JPS6031677A - Device for optically calculating correlation - Google Patents

Abstract

PURPOSE:To perform operation for obtaining congruent transformation-type correlation in a speed approximated real time, by constituting a calculating device with two space light modulation tubes, a laser source, two lenses and a detector. CONSTITUTION:A pattern 21 of an aggregate of bacteria at a time of t0 is magnified by a lens 1, and a pattern (g) is read and stored in an optoelectric crystal 22c of a space light modulation tube 22. The state (h) upon expiring of 50msec is read and stored also in said tube 22 at a distance 22b away from the pattern (g). Parallel beams from a laser source 30 are projected onto the crystal 22c through half-mirrors 24 and 23, and reflecting light including said information (g) and (h) is taken out. The light which is reflected by the half-mirror 23 is Fourier-transformed by a lens 2. Its pattern is read and stored in an optoelectric crystal 25c of a space light modulation tube 25. This information is read by the parallel laser beams which are supplied by the light source 30 through half- mirrors 24 and 26 and a total reflection mirror 27, and the light including this information if Fourier-transformed by a lens 3, thereby being focused on a detector 28.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to an apparatus for optically calculating the correlation between two images.

(Description of Prior Art) For example, by determining the correlation between the density distribution of a large number of bacteria, sperm, etc., at a certain time to, and the density distribution at tl after a certain time elapsed from to, You can understand the state of your body's movements.

If the correlation between the density distribution of the aggregate at to and the density distribution at tl is large, the movement of the aggregate is small, and conversely, if the correlation is small, it means that it is moving violently.

Furthermore, by changing the time interval, for example, after 1Qmsec or 50m5ec from the original state, by taking the correlation value for each time, it is possible to examine how much exercise is being performed.

A joint transform correlation method is used to obtain the cross-correlation of objects by optical calculation.

The principle of this joint transformation type correlation method can be explained by referring to Fig. 1 and calculating the correlation between the distribution pattern of points at time to as g (X) and the pattern h (x) at tl after a certain time has elapsed. I will briefly explain about.

First, as shown in Figure 1 (A), the pattern of the distribution of points at time 1 (, g (
=2 b ; g (x) and h (x) so that they do not overlap) are recorded on film I and developed. The recording can be easily realized by moving the film at time to by 2b at time tl.

The transmittance distribution characteristics of the film I obtained in this way are as follows when focusing on an arbitrary one-dimensional image of the pattern, the center of the image g (X) is b, and the center of the image h (x) is -b
If we set the midpoint as the origin, it is expressed as U+ (X)=g (x-b) +h (x+b).

Next, as shown in FIG. 1(B), the image on film I is subjected to Fourier transformation and exposed on film 2.

The thus obtained film (2) represents the magnitude of the frequency component of the image of the film (2), with the coordinate axis representing the frequency and the degree a representing the magnitude of the component.

As a result, the density distribution of film ■ can be obtained by using the Fourier transform of g as G, the Fourier transform of h as H, and the transition constant as follows: U2 (f)=lG-exp (-j2πf-b)+H
-exp (j2πf-b)12 =G-G'+H-H'10G-H'exp(-j4yrf-b)+G' -H
exp (j4πf-b) where G' is G, H' is H
The conjugate complex number of the film ■
When a parallel laser beam is irradiated perpendicular to , and the transmitted light is subjected to Fourier transformation using a lens, the pattern becomes the image g on film I.
Autocorrelation image g*g (x) of (x).

The autocorrelation image h*h(x) of h (x) and the cross-correlation image g* of the image obtained by moving g (x) and h (x) by a distance of 2b.
h (x 2b), and the cross-correlation image h*g (x+2b) of images obtained by moving h (x) and g (X) by a distance of -2b
), resulting in an image U3 (X).

03 (X)=ff*g (x)+h*h (X) 10g
th(x 2b) +h*g (x+2b) Thus the autocorrelation g*g(x) and h*h (X)
is X=O, cross correlation g*h is x=2 b, h+kg
It appears as a bright spot at x=-2b.

If the brightness of g*g (x) and h*h (x) is 1, then the brightness of g*h (x 2b) and h*g (x+2b) is smaller than 1 and appears darker than them, and g If the concentration distributions of and h are similar, it is close to 1<, and if they are not similar, it is close to O.

The light intensity at coordinate 2b and/or coordinate -2b point of such an image is detected by a detector, and if it is bright, the correlation is large;
The results show that the correlation is small when it is dark.

A joint transformation type correlation can be obtained in the above manner.

However, as mentioned above, since the development step is required, there is a problem that it takes a long time to obtain the result.

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to provide an optical correlation calculation device that can perform the above-described operations at a speed close to real time.

(Description of Configuration) In order to achieve the above object, the apparatus for optically calculating correlation according to the present invention inputs object images to be correlated at appropriate time intervals and stores them in different locations. 1 spatial light modulation tube, a laser light source that generates collimated light for reading out the stored image, a lens that Fourier transforms the read out image, and a lens into which the Fourier transformed image is written. a second spatial light modulation tube, a collimated laser light source for reading out an image of the second spatial light modulation tube, and a lens for inverse Fourier transforming the read out image;
and means for detecting an image that has been subjected to inverse Fourier transform.

(Description of Examples) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

Referring first to FIG. 2, the basic configuration and operating principle of the spatial light modulation tube used in the apparatus according to the present invention will be briefly explained.

Photocathode 22. The input incoherent image 4 incident on a is photoelectrically converted, and the photoelectrons are transferred to the microchannel plate 2.
2b, it is multiplied several thousand times. The multiplied electrons adhere to the surface of the electro-optic crystal 22C or emit secondary electrons, thereby forming a charge pattern on the surface of the electro-optic crystal 22C.

Therefore, the electric field across the crystal is large in areas where charges exist and is almost zero in other areas, resulting in local differences in refractive index in the crystal due to the electro-optic effect.

Therefore, when the crystal 22c is irradiated with a reading laser beam from the laser light source 30 via the half mirror 23, the laser beam is modulated due to the difference in refractive index within the crystal 22c.

As a result, a coherent image 5 having input incoherent image information is obtained.

FIG. 3 is a block diagram showing an embodiment of an apparatus for optically calculating correlation according to the present invention.

FIG. 4 is a waveform diagram for explaining the operation of the device.

This will be explained using an example of determining the correlation between patterns of bacterial aggregation.

The pattern 21 of the bacterial aggregation at time t is magnified by the lens 1 and the electro-optic crystal 22C of the spatial light modulation tube 22 is
Write and store pattern g. At this time, the controller 31 outputs a write pulse (2) to operate the spatial light modulation tube 22.

Then, the state after 5'0 m5 ec has elapsed is similarly written and stored in the spatial light modulation tube 22 at a distance g and 2b. For the above-mentioned write storage, a deflection signal (2) is applied from the controller 31 together with a write pulse (2) to the deflection coil 22d (see FIG. 4), and is written at a position separated by 2b as shown in FIG. 3.

The collimated laser beam from the laser light source 30 passes through the half mirror 24 and the half mirror 23 to the electro-optic crystal 22.
The reflected light is incident on C, and the reflected light containing the information on g and h is taken out.

The light reflected by the half mirror 23 is Fourier transformed by the lens 2, and the Fourier transform is written and stored in the electro-optic crystal 25C of the spatial light modulation tube 25.

Pulse 2 shown in FIG. 4 is a pulse supplied from the controller 31 to the spatial light modulation tube 25 for this writing.

Next, the signal shown in FIG. 4 is given from the controller 31, and the information in the spatial light modulation tube 22 is erased to prepare for the next writing.

Write and record 1 on the electro-optic crystal 25C of the spatial light modulation tube 25
．． The collected information is read out by a collimated laser beam supplied from the laser light source 30 via the /SS rougher 24, the total reflection mirror 27, and the nof mirror 26. The read light containing the information is Fourier-transformed by the lens 3 and is imaged onto a detector 28 consisting of an image sensor.

The outputs caused by the autocorrelation values h*h, g*g and cross-correlation values h*g, g*h formed on the detector 28 are sent to the comparator 29.
are compared and displayed on the display 40.

The display 40 receives the pulse (2) from the controller 31 and displays the degree of correlation between g and h.

Thereafter, the information in the spatial light modulation tube 25 is erased by the signals (1) and (2) from the controller 31.

(Explanation of effects) With the simple operation described above, it is possible to examine the movement of a large number of aggregates of bacteria, sperm, etc., and this has great effects in the fields of medicine and biology.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram for explaining the principle of the joint transformation type correlation method. FIG. 2 is a schematic diagram for explaining the configuration and operation of a spatial light modulation tube used in the apparatus according to the present invention. FIG. 3 is a block diagram showing an embodiment of an apparatus for optically calculating correlation according to the present invention. FIG. 4 is a waveform diagram for explaining the operation of the device. 112+ 3... Lens 4... Input image 5... Coherent output image 21... Input image 22... Spatial light modulation tube 22a... Photocathode 22b... Microchannel plate 22c...
Electro-optic crystal 22d...deflection coil 23,? , 26... Half mirror 25... Spatial light modulation tube 25c... Electro-optic crystal 27... Total reflection mirror 28... Detector 29... Comparator 30... Laser light source 31...・Controller patent applicant Hamamatsu Photonics Co., Ltd. Agent Patent attorney Inoro Juga Figure 1 (B) (C)

Claims (2)

[Claims] (1) A first spatial light modulation tube into which object images to be correlated are input at appropriate time intervals and stored in different locations, and a collimated light for reading out the stored images. A laser light source that generates a laser beam, a lens that Fourier transforms the readout image, a second spatial light modulation tube into which the Fourier transformed image is written, and a collimated lens that reads out the image of the second spatial light modulation tube. A device for optically calculating a correlation, comprising a laser light source, a lens for inverse Fourier transform of the read image, and means for detecting the inverse Fourier transform image. (2) Optically calculating the correlation according to claim 1, wherein the laser light sources that generate the light for reading the images stored by the first and second spatial light modulation tubes are a common laser light source. device to do.