JPH09204235A - Optical correlator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make optical correlation quantitative. SOLUTION: This device has a spatial optical modulator 12 for inputting object images to be correlated at suitable time intervals and recording the subtracted images of respective object images, laser light source 18 for generating light made parallel for reading the subtracted image recorded in this spatial optical modulator 12, photodetector 28 for photodetecting the read image of light and outputting an electric signal corresponding to the intensity of received light, and correlation display for displaying the levels of correlation among the respective object images to be correlated based on the electric signal outputted from this photodetector 28. Thus, since the degree of optical correlation between the respective object images is converted to the electric signal by the photodetector 28 and this can be quantitatively shown on the display like an ammeter, the degree of level of optical correlation can be effectively grasped while being extremely simplified.

Description

Detailed Description of the Invention

[0001]

This invention relates to the correlation between two images,
The present invention relates to a device that optically calculates.

[0002]

2. Description of the Related Art For example, by deriving a correlation between a density distribution of a large number of bacteria, sperm, etc. at a certain time t0 and a density distribution at a certain time t1 from the time t0, the movement of the aggregate is obtained. You can grasp the situation of.

That is, the density distribution of the aggregate at time t0,
If the correlation with the density distribution at the time t1 is large, the motion of the aggregate is small, and conversely, if the correlation is small, it means that the motion is intense. Further, by changing the time interval for obtaining the information of the density distribution, it is possible to grasp how much exercise is performed by obtaining the correlation value for each time.

In order to obtain the cross-correlation of such an object,
Conventionally, an optical operation such as a correlation operation by a Vander Light type match filter and a congruential conversion type correlation method has been used. As a means for realizing the latter congruential conversion type correlation method, there is an apparatus for optically calculating the correlation as disclosed in, for example, JP-A-60-31677.

[0005]

[Problems to be Solved by the Invention] In the former correlation calculation,
There is a problem that real-time calculation cannot be performed because there is no device that takes a Fourier transform hologram and has a sufficient response speed.

Further, Japanese Patent Laid-Open No. 60-
The device disclosed in Japanese Patent No. 31677 discloses an optical addressing spatial light modulator called MSLM, which uses an electro-optic crystal as a light modulating material and a combination of a photocathode and a micro channel plate as an addressing material.
Two units are used for input and for recording the power spectrum, but since the response speed of this spatial light modulator is as slow as several hundred ms, it is complicated to match the timing of these operations. There is.

Further, in the above apparatus, autocorrelation or cross-correlation in the same pattern appears in the correlation output, which causes noise. To avoid this, the focal length of the lens for Fourier transform is increased, or There is a problem that the arrangement of input patterns must be restricted. Furthermore, the method of obtaining the correlation using only the subtraction without using the Fourier transform has a problem that the tolerance for the positional deviation of the input pattern is very small.

Furthermore, in the case of performing subtraction between the object images to be correlated, the reference object image or the referenced object image is added and written in the spatial light modulator, and then the referenced object or the referenced object is subtracted and written. However, at this time, the contour portion of the object image often remains without being subtracted, which causes a problem that an error due to the contour portion occurs in the value of the correlation due to the optical output. .

As described above, in the conventional optical correlation device,
Although there are inherent problems as described above due to the unique configuration and function of each device, the degree of correlation (correlation magnitude) of each object image to be correlated is determined by any conventional device. , It is difficult to grasp quantitatively and easily with a simple structure.

That is, when one of the object images to be correlated is subtracted from the other object image, these subtracted images are obtained as a two-dimensional image. The "degree" of the correlation, that is, the magnitude of the correlation is subtracted. It can be understood only by the subjectivity of the person who visually observes the image.

This situation is described in "OPTICAL ENGI
The optical information processing technology disclosed in “NEERING” magazine (Vol. 17, No. 4) is no different, and even if the difference between the images of the object images can be grasped on the image,
It is difficult to quantitatively measure the magnitude of the degree of correlation.

The present invention has been made in view of the above problems of the prior art, and is an apparatus capable of optically calculating the correlation between two images and quantitatively measuring the magnitude of the correlation of each object image. Is realized with a simple configuration and easy control.

Further, according to the present invention, real-time subtraction can be performed at a sufficient response speed, and even when two spatial light modulators for input and power spectrum recording are used, their timings need to be strictly adjusted. It is an object of the present invention to provide an optical correlation device that does not have the above.

Further, according to the present invention, when performing Fourier transform,
It is possible to suppress noise due to autocorrelation and cross-correlation in the correlation output without increasing the focal length of the lens or limiting the arrangement of the input pattern, and when performing correlation without using Fourier transform. On the other hand, it is an object of the present invention to provide an optical correlator having a large tolerance for the deviation of the input pattern.

Further, according to the present invention, when subtracting between the object images having the correlation, it is possible to prevent the contour portion of the object image from remaining without being subtracted, and an error occurs in the correlation value. It is an object of the present invention to provide an optical correlation device that suppresses this.

[0016]

According to a first aspect of the invention, a spatial light modulator for inputting object images to be correlated at appropriate time intervals, subtracting each object image, and recording a subtracted image, A laser light source that generates a laser beam for reading the subtracted image recorded in the spatial light modulator, and an electric signal that receives the image of the light read from the spatial modulator and that corresponds to the intensity of the received light. And a correlation indicator that displays the magnitude of the correlation of each object image to be correlated based on the electrical signal output from this photodetector, and an optical system having The above-mentioned object is achieved by the optical correlation device.

In this optical correlator, a filter for low-pass filtering may be arranged in the optical path of the subtraction image.

Further, in the optical correlation device, the optical writing section of the spatial light modulator may be divided into at least two split optical writing sections which are independently operated. Furthermore, the spatial light modulator may have a memory function,
It may be a ferroelectric liquid crystal spatial light modulator.

A second invention is a spatial modulator for inputting object images to be correlated at an appropriate time interval and converting each object image into coherent information, and a coherent output from this spatial light modulator. A laser light source for generating a laser beam for reading various information, a lens for Fourier-transforming the read image, and subtracting and recording each Fourier-transformed pattern of coherent information based on each object image. Spatial light modulator, a laser light source for generating a laser beam for reading out the subtraction pattern recorded in the second spatial light modulator, a read light beam, and a laser beam source according to the intensity of the received light beam. An optical detector comprising a photodetector that outputs an electric signal, and a correlation indicator that displays the magnitude of the correlation of each object image to be correlated based on the electric signal output from the photodetector. The related device is to achieve the above object.

Further, in the optical correlation device of the second invention,
A filter that performs low-pass filtering may be arranged in the optical path of the subtraction pattern. In addition, the second spatial light modulator may be divided into at least two split write sections, each of which has a Fourier transform optical write section that operates independently.

Further, in the optical correlation device of the second invention, the second spatial light modulator may have a memory function or may be a ferroelectric liquid crystal spatial light modulator.

[0022]

In the first aspect of the invention, the subtraction image of the object image input at an appropriate time interval is generated by the spatial light modulator, read by laser light, and detected by the photodetector. Here, since the photodetector outputs an electric signal according to the intensity of the read light, the correlation indicator can quantitatively display the magnitude of the correlation. In this way, since the optical correlation can be calculated and the degree thereof can be quantified, it is possible to realize a practical optical correlation device that has a simple structure, yet is easy to control.

When the optical writing section is divided into two or more, the optical correlation can be quantitatively calculated in real time at a sufficient response speed.

In the second aspect of the invention, in addition to being able to quantitatively grasp the magnitude of the correlation of each object image, the coherent information based on each object image is subtracted in the Fourier pattern after being Fourier transformed to obtain the correlation. Therefore, the noise due to the autocorrelation in the correlation output and the cross-correlation in the same pattern when the correlation calculation is performed on the object image before the Fourier transform is eliminated, and therefore the focal length of the lens to be Fourier-transformed is increased or the input There is no need to limit the arrangement of patterns.

In the second and seventh aspects, since the filter for performing the low-pass filtering is arranged in the optical path of the subtraction image or the subtraction pattern, the contour portion of the object image remaining without being subtracted is removed. Thus, the error in the correlation output can be eliminated.

Further, as described in claims 3 and 8, the optical writing section of the spatial light modulator or the second spatial light modulator is a plurality of divided optical writing sections which are independently operated, so that the cost is low. Therefore, a high response speed can be obtained.

Furthermore, since the spatial light modulator has a memory function in claim 4 or 9, it is not necessary to read the written image at a high speed, and the object image is sequentially updated each time. This is convenient for reading and correlating.

In the fifth and tenth aspects, since the spatial light modulator is a ferroelectric liquid crystal spatial light modulator, it is possible to operate at a high response speed, and when the optical writing section is divided, During optical writing to one divisional writing section, there is no possibility that light enters another divisional writing section due to stray light from the lens system or the like to a portion which should not be written and raises the dark level.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

In a device (hereinafter referred to as a correlation device) 10 for calculating an optical correlation according to the first embodiment of the first invention, a transparent electrode (details will be described later) on the side of an optical writing section is equally divided into two. Ferroelectric liquid crystal spatial light modulator (hereinafter FLC-SLM) 1
2, an image forming unit 16 arranged on the optical writing side of the FLC-SLM 12 to form an image of the writing light separately on the divided optical writing unit, and a parallel for reading the image stored in the FLC-SLM 12. A laser light source 18 for generating a converted laser beam and a condenser lens 2 for condensing a read image
An optical system 21 including 1A and 21B, and a condenser lens 21
A photodetector 28 including photodiodes 28A and 28B that detect the light collected by A and 21B and output a current according to the intensity, and an ammeter 30 that detects and displays the output current of the photodiodes 28A and 28B. It is configured with. Reference numeral 32 in FIG. 1 indicates an object to be correlated, for example, an aggregate of a large number of bacteria, sperms, and the like.

As shown in FIG. 2, the FLC-SLM 12 has a ferroelectric liquid crystal layer 36 disposed between a pair of alignment layers 34A and 34B, and a ferroelectric liquid crystal layer 36 from the writing light incident side. The optical fiber plate 60 arranged in this order, the writing side transparent electrode 38, the amorphous silicon (hereinafter a-Si) layer 40 as an address material, the dielectric mirror 42, and the ferroelectric liquid crystal layer 36 from the reading side. The transparent electrode 44 on the readout side, the glass layer 46, and the antireflection film 48, which are arranged in this order, are laminated.

The writing side transparent electrode 38 is divided into two on the optical fiber plate 60 as shown in FIG. 3 to form divided transparent electrodes 38A and 38B. These divided transparent electrodes 38A, 38B have conductors 39A, 3
9B are connected to each other, and a positive electric field pulse or a negative electric field pulse is independently applied to the ferroelectric liquid crystal layer 36 via the divided transparent electrodes 38A and 38B by the operating circuit 52. .

The image forming means 16 includes a pretreatment tube 56 having a microchannel plate (hereinafter referred to as MCP) 54, and a photocathode 56 on an end face of the pretreatment tube 56 on the light input side.
A lens 58 for forming an image of the object 32 on A, and an output phosphor screen 56B at the rear end of the pretreatment tube 56,
An optical fiber plate 60 is connected to the writing-side transparent electrode 38 of the LC-SLM 12. Note that reference numeral 62 in FIG. 1 denotes an erasing LED for erasing a light image by irradiating the photocathode 56A.

A photocathode 56A is provided in the pretreatment tube 56.
From the output fluorescent screen 56B toward the electron lens system 56
C, the deflection electrode 56D, and the MCP 54 are arranged in this order.

The laser light source 18 is a He-Ne laser 18
A, a spatial filter 18B, a collimator lens 18C for converting the laser light passing through the spatial filter 18B into parallel rays, and a mirror 18 for reflecting the parallel rays.
F and the parallel light reflected by the mirror 18D.
-A half mirror 18E for irradiating the transparent electrode 48 on the reading side of the SLM 12 with the half mirror 18E.

Condensing lenses 21A and 2 in the optical system 21
1B is arranged in parallel at positions corresponding to the divided transparent electrodes 38A and 38B, and the condensing lens 21A condenses the read light corresponding to the divided transparent electrode 38A and condenses the read light corresponding to the divided transparent electrode 38B into the condensing lens 21B. Are focused on the photodiodes 28A and 28B in the photodetector 28, respectively.

Next, the operation of the apparatus of the above embodiment will be described.

An image of the object 32, which is an aggregate of a large number of bacteria or sperms, etc., is taken by a lens 58 from a pretreatment tube 56.
An image is formed on the photocathode 56A in FIG. The photoelectrons output from the photocathode 56A pass through the electron lens system 56C and the deflection electrode 56D, and the MCP 54
And is multiplied by the MCP 54 to illuminate the output fluorescent screen 56B. When the object 32 is a bacterium or the like, since the emitted fluorescence or the like is weak light, the light intensity is amplified by the MCP in this way.

The optical image whose intensity is amplified in the pretreatment tube 56 is formed on the light receiving surface of the FLC-SLM 12 via the optical fiber plate 60.

In the optical writing section of the FLC-SLM 12, the writing side transparent electrode 38 is divided into two as shown in FIG. 3 to form divided transparent electrodes 38A and 38B. The divided transparent electrodes 38A and 38B are independently operated by the operation circuit 52. Further, the ferroelectric liquid crystal layer 36 does not perform light modulation unless the corresponding divided transparent electrodes 38A and 38B are activated. Therefore, depending on whether or not a voltage is applied to the divided transparent electrodes 38A and 38B, the light modulation in the ferroelectric liquid crystal layer 36 is independently performed in the portions corresponding to the divided transparent electrodes 38A and 38B. become.

First, at time T = t0, the image of the object 32 is divided by the deflection electrode 56D of the pretreatment tube 56 into the divided transparent electrodes 38.
Shake to form an image on the A side. At this time, the operating circuit 52 controls so that the voltage is applied only to the divided transparent electrode 38A and is not applied to the divided transparent electrode 38B. Further, a voltage is applied to the divided transparent electrode 38 so as to add an image.

Therefore, the writing is performed so that the images are added only on the side of the divided transparent electrode 38A.

In the ferroelectric liquid crystal layer 36, the ON state is switched in the area irradiated with the writing light in proportion to the incident light intensity. Since the ferroelectric liquid crystal layer 36 has a memory function, the object image is stored in the portion corresponding to the divided transparent electrode 38A, and the voltage applied to the divided transparent electrode 38A is removed.

Next, at time T = t0 + t, the object image after t seconds is written in the portion of the FLC-SLM 12 corresponding to the divided transparent electrode 38A. At this time, by the operation circuit 52,
A voltage is applied to the split transparent electrode 38A so as to subtract the image.

Next, a voltage reverse to the above is applied to the deflecting electrode 56D so that an object image is formed on the divided transparent electrode 38B. At this time, a voltage is applied to the divided transparent electrode 38B so as to add an image. Therefore, the subtracted image is written in the portion of the ferroelectric liquid crystal layer 36 corresponding to the divided transparent electrode 38A, and the divided transparent electrode 3 is also written.
New writing will be performed in the portion corresponding to 8B.

Split transparent electrode 38A of FLC-SLM 12
The subtraction image recorded in the area corresponding to is read by parallel light from the laser light source 18, and is input to the photodiode 28 via the lens 21A. The photodiode 28A generates a photocurrent corresponding to the received light intensity and outputs it to the ammeter 30.

FLC-S corresponding to the divided transparent electrode 38A.
In the subtraction image written in the LM 12, when the overlap between the object image at time t0 and the object image at time t0 + t is small (that is, the correlation is small), there are few portions of the same pattern, and thus the intensity of the read light is large. Therefore, in the ammeter 30,
When the output current of the photodiode 28A is detected to be large, it means that the correlation between the images of the two objects is small, and the movement of the bacteria or sperm aggregate, which is the object 32, is large.

On the contrary, when the output current of the photodiode 28A corresponding to the light intensity of the subtracted image is small, the correlation is large and the movement of the aggregate of bacteria and sperm is small. The degree of correlation can be grasped quantitatively.

The operating circuit 52 allows the FLC-SLM 12
There are a plurality of types of modes for operating the divided transparent electrodes 38A and 38B. In FIG. 4, a new object image is subtracted from the object image corresponding to one divided transparent electrode, the same new object image is written in the other divided transparent electrode, and then the subtracted image is written in one divided transparent electrode. The process of erasing, writing the next new object image, and subtracting with the same new image on the other divided transparent electrode side is repeated, and divided transparent electrodes 38A, 38B
3 is a correlation calculation time chart for sequentially correlating object images.

First, a region corresponding to both of the divided transparent electrodes 38A and 38B by the erasing LED 62 (hereinafter referred to as ITO).
1. Erase the written image of ITO2).

Next, a voltage is applied to the divided transparent electrode 38A, and an object image (pattern 1) is formed by the pretreatment tube 56.
Is swung to the side of the divided transparent electrode 38A to write the corresponding ITO1. At this time, no voltage is applied to the divided transparent electrode 38B side.

Next, while the written image (pattern 1) on the side of the divided transparent electrode 38A is stored, a pulse of a voltage for subtraction is applied to the divided transparent electrode 38A and a pulse for addition is applied to 38B, and T1 is applied to ITO1 and ITO2. = T0 + t A new object image (pattern 2) is written. At this time, IT
The subtraction image (pattern 1-2) written in O1 is read by the reading light, is input to the photodiode 28A through the condenser lens 21A, and is read by the ammeter 30 as described above.
The output is displayed as the correlation magnitude.

Next, the subtracted image of ITO1 (pattern 1-
2) is erased, a voltage is applied to the divided transparent electrodes 38A and 38B so that ITO1 is added and ITO2 is subtracted, and a new object image (pattern 3) of T = t0 + 2t is shaken to subtract the added image. The image is updated, and the subtracted image {pattern n- (n = 1)} is read each time, and the correlation is taken.

Therefore, the correlation of the objects can be obtained at a high speed by sequentially performing the correlation at the rewriting interval of the object images of ITO1 and ITO2, for example, about 100 μsec.

In the above embodiment, in order to reduce the erasing voltage of the FLC-SLM when erasing the recorded object image, the erasing LED 62 and the deflection electrode 56 of the pretreatment tube 56.
By the operation of D, the light is uniformly applied to the optical writing section of the FLC-SLM 12. The compensation voltage pulse at the time of optical writing at that time is under the condition that the FLC-SLM 12 is not turned on in the dark state, as shown in FIG.

The present invention is not limited to the above, and as shown in FIG. 6, erasing may be performed by an erasing voltage without using the erasing light.

At the operation timing as shown in FIG. 6, the erase L
When the image is erased only by the erase voltage applied to the divided transparent electrodes without using the ED 62, the correlation interval can be further shortened as compared with the case where the erase LED is used, and therefore the object image is extremely fast. Correlation can also be calculated for movement.

In the above embodiment, the writing side transparent electrode 38 is used.
Is divided into two parts on the left and right sides in the figure. In this case, for example, as shown in FIG. 7A, the readout side transparent electrode 44 is not divided, or
As shown in (B), the write-side transparent electrode 38 is equally divided into two, and the read-side transparent electrode 44 is equally divided into two in a direction orthogonal to this dividing direction to form divided transparent electrodes 44A,
It may be set to 44B. In the case of FIG. 7 (B),
By allowing the divided transparent electrodes 44A and 44B to operate independently, the ferroelectric liquid crystal layer 36 can be divided into four parts and used. Further, each or one of the writing-side transparent electrode 38 and the reading-side transparent electrode 44 may be divided into three or more, and in the case of division, the division is not necessarily equal.

In the above-mentioned embodiment, the input object image is deflected by the pretreatment tube 56 having the deflection electrode 56D. This input object image deflection means, for example, as shown in FIG. The optical element 64 may be used. 8, reference numeral 66 is an image intensifier (II) arranged on the light incident side of the FLC-SLM 12, 68 is an ultrasonic wave generator, 70 is an ultrasonic wave generator 68, and FLC-SLM1.
2 and I. Reference numeral 72 denotes a controller for operating in synchronization with I66, and 72 denotes an imaging lens.

Further, as shown in FIG. 9, the input object image deflecting means similarly includes the FLC-SLM 12 and the I.D. The movable mirror 76 may be operated in synchronization with I66. FIG.
The reference numeral indicates the controller of the movable mirror 76.

Next, an apparatus for optically calculating a correlation according to the first embodiment of the second invention will be described.

In this embodiment, the same parts as those of the first embodiment are designated by the same reference numerals,
The description is omitted.

As shown in FIG. 10, a device 80 for calculating an optical correlation (hereinafter referred to as a correlation device) is a FLC-S.
LM13 (transparent electrode is not divided) and this FL
An image forming unit 17 arranged on the optical writing side of the C-SLM 13 for forming an image of the writing light on the optical writing unit, and FLC-
A laser light source 19 for generating a collimated laser light for reading out the image stored in the SLM 13, a lens 20 for performing a Fourier transform on the read image, and a lens 20 for writing the Fourier transformed image. FLC-S of 2
The LM 22, a reading optical system 24 for guiding the collimated light for reading the image of the second FLC-SLM 22 from the laser light source 19, and an inverse Fourier transform of the image read from the second FLC-SLM 22. Lens 26 for
And a photodetector 29 including a photodiode for detecting an image of light subjected to the inverse Fourier transform by the lens 26, and an ammeter 30 for detecting and displaying an electric signal output of the photodetector 29. There is.

The FLC-SLM 13 is different from the FLC-SLM 12 in the embodiment of the first invention shown in FIG.
The other structure is the same as that of the FLC-SLM 12 except that the transparent electrode 38 is not divided. Further, the image forming means 17 has an image intensifier (hereinafter referred to as II) 74 instead of the pretreatment tube 56 as compared with the embodiment of FIG.
Is different from the coupling means 16 only in that

I. I74 is a photocathode 74A, an electron lens system 74B, an MCP 74C, and an output phosphor screen 47.
And D in this order from the light input side. Similar to the embodiment of FIG. The output phosphor screen of I74 and the FLC-SLM 13 are the optical fiber plate 6
0.

The second FLC-SLM 22 is a FLC-S.
The configuration is similar to that of the LM 13, and the pair of alignment layers 22A,
The ferroelectric liquid crystal layer 22C arranged between the two 22B, the writing side transparent electrode 22D arranged in this order from the writing light incident side to the ferroelectric liquid crystal layer 22C, and amorphous silicon (hereinafter referred to as a- The read side transparent electrode 22G arranged in this order from the Si) layer 22E, the dielectric mirror 22F, and the ferroelectric liquid crystal layer 22C to the read side.
The glass layer 22H and the antireflection film 22I are laminated.

The laser light source 19 is obtained by rewriting the mirror 18D of the laser light source 18 in the embodiment of FIG. 1 into a half mirror 18F.

The reading optical system 24 is a half mirror 18.
The total reflection mirror 24A that reflects the light that has passed through F, and the parallel light reflected by the total reflection mirror 24A are used as the second FLC.
-The read light of the SLM 22 is provided with a half mirror 24B for irradiating the read light. FIG.
Reference numeral 22J of 1 indicates an erasing LED for the second FLC-SLM 22.

Next, the operation of the apparatus of the above embodiment will be described with reference to FIG. FIG. 11 is an operation timing chart of the embodiment of FIG.

First, the erasing LEDs 62, 22J
The images recorded on the LC-SLM 13 and the second FLC-SLM 22 are erased.

Next, I. Multiplied by I57, FLC-S
An image (pattern 1) of the object 32 recorded in the LM 13 at T = t0 is read by parallel light from the laser light source 18, Fourier transform is performed in the lens 20, and the power spectrum of the read power spectrum is output to the second FLC-SLM 22. Write.
Here, the response speed of the FLC-SLM 13 is 100 μs.
Because of the following, the SLM for writing the power spectrum is also made to be the ferroelectric liquid crystal SLM correspondingly.

Next, the erasing LED 62 is used to display the FLC-
The image recorded on the SLM 13 is erased, and time T = t0 + t
The object image (pattern 2) in step 3 is written in the FLC-SLM 13. The image written in the FLC-SLM 13 is read out in the same manner as described above and, after being Fourier-transformed by the lens 20, its power spectrum is the second FLC-SLM 22.
Is written to.

At this time, in the second FLC-SLM 22,
The operation circuit 53 controls so that the subtraction writing is performed. This second FLC-SLM 22 already has T = t.
Since the power spectrum of the object image at 0 o'clock is written, subtraction of the power spectra of the two object images is performed,
This is recorded in the second FLC-SLM 22.

The reading of the second FLC-SLM 22 is performed by the reading optical system 24 in the same manner as usual, and the reading light is subjected to the inverse Fourier transform in the lens 26,
It is input to the photodetector 29. The photodetector 29 generates a photocurrent corresponding to the received light intensity and outputs it to the ammeter 30.

Fourier-transformed in the lens 20,
When the two images of the power spectrum written in the second FLC-SLM 22 have a large overlap, that is, a large correlation, the intensity of the light subjected to the inverse Fourier transform by the lens 26 is low.

Therefore, when the output current of the photodiode 28 is detected to be small (the received light intensity of the photodiode 28 is small) in the ammeter 30, it means that the correlation between the images of the two objects is large, which is the object 32. Bacteria and sperm aggregates will move less.

On the contrary, when the output current of the photodiode 28 is detected to be large (that is, the received light intensity of the photodiode 28 is large), the correlation is small and the movement of the bacterial or sperm aggregate is large.

Next, a second embodiment of the second invention shown in FIG. 12 will be described.

The correlation device 90 of the second embodiment is shown in FIG.
2nd FLC-SLM22
Instead of, the divided transparent electrode 23 is divided into two equal parts on the writing side and independently operated by an operation circuit (not shown).
The second FLC-SLM 23, which is A and 23B, is provided, and the lens 20 for Fourier transform and the half mirror 1 are provided.
8E, an acousto-optic element 64 (driving circuit is not shown) is arranged, and a lens 26 for inverse Fourier transform is provided.
Are two lenses 26A and 26B corresponding to the divided transparent electrodes 23A and 23B.
Photodiodes 28A and 28B are provided corresponding to 26B. The other structure is the same as that of the embodiment shown in FIG.

Next, the operation of this embodiment will be described with reference to the operation timing chart of FIG.

First, by using the erasing LEDs 62, 22J, the F
After erasing the images recorded in the LC-SLM 13 and the second FLC-SLM 23, the image of the object 32 (pattern 1) is written in the FLC-SLM 13 at time T = t0.

Next, the object image stored in the FLC-SLM 13 is read out by parallel light and Fourier-transformed by the lens 20, and the power spectrum of the object is read by the second FLC.
-Write to SLM 23. At this time, the image is deflected by the acousto-optic device 64 so as to be input to the divided transparent electrode 23A. Therefore, it is written in the region (hereinafter referred to as ITO1) corresponding to the divided transparent electrode 23A of the second FLC-SLM 23.

The Fourier transform pattern written in the ITO1 is stored as it is, and the LED
The recorded image of the LC-SLM 13 is erased, and time T = t0 + t
The image (pattern 2) of the object 32 at FLC-SLM13
, And write the Fourier transform pattern to the acousto-optic device 6
4 is deflected to write in the regions (ITO1, ITO2) corresponding to the divided transparent electrodes 23A and 23B.

At this time, the writing on the ITO1 side is performed by subtracting the image by the operation circuit. Also, ITO
In 2, write so as to add images. Therefore, ITO
In 1, the subtracted pattern of the two images is recorded,
The second pattern will be stored in ITO2.

Next, the read optical system 24 is used to make ITO.
The subtraction Fourier transform pattern recorded in
The data is read out via A and the electric signal corresponding to the light intensity is output from the photodiode 28A. Photodiode 28
The relationship between the output signal and the correlation is the same as in the first embodiment.

Then, after erasing the recorded image, FLC
The object image (pattern 3) at time T = t0 + 2t is written in the -SLM 13.

The third image written in the FLC-SLM 13 is read out and Fourier-transformed in the same manner as described above, and then written to the ITO1 where the recording is erased beforehand so as to add the image, and further written in the ITO2. Write to subtract the image. Therefore, in this state, when the subtraction pattern recorded on the ITO 2 is read out through the lens 26B, the correlation of the object 32 can be obtained by the output intensity.

In this way, the divided transparent electrodes 23 are sequentially formed.
By writing the subtraction pattern in A and 23B, the movement of the object can be grasped at each time t.

In the operation timing chart shown in FIG. 13 or 11, an erasing L is added to the optical write section of the FLC-SLM 13 and the second FLC-SLMs 22 and 23.
By irradiating light uniformly with the EDs 62 and 22J, the erasing voltage of these FLC-SLMs at the time of erasing is lowered, but in these embodiments, as in the first invention, as shown in FIG. The recorded image may be erased only by the erasing voltage without using the erasing light at the operation timing as shown.

Next, the third aspect of the second invention shown in FIG.
An example will be described.

The correlator 100 of the third embodiment is shown in FIG.
0 in the first embodiment of the FLC-SLM 13 and the second F
The function of the LC-SLM22 is the same as that of one FL.
This is achieved by the C-SLM 15.

The transparent electrode on the optical writing side of the FLC-SLM 15 is composed of two split transparent electrodes 15 which are independently operated.
A, 15B, and I.D. From I74 through lens 59,
The object image written on the side of the divided transparent electrode 15A is read by parallel light from the half mirror 18E of the laser light source 19A, and the read laser light is read by the mirrors 25A and 25A.
B, 25C, 25D and the Fourier transform lens 20 are used to write as a Fourier transform pattern on the divided transparent electrode 15B.

The written Fourier transform pattern is
The light is read by the read light introduced through the half mirror 18G added to the laser light source 19 in the embodiment of FIG. 10, and is input to the photodetector 29 through the inverse Fourier transform lens 26.

The operation of the third embodiment is the same as that of the first embodiment, so the description thereof will be omitted.

In each of the above embodiments, the Fourier transform is not performed, and simple subtraction between the object images for correlation is performed,
Further, although incoherent-coherent conversion is performed by the FLC-SLM and a Fourier pattern is further subtracted by a Fourier transform lens, the contour portion of the object image often remains without being subtracted at this time. Occur. Therefore, there is a problem that an error occurs in the correlation value due to the light output from the contour portion.

On the other hand, as shown in FIG. 16, for example, a low-pass filter (aperture) 80 is arranged on the Fourier transform surface of the lens 20 for the read light of the FLC-SLM and the Fourier transform, and a high frequency component is provided. Is cut and is focused on the photodetector 29 by the lens 82. By doing so, the contour portion remaining in the subtraction output between the object images is erased, so that an error caused in the value of the correlation of the optical output by the contour portion (the value indicated by the ammeter 30) can be prevented. it can.

In the case of the embodiment shown in FIG. 10, the inverse Fourier transform lens 2 is used as shown in FIG.
If the conversion surface of 6 is provided with the low-pass filter 80, an error can be similarly prevented.

[0098]

As described above, according to the present invention, the optical correlation of each object image is converted into an electric signal by a photodetector, and this can be quantitatively shown by a display such as an ammeter. Therefore, the degree of the optical correlation can be grasped effectively and extremely easily. Therefore, it is possible to realize a highly practical optical correlation device capable of efficiently measuring the movement of an object such as bacteria or sperm in real time.

[Brief description of drawings]

FIG. 1 is an optical system diagram viewed from above showing a first embodiment of an apparatus for calculating an optical correlation according to the first invention.

FIG. 2 is an enlarged cross-sectional view showing a main part of a FLC-SLM in the example.

FIG. 3 is a plan view showing divided transparent electrodes in the FLC-SLM of the same example.

FIG. 4 is a timing chart showing a correlation calculation process by the optical correlation calculation apparatus of the embodiment.

FIG. 5 is a timing chart showing a state of an erase compensating voltage pulse in the FLC-SLM of the example.

FIG. 6 is a timing chart when the image erasing method is changed in the same embodiment.

FIG. 7 is a roadside perspective view showing a modified example of division of the transparent electrode in the FLC-SLM.

FIG. 8 is a block diagram showing a main part of second and third embodiments of an apparatus for calculating an optical correlation.

FIG. 9 is a block diagram showing a main part of second and third embodiments of an apparatus for calculating an optical correlation.

FIG. 10 is an optical system diagram showing a first embodiment of an apparatus for calculating an optical correlation according to the second invention.

FIG. 11 is a timing chart showing a correlation calculation process performed by the optical correlation calculation device of the embodiment.

FIG. 12 is an optical system diagram showing a second embodiment of the second invention.

FIG. 13 is a timing chart showing a process of calculating an optical correlation according to the second embodiment.

FIG. 14 is a timing chart when the image erasing method in the second embodiment is changed.

FIG. 15 is an optical system diagram showing a third embodiment of the second invention.

FIG. 16 is an optical system diagram showing a main part of a modified example of the embodiments of the first invention and the second invention.

FIG. 17 is an optical system diagram showing a main part of a modified example of the embodiments of the first invention and the second invention.

[Explanation of symbols]

10, 80, 90, 100 ... Device for calculating optical correlation, 12, 13 ... Ferroelectric liquid crystal spatial light modulator (FLC-
SLM), 14 ... Optical fiber plate, 15A, 15
B, 23A, 23B, 38A, 38B, 44A, 44B
... Divided transparent electrodes, 16, 17 ... Imaging means, 18, 19 ...
Laser light source, 21 ... Optical system, 22, 23 ... Second FLC
-SLM, 22C, 36 ... Ferroelectric liquid crystal layer, 24 ... Readout optical system, 26, 26A, 26B ... Lens, 28, 2
9 ... Photodetector, 30 ... Ammeter, 32 ... Object, 38 ... Writing side transparent electrode, 44 ... Read side transparent electrode, 52, 53
... Operating circuit, 56 ... Pretreatment tube, 64 ... Acousto-optic element, 7
2 ... Movable mirror, 74 ... Image intensifier (II).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tamiki Takemori 1 126-1, Nomachi, Hamamatsu City, Shizuoka Prefecture Hamamatsu Photonics Co., Ltd.

Claims (10)

[Claims] 1. A spatial light modulator for inputting object images to be correlated at an appropriate time interval, subtracting each object image to record a subtracted image, and a spatial light modulator recorded on the spatial light modulator. A laser light source that generates laser light for reading the subtraction image, and a photodetector that receives an image of the light read from the spatial light modulator and outputs an electrical signal corresponding to the intensity of the received light. And an correlation display for displaying the magnitude of the correlation of each object image to be correlated based on the electric signal output from the photodetector. 2. The optical correlator according to claim 1, wherein a filter for performing low-pass filtering is arranged in the optical path of the subtracted image. 3. The optical correlation according to claim 1, wherein the spatial light modulator is divided into at least two split optical writing units whose optical writing units are independently operated. apparatus. 4. The optical correlation device according to claim 1, 2 or 3, wherein the spatial light modulator has a memory function. 5. The optical correlation device according to claim 1, wherein the spatial light modulator is a ferroelectric liquid crystal spatial light modulator. 6. A spatial light modulator for inputting object images to be correlated at an appropriate time interval and converting each object image into coherent information, and coherent information output from this spatial light modulator. A laser light source for generating a laser beam for reading out, a lens for Fourier-transforming the read-out image, and a pattern for subtracting and recording each Fourier-transformed pattern of coherent information based on each of the object images.
Of the spatial light modulator, a laser light source for generating a laser beam for reading the subtraction pattern recorded in the second spatial light modulator, a light beam for reading the received light beam, and a corresponding intensity of the received light beam. An optical detector comprising a photodetector that outputs an electric signal, and a correlation indicator that displays the magnitude of the correlation of each object image to be correlated based on the electric signal output from the photodetector. Correlator. 7. The optical correlation device according to claim 6, wherein a filter for performing low-pass filtering is arranged in the optical path of the subtraction pattern. 8. The second spatial light modulator according to claim 6, wherein the Fourier transform optical writing section is divided into at least two division writing sections that are independently operated. Optical correlation device. 9. The method according to claim 6, 7 or 8,
The spatial light modulator of is an optical correlator having a memory function. 10. The method according to claim 6, wherein
The optical correlation device, wherein the second spatial light modulator is a ferroelectric liquid crystal spatial light modulator.