JPS6033355B2 - image correlation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image correlation apparatus that obtains a horizontal scanning direction autocorrelation image of a television image in real time.

Conventionally, image correlation devices input images from a television camera and perform correlation calculation processing. 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.

○} Since only correlated images can be displayed on the receiver screen,
It is difficult to compare 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 left and right quarters of the correlation image display receiver screen, that is, half of the entire screen, are not used for display due to the operating principle.

{3' In order to repeatedly and continuously perform finite interval correlation calculations, the length of the input image in the horizontal scanning direction must be 1/sa below the horizontal synchronization time after conversion to a binary pulse video signal, due to the operating principle. 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) Since the correlation value at each point of the correlation image is expressed by luminance, the accuracy of quantitative display is poor due to the nonlinear voltage versus luminance characteristic 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 land. 3 "One-shot construction method of image correlation device using ultrasonic light modulator and 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. 4, an input image 13 to be autocorrelated is generated by a bidirectional sweep oscillator 15, and a television camera 14 performs bidirectional horizontal scanning using a triangular wave of 7.87 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 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 pulsed image signal is sent to and compared with a set threshold 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 are arranged so that the directions of the ultrasonic waves are opposite to each other, and the light transmitted therethrough is converged by a beam to form a rope point on the focal plane. A spatial light intensity filter 6 is arranged at 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. The synchronizing pulses separated by the synchronizing pulse separating circuit 10 are sent to the horizontal synchronizing time delay circuit 11, subjected to a time delay, and then added to the lag 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. The delay time of the horizontal synchronization time delay circuit 11 is set to about 1/of the horizontal synchronization time.
2.32-s, and if the composite video signal is configured into an image by the receiver 16, the autocorrelation image of the input image 13 can be displayed at 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 between video signals in a vertical relationship is roughly obtained by approximating the autocorrelation function. As shown in Fig. 5, the input image is a binary image P(Q,
8), 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. 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 in the ultrasonic light modulators 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 is delayed by 63.5 seconds. Therefore, the ultrasonic signals that overlap within the laser beam are u(x, n) and u(1×, 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,
Considering that n), u(1×, n11) 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 transmitted. By converting, the following correlation output c(t,i
) is known to be obtained. C (t, i): g (X-Vt, i) g (-X 10 Vt, i 11) blood
...[1} 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 '1} formula, g(x, i)≠g(1×,i+1)...{
2}, then 4 C(t,i)=Kamigameg(X■W,i)g(X0vt,i
) Ship...'3', and c(t, i) becomes g(also, i), i.e. f(Q,
i) represents the autocorrelation function of i).

Both c(t, n) and f(q, n) are functions in the horizontal scanning circuit 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 value of the signal is limited to 1'2 of the horizontal synchronization time. Furthermore, when executing the above equation (1) using an optical correlator, g(x, i) in the m equation is made into a binary real number function in order to avoid the square characteristic during photoelectric conversion in the photoelectric converter 7. Specifically, it is necessary to limit the input image to a black and white binary image as in the conventional device, or to use a video signal pulsing circuit with a set function value.The above is the configuration and operating principle of the conventional device. be.

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 image 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 above (1) to {4}.The present invention does not compensate for the drawbacks of the image correlation device described above, but also adds a new device. The purpose is to make the device more practical and functional.

That is, it is an object of the present invention to provide an image correlation device that removes restrictions on the size of input images and can input all images including moving images that can be input with a television camera.

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.

Additionally, a horizontal synchronization selection circuit is added to extract a single horizontal scan image from a bidirectional horizontal scan image. 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 for displaying a horizontal scanning direction correlation image of the present invention.

The image 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, a light intensity filter 22 as shown in FIG. 2, which is an enlarged view of section A, is arranged in the optical system portion of the television camera 14 (FIG. 1A) used in the conventional device. FIG. 2 shows that a light intensity filter 22 is placed between the lens system 21 and the image pickup tube 23 of a television camera. FIG. 3 shows the shape of this light intensity filter 22 when viewed from the optical axis direction of the lens system 21 of the television camera. In FIG. 3, the rectangle in the center of the figure is an aperture through which light enters. The short side of this opening coincides with the horizontal scanning direction of the imaging tube 23, and the width of the opening is determined to be 1/2 the horizontal scanning length of the imaging tube 23. 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 setting value of the video signal pulsing circuit 9, which is a component of the conventional device, is fixed to the intermediate value of the black and white level values of the video signal obtained by the television camera 14, and the input and output signals of the video signal pulsing circuit 9 are A horizontal synchronization selection circuit 2 that receives either of these inputs 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. The uncorrelated input image that is displayed on the receiver can avoid the duplication of flipped images due to bidirectional horizontal scanning. The input image displayed on the image receptor can be either a pulse image converted into a black and white binary image or an input image by switching the input image using the sliding door shown in FIG. Also, the delay time of the horizontal synchronization time delay circuit 11 was changed from the 1'2 horizontal synchronization time of 32 peaks used in the conventional device to the 1'7K horizontal synchronization time of 16ms. FIG. 7 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. FIG. 7a shows a video signal obtained by bidirectional horizontal scanning of an image to be autocorrelated, and FIG.
represents the ultrasound signal in b. Figure d shows the output of the mixer 12. The ultrasonic signal is delayed by 63.5 rs inside the ultrasonic light modulator 5 shown in FIG.
It takes 32 seconds to overlap with the internal ultrasonic signal of
The center of the correlation output appears at the same time as the horizontal synchronization pulse, as shown in Figure d. Therefore, the sweep width of the video signal is reduced to 1/Zk by the light intensity filter 22 of the television camera 14.
If the horizontal scanning length is set, the video signal and the correlation signal will not overlap in time. Therefore, as shown in the figure, by delaying the horizontal synchronization pulse by 1/°C horizontal synchronization time 16 seconds,
It becomes possible to display the input image and its correlated image on the left and right sides of the center of the image receptor screen. The present invention has the above-described configuration, and has the effect that, as long as the image can be photographed by the television camera 14, the horizontal scanning direction autocorrelation image of the image can be simultaneously compared and observed on the same picture tube as the input image.

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 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 can be enlarged or reduced by replacing the lens system of the television camera 14, 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 diagram showing the internal structure of the section A in FIG.
2, FIG. 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. 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, 9 is a video signal pulsing circuit, 10' is a synchronization pulse separation circuit, and 11 is a horizontal synchronization time Delay circuit, 12 is a mixer, 13 is an input image, 14 is a television camera, 15 is a bidirectional sweep oscillator, 16 is an image receiver, 17 is a changeover switch, numbers 18 to 201 are missing, 21 is a television camera lens system, 22 23 is a light intensity filter, 23 is an image pickup tube, 10 is an image pickup device, 101 is a correlator, 102 is a Fourier transform optical system, A is the position where the light intensity filter is placed, ULM5a and ULM5b are ultrasonic waves. Light modulators, f(Q, i) and f(Q, i+1) indicate input image signals. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. The input image 13 is an image for displaying a pulse image obtained by converting the input image 13 into a black and white binary image and an autocorrelation image of the pulse image on the left and right sides with the center of the same screen of the image receptor as the border. A correlation device; an imaging device 100 that includes a lens system 21 and an image pickup tube 23 and outputs a composite video signal obtained by bidirectionally horizontally scanning the input image; 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 synchronization pulse 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 it with a predetermined threshold value; a correlator 101 for outputting a signal; and a horizontal synchronization time delay circuit for delaying the synchronization signal output from the synchronization pulse separation circuit in order to display the autocorrelation image on either the left or right half of the screen of the receiver. 11; horizontal synchronization selection for selecting only the signal obtained by unidirectional scanning of the horizontal scanning by the delayed synchronization signal among the pulsed video signals obtained by converting the separated video signal; circuit 2
and; receiving and mixing the separated video signal or pulse image signal output from the horizontal synchronization selection circuit, the autocorrelation signal output from the correlator, and the synchronization signal output from the horizontal synchronization time delay circuit; , and a mixer 12 that provides the mixed output to an image 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 converts the amount of output light. 3 An image correlation device for displaying the input image 13 or a pulse image obtained by converting the input image 13 into black and white binary values, and an autocorrelation image of the pulse image to the left and right with the center of the same screen of the image receptor serving as a border; a lens; system 21 and an image pickup tube 23,
an imaging device 100 that outputs a composite video signal obtained by bidirectionally horizontally scanning the input image; and limiting light passing through the lens system to 1/2 or less of the scanning length at approximately the center of the imaging tube. a light intensity filter 22 having an aperture width; a synchronization pulse separation circuit 10 that separates the composite video signal into a video signal and a synchronization signal; and a binary pulse by comparing the separated video signal with a predetermined threshold value. a video signal pulsing circuit 9 that converts it into a video signal; a correlator 101 that receives the pulsed image signal output from the video signal pulsing circuit and outputs an autocorrelation signal; and a correlator 101 that outputs an autocorrelation signal; a horizontal synchronization time delay circuit 11 for delaying the synchronization signal output from the synchronization pulse separation circuit for display on either the left or right half of the screen; the delayed synchronization signal of the separated video signal; a horizontal synchronization selection circuit 2 that selects only the signal obtained by one-way scanning of the horizontal scanning; a separated video signal or pulsed image signal output from the horizontal synchronization selection circuit; and the correlator. and a mixer 12 that receives and mixes the autocorrelation signal output from the horizontal synchronization time delay circuit and the synchronization signal output from the horizontal synchronization time delay circuit, and provides the mixed output to a receiver. .