JPS6034316B2 - Image correlation device between optical images and television images - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image correlation device between an optical image and a television image, which obtains a horizontal scanning cross-correlation image between the television image and the optical image in real time.

Conventionally, image correlation devices input images from a television camera and perform correlation calculation processing. 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. (2) Since the finite interval correlation calculation is repeatedly and continuously performed, the 1/4 left and right sides of the screen of the correlation image display receiver, that is, half of the entire screen, are not used for display due to the principle of operation.

'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/sa 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} There are still improvements to be made for use as a practical device, such as a new information processing method that utilizes the spatial operations unique to electro-optic correlators and a simplified device configuration.

The authors first published the journal of the Society of Electronics and Communication Engineers in March 1979.
Month Vol. 621A M. 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. 5 shows a schematic diagram of the configuration of a conventional device. The outline of the purpose of creating this device was to focus on the fact that the video output signal of a commonly used television camera has a repetition period and frequency band appropriate for the 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 The goal is to obtain correlated images. In the apparatus shown in FIG. 5, an input image 13 to be autocorrelated is generated by a bidirectional oscillator 19, and a television camera 14 performs bidirectional horizontal scanning using a triangular wave of 7.87 arc days 2.
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 river. 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 are arranged so that the directions of the ultrasonic waves are opposite to each other, and the light transmitted through the modulators is converged by a lens to form a dot on the focal plane. A photodetection filter 6 is arranged on the focal plane, and the light passing through this filter is photoelectrically converted by a photoelectric converter 7 to become an output current of the optical correlator. Note that the principle of optical correlation calculation will be explained in detail later. Now, the synchronization pulse separated by the synchronization pulse separation circuit 10' is sent to the horizontal synchronization time delay circuit 11 and subjected to a time delay, and then the binary code mixer 12
added to. 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. The delay time of the horizontal synchronization time delay circuit 11 is approximately 1 of the horizontal synchronization time.
/2,32ms, and the composite video signal is transmitted to the receiver 16.
If the input image 13 is configured as an image, the autocorrelation image of the input image 13 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 integrated by a lens to produce images that are adjacent to each other, that is, the screen. In the above example, the cross-correlation function between video signals in a vertical relationship is roughly obtained by approximating the auto-correlation function. As shown in Figure 6, the input image is a binary image P(Q,
3), and let f(Q, n) be the video signal obtained in the n-th horizontal scan from the vertical synchronization pulse. As shown in FIG. 7, 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 waves are opposite to each other, the ultrasonic signals in the ultrasonic light modulators are u(x, n),
It can be written as u(1 x, 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 horizontal scanning time 6 times longer than the time when (1 x, n) reaches the same time
It is delayed by 3.5 mountain s. 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 the bran calculation,
The converging action of the lens represents an integral operation. Also u(x, n
), u(1×, n+1) are moving at the ultrasonic velocity v, so only the diffracted light generated by the ultrasonic signal can be detected by the spatial light intensity filter 6 and photoelectrically converted. As a result, the following correlation output c(t,i) is obtained as a current value.
is known to be obtained. Mountain C(t,i)=climb'g(X-W,i)g(1x+vt
, i+1) Autumn...m Here, d represents the width of Caesar 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 [Equation 11, g (x, i) ≠ g (1 ×, i + 1)
…If we apply the relationship {2}, then LC(t,i)=Kageug(X−Re,i)g(x×vt,
i) The gunwale... becomes glue, and c(t, i) becomes g(x, i), that is, 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. However, as a condition to execute the milk formula and obtain independent c(t, n) for each n, there must be a no-signal part of the same length before and after the video signal. The maximum length of is limited to 1/2 of the horizontal synchronization time. In addition, when executing the formula '1-' using an optical correlator, in order to avoid the square characteristic during photoelectric conversion in the photoelectric converter 7, '1}
It is necessary to make g(x, i) in the formula a binary real number function, and specifically, the input image is limited to a black and white binary image as in the slave device, or as in the present invention described later. A video signal pulsing circuit with set threshold values 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, regarding the performance and operation of the conventional device, there are problems [1] to '4] listed 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.

In other words, the restriction on the size of TV input images is removed, all images including moving images that can be input with a TV camera are input, and cross-correlation images with optical images input and arranged in a correlator are created. An object of the present invention is to provide an image correlation device that obtains.

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, a light intensity filter was placed on the light incident surface of the image pickup tube in the television camera in order to form a no-signal portion in the video signal regardless of the size or movement of the input image.

In addition, the two-way horizontal scanning of the television camera was changed to unidirectional horizontal scanning, and the correlator was equipped with one amplitude-modulated sine wave oscillator, one broadband amplifier, and one ultrasonic optical modulator, and the ultrasonic waves were removed. Instead of a light modulator, a light transmission type one-dimensional image can be input and arranged. Next, this invention will be specifically explained with reference to the drawings. FIG. 1 is a block diagram of an embodiment of an image correlation apparatus according to the present invention that displays a cross-correlation image between an optical image and a television image simultaneously with an input image. The optical correlation calculation operation is the same as the conventional device, but
In the present invention, the two ultrasonic light modulators in the conventional device are combined into one, and an optical image is placed in place of the removed ultrasonic light modulator. As a result, the TV input image signal and the optical image 1
A horizontal scanning cross-correlation signal Cp(t) obtained by the correlator 101 is expressed by the following equation. d Cp(t)=J "sf(X-vt)g(X)dX・■.
...'41 In Equation 4, g(x) is a function indicating the integral value of the optical image 18 in the y-axis direction perpendicular to the x-axis and the optical axis.

That is, the optical image 18 is transformed into a two-dimensional function P(x,
y), g(x) is given by the following equation. g(x
)='miP(x,y)dy...[51 Therefore,
Information meaningful in the y-axis direction of the optical image 18 is not used in the cross-correlation calculation with the television input image.

Therefore, a one-dimensional grating or the like having a periodic distribution in the x-axis direction is used for the optical image 18. Next, if we compare equation {4} with equation [3}, which was used to explain the operating principle of the conventional device, we can see that the shift (delay) speed of the two signals to be correlated is 1/2 that of the conventional device. It can be seen that

Furthermore, in order to display the correlation output signal simultaneously with the television input image on the screen of the image receiver 16, it is necessary to keep the signal time within 32 seconds. Therefore, the length of the binary pulse video signal applied to the correlator 101 is limited to 16 seconds or less, and the length of the optical image in the x-axis direction is 16 seconds in terms of time based on the ultrasonic propagation velocity v.
〃Limited to a value below ss. Therefore, in the present invention, the optical system part of the television camera 14 (
A light intensity filter 22 as shown in FIG. 3, which is an enlarged view of section A in FIG. 1A), was arranged. FIG. 3 shows that the light intensity filter 22 is arranged between the television camera lens system 21 and the image pickup tube 23. The shape of this light intensity filter 22 viewed from the direction of the light beam of the television camera lens system 21 is shown in FIG. 4, 22a. In FIG. 3 22a, the rectangle at the center of the circle is an opening through which light enters. The short side of this opening □ coincides with the horizontal scanning direction of the image pickup tube 23, and the opening □
The width is determined by the 1' horizontal scanning length of the pseudo-image tube 23.
Further, this light intensity filter 22a is arranged at the center of the light entrance window of the bran image tube 23. Next, in the present invention, the above-mentioned '
As is clear from equation 4), the video signal used for correlation calculation is f
(x, i), so x
There is no need to create an axis-inverted video signal f(1×, i+1).
The television camera 14 thus performs a unidirectional horizontal scanning operation. Further, as for the input image to be displayed simultaneously with the correlation image on the screen of the receiver, either the input image or its black and white binary pulse image can be selected by operating the switch 17. FIG. 8 shows that based on these results, the input image and the correlated image can be displayed on the screen of the image receptor 16 with the center as the border. Figure a shows a composite video signal with a time width of 16 ms obtained by the television camera 14, and Figure b shows an ultrasonic signal that has undergone amplitude modulation with a binary pulse video signal obtained from the video signal. It shows how it moves inside the acoustic wave light modulator 5. Figure c
shows an example of an optical image placed within the correlator 101. This image is created and arranged as appropriate in accordance with the input image and its characteristics to be detected. 10 shows the result of mixing the two-signal cross-correlation signal Cp(t,i) shown in FIGS. 4B and 3C with the input image signal and the delayed synchronization pulse.
If this mixed signal is displayed on the screen of the receiver, the input image 1
3 or a pulse image obtained by converting it into black and white binary values, and the cross-correlation image appear on the left and right sides of the same screen with the center as a border. FIG. 2 is a block diagram of an embodiment of an image correlation device according to the present invention for displaying a cross-correlation image between an optical image and a television image at the center of a receiver screen.

In the present invention, since the image receptor screen is dedicated to the cross-correlation image, the time width limit of the correlation signal is within about 64 seconds. Therefore, the time width of the binary pulse video signal that can be input to the correlator 101 in FIG. The one shown in was used. The width of the entrance in the horizontal scanning direction of the light intensity filter 22b in the figure is 1/2 the horizontal scanning length. Further, the time conversion value of the ultrasonic propagation velocity v in the x-axis direction of the optical image was set to be 32rs or less. In addition to these, the mixer 12 generates two signals, a correlation signal and a delayed synchronization signal.
It is the same as the invention described above except that it is changed to one that mixes signals and the switch is removed. FIG. 9 shows how to obtain a cross-correlation between a television image signal and an optical image.
Figure a shows a composite video signal with a time width of 32 seconds obtained by the television camera 14, and Figure b shows an ultrasonic signal that has undergone amplitude modulation with a binary pulse video signal obtained from the video signal. It shows movement inside the acoustic wave light modulator 5. Figure c
shows an example of an optical image, and d in the same figure shows the result of mixing the cross-correlation signal Cp(t, i) of the above-mentioned b and c with the delayed synchronization signal. When this mixed signal is displayed on a receiver screen, a cross-correlation image of the input image 13 and the optical image 18 is obtained. The present invention has the above configuration, and if the image can be captured by the television camera 14, a cross-correlation image in the horizontal scanning direction between that image and the optical image 18 created in advance is displayed on the same picture tube as the input image. This has the effect of allowing simultaneous or only correlated images to be observed at the center of the picture tube.

If the optical image 18 is created in the form of a lattice, it is possible to detect the spatial period in the television image that corresponds to the lattice spacing.Also, it is possible to detect a television image of the same shape using an optical image of a specific shape, which is a so-called optimal filter. Applying the principle of etching has the effect of enabling high-speed pattern matching processing. Also,
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 moving objects. In this case, it is also possible to fix the TV camera 14 and record the results of long-term photography on a videotape or the like, and use the video signal as an input signal for the device, or to use the correlation results as they are as a green screen. Effects such as time-lapse photography and high-speed photography within the operating speed of the television system can also be expected. Furthermore, the input image is transmitted to the television camera 14.
By replacing the lens system, input can be enlarged or reduced, which is effective for more accurate measurements.

[Brief explanation of drawings]

1 and 2 are diagrams showing an embodiment of the present invention, FIG. 3 is an internal configuration diagram of part A in FIGS. 1 and 2, and FIG. 4 is a front view of the light intensity filter 22, and FIG. Figure 5 shows a conventional example, and Figure 6 shows a conventional example.
7 is a diagram showing bidirectional horizontal scanning of an image, FIG. 7 is a diagram showing a signal timing chart of a conventional device, and FIGS. 8 and 9 are diagrams showing signal timing charts of an embodiment of the present invention. 1, la, lb are sine wave oscillators, 2 is a missing number, 3, 3a,
3b is a broadband amplifier, 4 is a Caesar light source, 5, 5a, 5
b is an ultrasonic optical modulator, 6 is a photodetection filter, 7 is an optical turtle converter, 8 is a video signal amplifier, 9 is a video signal pulsing circuit, 1 is a synchronization pulse separation circuit, 11 is a horizontal synchronization time delay circuit, 12 is a 2-signal mixer, 13 is an input image, 14 is a television camera, 15 is a 3-signal mixer, 16 is a receiver, 17
18 is an optical image; 19 is a bidirectional sweep oscillator; 21 is a television camera lens system; 22 is a bidirectional sweep oscillator;
22a and 22b are light intensity filters, 23 is an image pickup tube, and 10
1 is a correlator, 102 is a Fourier transform optical system, A is a location where a light intensity filter is placed, ULM5, UL
M5a and ULM5b are ultrasonic optical modulators, f(Q,i),
f(Q, i+1) is the input image signal, C(t), Cp(t
) indicates a correlation signal. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. An input image 13 or a pulse image obtained by converting it into black and white binary, and a cross-correlation image between the pulse image and the optical image 18, to the left and right with the center of the same screen of the image receptor as the border. An image correlation device for displaying a television camera 14 that includes a lens system 21 and an image pickup tube 23 and outputs a composite video signal obtained by horizontally scanning the input image in a single direction; a light intensity filter 22 having an aperture width that limits the transmitted light to 1/4 or less of the scanning length at approximately the center of the image pickup tube; a separation circuit 10 that separates the composite video signal into a video signal and a synchronization signal; and; a video signal pulsing circuit 9 that converts the separated video signal into a binary pulsed video signal by comparing it with a predetermined threshold; and receiving a pulsed image signal output from the video signal pulsing circuit. a correlator 101 that outputs a cross-correlation signal with the optical image;
a delay circuit 11 for delaying a synchronization signal output from the separation circuit in order to display the cross-correlation image on either the left or right half of the screen of the receiver; the separated video signal or pulse image signal; An optical image characterized by comprising a mixer 15 that receives and mixes the cross-correlation signal output from the correlator and the synchronization signal output from the delay circuit, and provides the mixed output to a receiver. and image correlation device with television images. 2 Sine wave oscillator 1 in which the correlator 101 can modulate amplitude
a broadband amplifier 3 whose input signal is the output signal of the sine wave oscillator; a Fourier transform optical system 102 having an ultrasonic light modulator 5 whose input signal is the output signal of the amplifier; and a light source of the optical system. The optical system according to claim 1, comprising: a laser 4; a photodetection filter 6 for detecting the optical output of the optical system; and a photoelectric converter 7 for photoelectrically converting the output light. Image correlation device between images and television images. 3 Image correlation for displaying the input image 13 or a pulse image obtained by converting it into black and white binary, and a cross-correlation image between the pulse image and the optical image 18 to the left and right with the center of the same screen of the image receptor as the border The apparatus includes: a television camera 14 that includes a lens system 21 and an image pickup tube 23 and outputs a composite video signal obtained by horizontally scanning the input image in a single direction; a light intensity filter 22 having an aperture width limited to 1/2 or less of the scanning length at approximately the center of the tube; a separation circuit 10 for separating the composite video signal into a video signal and a synchronization signal; a video signal pulsing circuit 9 that converts the video signal into a binary pulsed video signal by comparing the video signal with a predetermined threshold; a correlator 101 that outputs a cross-correlation signal with;
a delay circuit 11 for delaying a synchronization signal output from the separation circuit in order to display the cross-correlation image at the center of the receiver screen; a cross-correlation signal output from the correlator and an output from the delay circuit; a mixer 1 that receives and mixes the synchronization signals to be transmitted and provides the mixed output to the receiver;
2. An image correlation device for optical images and television images, characterized by comprising: 4 Sine wave oscillator 1 in which the correlator 101 can modulate amplitude
a wideband amplifier 3 whose input signal is the output signal of the sine wave oscillator; a Fourier transform optical system 102 having an ultrasonic optical modulator 5 whose input signal is the output signal of the amplifier; and a light source of the optical system. The optical system according to claim 3, characterized in that the optical system comprises: a certain laser 4; a photodetection filter 6 that detects the optical output of the optical system; and a photoelectric converter 7 that photoelectrically converts the output light. Image correlation device between target images and television images.