate the respective output signals of the cameras 14a and 14b into respective video signals and synchronization pulse signals; and; converting the respective video signals into respective binary signals. first and second video signal pulsing circuits 9a and 9b for converting into signals; receiving two pulsed image signals output from the respective video signal pulsing circuits 9a and 9b and generating their cross-correlation signals; Correlator 1 outputs
01; In order to simultaneously display the output image of the correlator and the output image of the first or second television camera on the same receiver, the synchronization pulse signal separated by the synchronization pulse separation circuit is delayed. a horizontal synchronizing pulse delay circuit 11 that outputs a delayed signal; a selection circuit 17 that selects one of the input and output signals of each of the first and second video signal pulsing circuits 9a and 9b; a horizontal synchronization selection circuit 2 for receiving the output signal of the circuit 17 and the output signal of the horizontal synchronization pulse delay circuit 11 and extracting only the video signal obtained by unidirectional horizontal scanning; the correlator 101; A television image correlation device comprising a mixer 12 that receives the output signal of the horizontal synchronization selection circuit 2, the delayed signal, and the output signal of the horizontal synchronization selection circuit 2, and outputs a composite video signal to a television receiver. 2. The correlator 101 includes a pair of amplitude modulated sine wave oscillators 1a and 1b; Wideband amplifiers 3a and 3b which use the output signal of the sine wave oscillator as an input signal; Ultrasonic wave using the output signal of the amplifier as an input signal a Fourier transform optical system 102 having a pair of ultrasonic modulators 5a and 5b whose propagation directions are opposite to each other; a laser 4 that is a light source of the optical system; and a photodetection filter 6 that detects output light of the optical system. The television image correlation device according to claim 1, comprising: and a photoelectric converter 7 that photoelectrically converts the output light. 3. The first and second television cameras 14a, 14b are
Approximately at the center of the front surface of each image pickup tube, there is a
Optical filters 22a, 22b having an aperture width of 2 or less
A television image correlation device according to claim 1, characterized in that the television image correlation device comprises: