JP2853430B2 - Optical information processing apparatus and aspherical Fourier transform lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information processing apparatus for optically performing image processing or image recognition in a visual recognition apparatus such as a robot, and a lens used in the apparatus.

[0002]

2. Description of the Related Art In recent years, image processing or image recognition technology has been required to process a larger number of pixels at a higher speed. Therefore, the development of an optical information processing apparatus that meets the above-mentioned requirements by utilizing the high-speed parallel computing function of light has been actively developed.

An optical information processing apparatus described in Japanese Patent Application No. 63-287016 will be described below as an example of a conventional optical information processing apparatus with reference to the drawings.

FIG. 8 shows a configuration of a conventional optical information processing apparatus. In FIG. 8, reference numeral 20 denotes a TV camera;
Represents a first image displaying an image captured by the TV camera 20.
A liquid crystal display 22; a semiconductor laser 22; a collimator lens 23 for collimating the light from the semiconductor laser 22; a first lens 24; and the first liquid crystal display 21 24 are located on the front focal plane of the camera. Reference numeral 25 denotes a second liquid crystal display, which is disposed on the rear focal plane of the first lens 24.

Reference numeral 26 denotes Fourier transform computer hologram data calculated in advance for each of a plurality of standard patterns using each picture element on the second liquid crystal display as a sampling point;
That is, a read-only memory (hereinafter referred to as ROM) in which data of an applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 25 is written, and 27 is a second lens, and a front focal point thereof. A second liquid crystal display 25 is arranged on the surface. Reference numeral 28 denotes a photodetector arranged on the rear focal plane of the second lens 27.

The operation of the conventional optical information processing apparatus configured as described above will be described below. First, when the target object is imaged by the TV camera 20, the image is displayed on the first liquid crystal display 21. The first liquid crystal display 21 is irradiated with coherent light from the semiconductor laser 22 which has been made parallel by the collimator lens 23. Since the first liquid crystal display 21 is disposed on the front focal plane of the first lens 24, the first lens of the target object is displayed on the rear focal plane of the first lens 24, that is, on the second liquid crystal display 25. 24 forms an optically converted Fourier transform image.

At this time, the second liquid crystal display 25 has a Fourier transform image of a specific standard pattern as an optical filter, and the data written in the ROM 26 becomes an input signal and becomes the second liquid crystal display. By spatially modulating the transmittance for each of the 25 picture elements, it is displayed in the form of a Fourier transform computer generated hologram.

Accordingly, a Fourier-transformed image obtained by optically converting the input image of the target object displayed on the first liquid crystal display 21 by the first lens 24 and a specific standard pattern
A Fourier transform image calculated in advance is superimposed on the second liquid crystal display 25.

Further, since the second liquid crystal display 25 is disposed on the front focal plane of the second lens 27,
When the target object and the two Fourier transform images of the specific standard pattern coincide with each other, that is, when the two are the same object, a bright spot is generated on the rear focal plane of the second lens 27, and the photodetector It is detected at 28. In this manner, optical image processing in which the optical filter based on the computer generated hologram displayed on the second liquid crystal display 25 acts as a matched filter is executed.

[0010]

However, the above-described configuration has a problem that the optical path length becomes longer and the device becomes larger due to the following reasons. That is, the wavelength of the semiconductor laser 22 is λ, the first liquid crystal display 21
Is the pixel pitch of P and the diameter of the Fourier transform image displayed on the second liquid crystal display 25 is D, the focal length f of the first lens 24 is f = D × P / λ. Given. Therefore, for example, P = 50 μm and λ = 0.8 μm
If m and D = 60 mm, a lens with f = 3125 mm is required. For this reason, as shown in FIG. 8, the distance between the first liquid crystal display 21 and the second liquid crystal display 25 has a problem that it is extremely long at 2 × f = 6250 mm.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides an optical information processing apparatus in which the distance between the first liquid crystal display and the second liquid crystal display is shortened, and an aspherical part of a constituent lens thereof. It is an object of the present invention to provide a Fourier transform lens in which the distance between the first liquid crystal display and the second liquid crystal display is reduced and the imaging characteristics are improved.

[0012]

According to a first aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; A convex lens, a second spatial light modulator arranged near the rear focal plane of the first lens, and a second lens arranged near the second spatial light modulator. An optical information processing apparatus characterized in that:

According to a second aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; a first convex lens disposed in the vicinity thereof; , A second spatial light modulating element disposed near the rear combined focal plane of the first convex lens and the concave lens, and a second spatial light modulating element disposed near the second spatial light modulating element. An optical information processing apparatus comprising: a second convex lens.

The optical information processing apparatus according to claim 3 is
A first spatial light modulator for displaying an input image, a first convex lens disposed in the vicinity thereof, a concave lens disposed behind the first convex lens, and a rear side of the first convex lens and the concave lens A second spatial light modulator arranged near the combined focal plane, and a second convex lens arranged near the second spatial light modulator;
An optical information processing apparatus, characterized in that one surface of a convex lens of (1) is a flat surface, and is disposed in close contact with the first and second spatial light modulators, respectively.

An aspherical surface filter according to a fourth aspect of the present invention.
The Rie transform lens is a first convex lens in order from the object plane side,
A concave lens, a second convex lens, and the second lens
Characterized in that at least one surface of the convex lens has an aspherical surface.

[0016]

According to the first aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; a convex lens disposed in the vicinity thereof; and a rear focal plane of the first lens. Providing the second spatial light modulation element disposed in the vicinity and the second lens disposed in the vicinity of the second spatial light modulation element allows the first spatial light modulation element and the second spatial light modulation element to be provided. An object of the present invention is to reduce the distance of the spatial light modulator and reduce the size of the optical information processing device.

According to a second aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; a first convex lens disposed near the first spatial light modulator; , A second spatial light modulating element disposed near the rear combined focal plane of the first convex lens and the concave lens, and a second spatial light modulating element disposed near the second spatial light modulating element. The distance between the first spatial light modulator and the second spatial light modulator is further reduced by providing the second convex lens as compared with the optical information processing apparatus according to claim 1, and the optical information processing apparatus is reduced in size. Is made possible.

Further, the optical information processing apparatus according to claim 3 is
A first spatial light modulator for displaying an input image, a first convex lens disposed in the vicinity thereof, a concave lens disposed behind the first convex lens, and a rear side of the first convex lens and the concave lens A second spatial light modulator arranged near the combined focal plane, and a second convex lens arranged near the second spatial light modulator;
Is characterized in that one surface of the convex lens has a flat surface, and is arranged in close contact with the first and second spatial light modulators, thereby shortening the distance between the first spatial light modulator and the second spatial light modulator. In addition, multiple reflection in the spatial light modulator is prevented.

The aspherical surface filter according to claim 4 of the present invention.
The Rie transform lens is a first convex lens in order from the object plane side,
A concave lens, a second convex lens, and the second lens
The at least one surface of the convex lens has an aspherical surface, so that the distance between the first spatial light modulator and the second spatial light modulator can be shortened, the optical information processing apparatus can be downsized, and the principal ray This is an aspherical Fourier transform lens in which the aberration correction for the imaging of the pupil and the imaging of the object is made independent, and the imaging characteristics are improved.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical information processing apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the optical information processing apparatus according to claim 1 of the present invention. In FIG. 1, 1 is a TV camera, 5 is a T
A first liquid crystal display for displaying an image picked up by the V camera 1; 2 a semiconductor laser; 3 a semiconductor laser 2
A collimator lens 4 for collimating the light from the first lens 4 is a first lens, and a first liquid crystal display 5 is arranged near the first lens 4. Reference numeral 7 denotes a second liquid crystal display, which is arranged near the rear focal plane of the first lens 4.

Reference numeral 10 denotes data of a Fourier transform computer generated hologram which is calculated in advance for each of a plurality of reference patterns using each picture element on the second liquid crystal display as a sampling point;
That is, a memory in which data of an applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 7 is written. Reference numeral 6 denotes a second lens, and the second lens 6 and the first lens 4 The second liquid crystal display 7 is arranged at the combined focal position of the above. Reference numeral 8 denotes a third lens, on which a second liquid crystal display 7 is disposed on the front focal plane. Reference numeral 9 denotes a photodetector, which is arranged behind the third lens 8.

The operation of the optical information processing apparatus of the present embodiment configured as described above will be described below. First, T
When the target object is imaged by the V camera 1, the image is displayed on the first liquid crystal display 5. The first liquid crystal display 5 is illuminated by coherent light from the semiconductor laser 2 which has been collimated by the collimator lens 3, and the input image displayed on the first liquid crystal display 5 is the first image. Irradiated by convergent light by one lens 4.

The Fourier transform using the convergent light is performed in a conventional 2f system, that is, in a system in which the distance between the first spatial light modulator and the second spatial light modulator is 2f. -Exp [i (k / 2d) (X
f ² + Yf ² )]. Here, k is the wave number, d is the distance between the first liquid crystal display 5 and the rear focal plane of the first lens 4, and Xf and Yf are the coordinates on the focal plane. This added phase term exp [i (k /
2d) (Xf ² + Yf ² )] is caused by Fresnel diffraction at a distance d between the first liquid crystal display 5 and the rear focal plane of the first lens 4.

On the other hand, if the function of the lens is regarded as wave optics, it can be considered as a phase conversion function. This phase conversion function can be written as exp [−i (k / 2f) (Xf ² + Yf ² )], where f is the focal length. Therefore, if the focal length f ₂ of the _second lens 6 is made equal to the distance d between the first liquid crystal display 5 and the rear focal plane of the first lens 4, an extra part due to Fresnel diffraction at the distance d is obtained. The phase term exp [i (k / 2d) (Xf ²
+ Yf ² )] and the phase conversion function exp of the second lens 6
[−i (k / 2f) (Xf ² + Yf ² )] cancels out, and a complete Fourier transform can be realized. Since d = f, the diffracted light on the first liquid crystal display 5 can be collimated.

Therefore, the first lens 4 and the second lens 6
An optically converted Fourier-transformed image of the target object is formed on the composite focal plane, i.e., the second liquid crystal display 7.

At this time, the second liquid crystal display 7
The Fourier transform image of a specific reference pattern is used as an optical filter, and the data written in the memory 10 becomes an input signal to spatially modulate the transmittance for each picture element of the second liquid crystal display 7. By doing so, it is displayed in the form of a Fourier transform computer generated hologram.

Therefore, a Fourier transform image obtained by optically transforming the input image of the target object displayed on the first liquid crystal display 5 by the first lens 4 and the second lens 6 and a specific reference pattern The Fourier-transformed image calculated in advance for the image is superimposed on the second liquid crystal display 7. Further, since the second liquid crystal display 7 is disposed on the front focal plane of the third lens 8, when the target object and the two Fourier transform images of the specific reference pattern coincide with each other, that is, when the two are coincident with each other. Are the same object, a bright spot is generated on the rear focal plane of the third lens 8 and detected by the photodetector 9. In this way,
Optical information processing is performed in which an optical filter based on a computer generated hologram displayed on the second liquid crystal display 7 acts as a matched filter.

As described above, according to the present embodiment, the distance d is approximately equal to the focal length f of the first lens, and the focal length of the second lens 6 is equal to the distance d. The distance 1 between the display 5 and the second liquid crystal display 7 can be substantially equal to the focal length f of the first lens 4. That is, the distance L is reduced to about 1/2 compared with the conventional example.
Thus, the optical information processing apparatus can be significantly reduced in size.

Next, an optical information processing apparatus according to a second embodiment of the present invention will be described with reference to the drawings showing the configuration of the embodiment. FIG. 2 is a side view of a first embodiment of the optical information processing apparatus according to claim 2 of the present invention. In FIG. 2, reference numeral 11 denotes a TV camera, 15 denotes a first liquid crystal display for displaying an image captured by the TV camera 11,
12 is a semiconductor laser, 13 is a collimator lens for collimating light from the semiconductor laser 2, 14 is a first convex lens, and a first liquid crystal display 15 is a rear side of the first convex lens 14. It is located near. Reference numeral 16 denotes a concave lens, and reference numeral 18 denotes a second liquid crystal display, which is arranged near a combined focal plane of the first convex lens 14 and the concave lens 16.

Reference numeral 21 denotes data of a Fourier transform computer generated hologram calculated in advance for each of a plurality of reference patterns using each picture element on the second liquid crystal display 18 as a sampling point.
A memory in which data of an applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 18 is written. Reference numeral 17 denotes a second convex lens, and the second convex lens 17 and the first convex lens A second liquid crystal display 18 is arranged at a combined focal position of the convex lens 14 and the concave lens 16.
Reference numeral 19 denotes a fourth lens, and a second liquid crystal display 18 is disposed on a front focal plane of the fourth lens. Reference numeral 20 denotes a photodetector, which is arranged behind the fourth lens 19.

Hereinafter, the first convex lens 14 and the concave lens 1
6, and the relational expression that the focal length and the lens interval of the second convex lens 17 should satisfy will be described with reference to FIG.

In FIG. 3, a is the distance between the first convex lens 14 and the concave lens 16, b is the distance between the concave lens 16 and the second convex lens 17, and S 1 is the distance between the first convex lens 14 and the first liquid crystal display 15. The interval, S2, is the second convex lens 1
7, the distance between the second liquid crystal display 18 and fs is the first
, K is the telephoto ratio of the telephoto system, and m is the rear group of the telephoto system, that is, the concave lens 16.
The magnification of each is shown. F1, f2, and f3 are the first convex lens 14, the concave lens 16, and the second
Denotes a focal length of the convex lens 17, and h1 denotes a height of a light ray incident on the first convex lens 14.

Further, the solid line in FIG. 3 is the image of the pupil, that is, the principal ray of the system, and shows the optical Fourier transform function of the input image displayed on the first liquid crystal display 15. . On the other hand, the dashed line shows the image of the object,
This is a function of collecting the diffracted light on the first liquid crystal display 15 and converting it into parallel light.

Here, the second liquid crystal display 18 is
The first convex lens 14 and the concave lens 16 are arranged near the combined focal position. Therefore, k · fs is substantially equal to the total combined focal length of the first convex lens 14, the concave lens 16, and the second convex lens 17.

In the optical system configured as described above, in order to satisfy both the pupil image formation and the object image formation, the first convex lens 14 is formed by the phase conversion action of the second convex lens 17.
It is necessary to correct the phase term generated by the concave lens 16 and the concave lens 16, and satisfy the function of the diffractive light from the first liquid crystal display 15 being parallelized by the concave lens 16 and the second convex lens 17. Conditions satisfying both functions are expressed by the following relational expressions.

1 / f1 + (f1-a) / (f1 · f2) + (k · fs-ab) (f1-a) / (f3 · (k · fs-a) · f1) = 1 / (fs · h1) ... (Formula 1) fs = (k ・ fs-a) S2 ・ f1 / ((f1-a) (k ・ fs-ab))… (Formula 2) f2 = (f1-a) (k ・ fs -a) / (f1-k · fs) (Equation 3) f3 = b + f2 (a-S1) / (a-S1 + f2) (Equation 4) The first convex lens 14, the concave lens 16, and the The two convex lenses 17, the first liquid crystal display 15, and the second liquid crystal display 18 are configured and arranged to satisfy the above four equations.

The operation of the optical information processing apparatus of the present embodiment configured as described above will be described below. First, T
When the target object is imaged by the V camera 11, the image is displayed on the first liquid crystal display 15. The first liquid crystal display 15 is irradiated with coherent light from the semiconductor laser 12 which has been made parallel by the collimator lens 13. This first liquid crystal display 15
Are the first convex lens 14 and the concave lens 1
An optically converted Fourier transformed image of the target object is formed on the second liquid crystal display 18 after being completely Fourier transformed by the sixth and second convex lenses 17.

At this time, on the second liquid crystal display 18, a Fourier transform image of a specific reference pattern as an optical filter and data written in the memory 21 as an input signal become the second liquid crystal display. By spatially modulating the transmittance for each picture element on the display 18, the picture is displayed in the form of a Fourier transform computer generated hologram.

Accordingly, the input image of the target object displayed on the first liquid crystal display 15 is optically converted by the first convex lens 14, the concave lens 16 and the second convex lens 17 into a Fourier-transformed image. The Fourier-transformed image calculated in advance for the reference pattern of FIG.
8 are superimposed.

Since the second liquid crystal display 18 is arranged on the front focal plane of the fourth lens 19,
When the two Fourier transform images of the target object and the specific reference pattern coincide with each other, that is, when the two are the same object, a bright spot is generated on the rear focal plane of the fourth lens 19 and the photodetector Detected at 20.

In this manner, optical information processing in which the optical filter based on the computer generated hologram displayed on the second liquid crystal display 18 acts as a matched filter is executed.

As described above, according to this embodiment, since the first convex lens 14 and the concave lens 16 constitute a telephoto system having a telephoto ratio k, for example, if k = 0.3, the first liquid crystal display 15 The interval between the second liquid crystal displays 18 is approximately 0.3f, which can be reduced to about 1/6 as compared with the conventional example, and the optical information processing apparatus can be significantly reduced in size.

Next, a second embodiment of the optical information processing apparatus according to the second aspect of the present invention will be described with reference to FIG. FIG.
Is a second optical information processing apparatus according to claim 2 of the present invention.
It is a lineblock diagram of an Example of a. In FIG. 4, 31 is a TV camera, 35 is a first liquid crystal display for displaying an image taken by the TV camera 31, 32 is a semiconductor laser,
33 is a collimator lens for collimating the light from the semiconductor laser 32, 34 is a first convex lens, and the first liquid crystal display 35 is arranged near the front side of the first convex lens 34. Reference numeral 36 denotes a concave lens, and reference numeral 38 denotes a second liquid crystal display, which is arranged near the combined focal plane of the first convex lens 34 and the concave lens 36.

Reference numeral 41 denotes a data of a Fourier transform computer generated hologram calculated in advance for each of a plurality of reference patterns using each picture element on the second liquid crystal display 38 as a sampling point.
A memory 37 in which data of an applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 38 is written. Reference numeral 37 denotes a second convex lens, and the second convex lens 37 and the first A second liquid crystal display 38 is arranged at a combined focal position of the convex lens 34 and the concave lens 36.
Reference numeral 39 denotes a fourth lens, on the front focal plane of which a second liquid crystal display 38 is arranged. Reference numeral 40 denotes a photodetector, which is disposed behind the fourth lens 39.

Hereinafter, the first convex lens 34 and the concave lens 3
6, and the relational expression that the focal length and the lens interval should satisfy for the second convex lens 37 will be described with reference to FIG.

In FIG. 5, a is the distance between the first convex lens 34 and the concave lens 36, and b is the concave lens 36 and the second convex lens 37.
, S1 is the distance between the first convex lens 34 and the first liquid crystal display 35, S2 is the distance between the second convex lens 37 and the second liquid crystal display 38, fs is the first convex lens 34 and the concave lens 36. , K is the telephoto ratio of the telephoto system, m
Denotes the rear group of the telephoto system, that is, the magnification of the concave lens 36. F1, f2, and f3 are respectively
The focal lengths of the first convex lens 34, the concave lens 36, and the second convex lens 37 are shown, and h1 is the first convex lens 34.
3 shows the height of the incident light beam to the light source.

Further, the solid line in FIG. 5 is the image of the pupil, that is, the principal ray of the system, and shows the optical Fourier transform function of the input image displayed on the first liquid crystal display 35. . On the other hand, the dashed line shows the image of the object,
This is a function of collecting the diffracted light on the first liquid crystal display 35 and converting it into parallel light. Here, the second liquid crystal display 38 is provided with the first convex lens 3.
4 and the concave lens 36 are disposed in the vicinity of the combined focal position. Therefore, k · fs is substantially equal to the total combined focal length of the first convex lens 34, the concave lens 36, and the second convex lens 37.

In the optical system configured as described above, in order to satisfy both the image formation of the pupil and the image formation of the object, the first convex lens 34 and the concave lens 36 use the phase conversion function of the second convex lens 37. While correcting the generated phase term,
It is necessary that the concave lens 36 and the second convex lens 37 satisfy the function of converting the diffracted light from the first liquid crystal display 35 into parallel light. Conditions satisfying both functions are expressed by the following relational expressions.

1 / f1 + (f1-a) / (f1 · f2) + (k · fs-ab) (f1-a) / (f3 · (k · fs-a) · f1) = 1 / (fs · h1)… (Equation 5) fs = (k ・ fs-a) S2 ・ f1 / ((f1-a) (k ・ fs-ab))… (Equation 6) f2 = (f1-a) (k ・ fs -a) / (f1-k ・ fs)… (Formula 7) f3 = b + f2 (f1 ・ S1-a ・ f1-a ・ S1) / (f1 ・ S1-a ・ f1-a ・ S1-f1 ・f2-f2 · S1) (Equation 8) The first convex lens 34, the concave lens 36, the second convex lens 37, the first liquid crystal display 35, and the second liquid crystal display 38 are obtained from the above (Equation 5) according to (8). Expression 4) is configured and arranged to satisfy the four expressions.

The operation of the optical information processing apparatus of the present embodiment configured as described above will be described below. First, T
When the target object is imaged by the V camera 31, the image is displayed on the first liquid crystal display 35. The first liquid crystal display 35 is illuminated by coherent light from the semiconductor laser 32, which is collimated by the collimator lens 33. This first liquid crystal display 35
Are the first convex lens 34 and the concave lens 3
6 and the second convex lens 37, a complete Fourier transform is performed, and an optically transformed Fourier transform image of the target object is formed on the second liquid crystal display 38.

At this time, on the second liquid crystal display 38, a Fourier transform image of a specific reference pattern as an optical filter and data written in the memory 41 as an input signal become the second liquid crystal display. By spatially modulating the transmittance for each picture element on the display 38, it is displayed in the form of a Fourier transform computer generated hologram.

Accordingly, a Fourier-transformed image obtained by optically converting the input image of the target object displayed on the first liquid crystal display 35 by the first convex lens 34, the concave lens 36, and the second convex lens 37 is specified. The Fourier transform image calculated in advance for the reference pattern of
8 are superimposed.

Further, since the second liquid crystal display 38 is disposed on the front focal plane of the fourth lens 39,
When the two Fourier transform images of the target object and the specific reference pattern coincide with each other, that is, when the two are the same object, a luminescent spot is generated on the rear focal plane of the fourth lens 39 and the photodetector It is detected at 40. In this way, optical information processing in which the optical filter based on the computer generated hologram displayed on the second liquid crystal display 38 acts as a matched filter is executed.

As described above, according to this embodiment, since the first convex lens 34 and the concave lens 36 constitute a telephoto system having a telephoto ratio k, for example, when k = 0.3, the first liquid crystal display 35 The interval between the second liquid crystal displays 38 is approximately 0.3f, which can be reduced to about 1/6 as compared with the conventional example, so that the optical information processing apparatus can be significantly reduced in size.

Next, an optical information processing apparatus according to a third aspect of the present invention will be described with reference to the drawings. FIG. 6 is a block diagram of one embodiment of the optical information processing apparatus according to claim 3 of the present invention. In FIG. 6, reference numeral 51 denotes a TV camera;
Reference numeral 5 denotes a first liquid crystal display for displaying an image taken by the TV camera 51; 52, a semiconductor laser; 53, a collimator lens for collimating light from the semiconductor laser 52; The first liquid crystal display 55 is a convex lens and is disposed near the front side of the first convex lens 54.

The first surface of the first convex lens 54 is formed of a flat surface, and is arranged in close contact with the first liquid crystal display 55. Reference numeral 56 denotes a concave lens, and reference numeral 58 denotes a second liquid crystal display, which is arranged near the combined focal plane of the first convex lens 54 and the concave lens 56. Reference numeral 51 denotes a second liquid crystal display 5 for a plurality of reference patterns.
The data of the Fourier transform computer generated hologram calculated in advance by using each picture element on the sampling point 8 as a sampling point, that is, the data of the applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 58 is obtained. The written memory 57 is a second convex lens, and a second liquid crystal display 58 is disposed at a combined focal position of the second convex lens 57, the first convex lens 54, and the concave lens 56.

The second surface of the second convex lens 57 is formed as a flat surface, and is arranged in close contact with the second liquid crystal display 58. Reference numeral 59 denotes a fourth lens, on which a second liquid crystal display 58 is disposed on the front focal plane. Reference numeral 60 denotes a photodetector, which is disposed behind the fourth lens 59.

Hereinafter, the first convex lens 54 and the concave lens 5
Regarding the sixth and second convex lenses 57, the relational expressions to be satisfied by their focal lengths and lens intervals are the same as in the second embodiment of the second aspect of the present invention (Equation 5).
To (Equation 8).

The first convex lens 54, the concave lens 56, the second convex lens 57, the first liquid crystal display 55, and the second liquid crystal display 58 are configured and arranged to satisfy the above four equations.

The operation of the optical information processing apparatus of the present embodiment configured as described above will be described below. First, T
When the target object is imaged by the V camera 51, the image is displayed on the first liquid crystal display 55. The first liquid crystal display 55 is illuminated with coherent light from the semiconductor laser 52 which has been collimated by the collimator lens 53. This first liquid crystal display 55
Are input to the first convex lens 54 and the concave lens 5
6 and the second convex lens 57 completely form a Fourier transform, and an optically transformed Fourier transform image of the target object is formed on the second liquid crystal display 58.

At this time, on the second liquid crystal display 58, a Fourier transform image of a specific reference pattern as an optical filter and data written in the memory 61 as an input signal become the second liquid crystal display. By spatially modulating the transmittance for each picture element on the display 58, it is displayed in the form of a Fourier transform computer generated hologram.

Accordingly, a Fourier-transformed image obtained by optically converting the input image of the target object displayed on the first liquid crystal display 55 by the first convex lens 54, the concave lens 56, and the second convex lens 57 is specified. The Fourier transform image calculated in advance for the reference pattern of
8 are superimposed.

Since the second liquid crystal display 58 is disposed on the front focal plane of the fourth lens 59,
When the target object and the two Fourier transform images of the specific reference pattern match, that is, when the two are the same object, a bright spot is generated on the rear focal plane of the fourth lens 59, and the photodetector Detected at 60. In this way, optical information processing in which the optical filter based on the computer generated hologram displayed on the second liquid crystal display 58 acts as a matched filter is executed.

As described above, according to this embodiment, since the first convex lens 54 and the concave lens 56 constitute a telephoto system having a telephoto ratio k, for example, when k is set to 0.3, the first liquid crystal display 55 The interval between the second liquid crystal displays 58 is approximately 0.3f, which can be reduced to about 1/6 as compared with the conventional example, so that the optical information processing apparatus can be significantly reduced in size.

Further, in this embodiment, the first convex lens 5
The fourth and second convex lenses 57 are arranged in close contact with the first liquid crystal display 55 and the second liquid crystal display 58, respectively. As a result, it is possible to prevent the surfaces of the first liquid crystal display 55 and the second liquid crystal display 58 from directly contacting the air.

Thus, the first liquid crystal display 55
Since the reflectance of light on the surface of the second liquid crystal display 58 can be reduced, the distance between the surfaces of the first liquid crystal display 55 and the first convex lens 54, and between the surface of the second liquid crystal display 58 and the second convex lens Multiple reflection between the 57 surfaces can be prevented.

As a result, it is possible to prevent the occurrence of unwanted light and dark fringes due to the localization of interference fringes caused by multiple reflection on the surfaces of the first liquid crystal display 55 and the second liquid crystal display 58. That is, since the input image or the transmittance distribution of the optical filter is not disturbed by such undesired light and dark fringes, the recognition accuracy of the optical information processing apparatus can be improved.

The structure of the first liquid crystal display 55 and the second liquid crystal display 58 is a multilayer structure having different refractive indexes. Therefore, multiple reflections may occur inside the liquid crystal display. Against this internal multiple reflection, an anti-reflection effect can be obtained by appropriately setting the refractive index of the first convex lens 54 and the second convex lens 57 or the refractive index of the optical thin film formed on the surface by vapor deposition or the like. Can be. Thus, it is possible to prevent interference fringes caused by multiple reflections from being localized and to generate undesired light and dark, so that the recognition accuracy of the optical information processing apparatus can be improved.

In this embodiment, the contact method generally called optical contact is used. However, the first convex lens 54 and the first liquid crystal display 55 and the second convex lens 57 and the second liquid crystal display 58 are connected. For example, a structure may be adopted in which the medium is brought into close contact with a medium such as silicon oil.

Next, an embodiment of the aspherical Fourier transform lens according to claim 4 of the present invention will be described with reference to FIG. FIG. 7 is a side view of one embodiment of the aspherical Fourier transform lens according to claim 4 of the present invention. 7, reference numeral 71 denotes a TV camera; 75, a first liquid crystal display for displaying an image captured by the TV camera 71;
Is a semiconductor laser, 73 is a collimator lens for collimating the light from the semiconductor laser 72, 74 is a first convex lens, and the first liquid crystal display 75 is near the front side of the first convex lens 74. Are located. Reference numeral 76 denotes a concave lens, and reference numeral 78 denotes a second liquid crystal display, which is arranged near the combined focal plane of the first convex lens 74 and the concave lens 76.

Reference numeral 81 denotes data of a Fourier transform computer generated hologram calculated in advance for each of a plurality of reference patterns using each picture element on the second liquid crystal display 78 as a sampling point.
A memory in which data of an applied voltage corresponding to the transmittance of each picture element of the second liquid crystal display 78 is written. Reference numeral 77 denotes a second convex lens, the first surface of which is an aspheric surface. A second liquid crystal display 78 is arranged at a combined focal position of the second convex lens 77, the first convex lens 74, and the concave lens. Reference numeral 79 denotes a fourth lens, and a second liquid crystal display 78 is disposed on the front focal plane. Reference numeral 80 denotes a photodetector, which is arranged behind the fourth lens 79.

In the optical system configured as described above, in order to satisfy both the image formation of the pupil and the image formation of the object, the first convex lens 74 and the concave lens 76 use the phase conversion action of the second convex lens 77. It is necessary to correct the unnecessary phase term to be generated and to satisfy the function of making the diffracted light from the first liquid crystal display 75 parallel by the concave lens 76 and the second convex lens 77. The conditions for satisfying both functions are expressed by the above-mentioned relational expressions (5) to (8), as in the second embodiment of the present invention and the first embodiment of the present invention. Is done.

The first convex lens 74, the concave lens 76, the second convex lens 77, the first liquid crystal display 75, and the second liquid crystal display 78 satisfy the above relational expressions (5) to (8). It is arranged as follows.

These four equations are equations for determining the power arrangement obtained by thin paraxial ray tracing, and the specific surface curvature, glass material, and thickness of each lens are calculated based on the actual light ray based on this power arrangement. This can only be determined by optimizing the aberrations obtained by performing the tracking.

Now, the second convex lens 5 in the present embodiment will be described.
Numeral 7 is responsible for the imaging of the pupil and the imaging of the object, that is, two different imagings, the principal ray of the system and the main ray of the system.
Accordingly, the second convex lens 57 is used for image formation of an object.
It is necessary to optimize five aberrations, which are so-called Seidel aberrations: spherical aberration, coma, astigmatism, distortion, and field curvature, and optimize pupil aberration for pupil imaging. These two different aberration corrections correspond to the principal ray and the marginal ray, respectively. Therefore, by using an aspheric lens like the second convex lens 57 in the present embodiment, it is possible to set the optimum surface curvature for each of the principal ray and the marginal ray.

The operation of the embodiment constructed as described above will be described below. First, when the target object is imaged by the TV camera 71, the image is displayed on the first liquid crystal display 75. The first liquid crystal display 75 is irradiated with coherent light from the semiconductor laser 72 which has been made parallel by the collimator lens 73. The input image displayed on the first liquid crystal display 75 is completely Fourier-transformed by the first convex lens 74, the concave lens 76, and the second convex lens 77, and the optical image of the target object is displayed on the second liquid crystal display 78. To form a Fourier-transformed image.

At this time, on the second liquid crystal display 78, a Fourier transform image of a specific reference pattern as an optical filter and data written in the memory 81 as an input signal become the second liquid crystal display. By spatially modulating the transmittance for each picture element on the display 78, it is displayed in the form of a Fourier transform computer generated hologram.

Therefore, the input image of the target object displayed on the first liquid crystal display 75 is optically converted by the first convex lens 74, the concave lens 76, and the second convex lens 77 into a Fourier-transformed image, The Fourier transform image calculated in advance for the reference pattern of
8 are superimposed.

Since the second liquid crystal display 78 is disposed on the front focal plane of the fourth lens 79,
When the two Fourier transform images of the target object and the specific reference pattern coincide with each other, that is, when the two are the same object, a bright spot is generated on the rear focal plane of the fourth lens 79, and the light detector Detected at 80. In this manner, optical information processing in which the optical filter based on the computer generated hologram displayed on the second liquid crystal display 78 acts as a matched filter is executed.

As described above, according to this embodiment, since the first convex lens 74 and the concave lens 76 constitute a telephoto system having a telephoto ratio k, for example, when k = 0.3, the first liquid crystal display 75 is The interval between the second liquid crystal displays 78 is approximately 0.3f, which can be reduced to about 1/6 as compared with the conventional example, so that the optical information processing apparatus can be significantly reduced in size.

Further, by making the second convex lens 77 an aspherical lens, it is possible to optimize aberration correction for the image formation of the object and the image of the pupil, and to provide a Fourier transform lens having good image formation characteristics. Can be provided.

In the above five embodiments, each lens is a single lens. However, these lenses may be constituted by a doublet or other plural lenses. Further, in each of the above five embodiments, each spatial light modulation element is constituted by a transmission type liquid crystal display, but other spatial light modulation elements such as a reflection type liquid crystal display may be used.

[0083]

As described above, the optical information processing apparatus according to the first aspect of the present invention comprises a first spatial light modulation element for displaying an input image, a convex lens disposed in the vicinity of the first spatial light modulation element, The provision of the second spatial light modulator disposed near the rear focal plane of the lens and the second lens disposed near the second spatial light modulator allows the first spatial light to be provided. The distance between the modulation element and the second spatial light modulation element can be reduced, and the optical information processing device can be downsized.

According to a second aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; a first convex lens disposed near the first spatial light modulator; , A second spatial light modulator disposed near the rear composite focal plane of the first convex lens and the concave lens, and a second spatial light modulator disposed near the second spatial light modulator. The distance between the first spatial light modulator and the second spatial light modulator is further reduced by providing the second convex lens as compared with the optical information processing device according to claim 1, and the size of the optical information processing device is reduced. Can be made possible.

According to a third aspect of the present invention, there is provided an optical information processing apparatus, comprising: a first spatial light modulator for displaying an input image; a first convex lens disposed in the vicinity thereof; , A second spatial light modulating element disposed near the rear combined focal plane of the first convex lens and the concave lens, and a second spatial light modulating element disposed near the second spatial light modulating element. A second convex lens, and one surface of each of the first and second convex lenses is a flat surface, and each of the first and second convex lenses is disposed in close contact with the first and second spatial light modulation elements. The distance between the spatial light modulator and the second spatial light modulator can be reduced, and the optical information processing device can be downsized. Further, multiple reflection in the spatial light modulator can be prevented, and the characteristics of the optical information processing device can be improved.

The aspherical surface filter according to claim 4 of the present invention.
The Rie transform lens is a first convex lens in order from the object plane side,
A concave lens, a second convex lens, and the second lens
The at least one surface of the convex lens has an aspherical surface, so that the distance between the first spatial light modulator and the second spatial light modulator can be shortened, the optical information processing apparatus can be downsized, and the principal ray In addition, aberration correction for the imaging of the pupil and the imaging of the object can be made independent, and the imaging characteristics can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of an optical information processing apparatus according to claim 1 of the present invention;

FIG. 2 shows a first example of the optical information processing apparatus according to claim 2 of the present invention.
Configuration diagram of the embodiment device

FIG. 3 is an explanatory diagram of a lens optical system in the embodiment apparatus of FIG. 2;

FIG. 4 shows a second embodiment of the optical information processing apparatus according to claim 2 of the present invention.
Configuration diagram of the embodiment device

FIG. 5 is an explanatory view of a lens optical system in the embodiment device of FIG. 4;

FIG. 6 is a configuration diagram of an embodiment of an optical information processing apparatus according to claim 3 of the present invention.

FIG. 7 is a block diagram of an embodiment of an aspherical Fourier transform lens according to claim 4 of the present invention.

FIG. 8 is a configuration diagram of a conventional optical information processing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 TV camera 2 Semiconductor laser 3 Collimator lens 4 First lens 5 First liquid crystal display 6 Second lens 7 Second liquid crystal display 8 Third lens 9 Photodetector 10 Memory

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Claims (4)

(57) [Claims] 1. A first spatial light modulator for displaying an input image, a convex lens disposed near the first spatial light modulator, and a second spatial light modulator disposed near a rear focal plane of the first lens. And a second spatial light modulating element arranged near the second spatial light modulating element.
An optical information processing apparatus comprising: a lens; 2. A first spatial light modulating element for displaying an input image, a first convex lens disposed near the first spatial light modulating element,
A concave lens disposed behind the convex lens, a second spatial light modulating element disposed in the vicinity of the rear combined focal plane of the first convex lens and the concave lens, and disposed in the vicinity of the second spatial light modulating element An optical information processing apparatus, comprising: a second convex lens formed as described above. 3. A first spatial light modulator for displaying an input image, a first convex lens disposed in the vicinity of the first spatial light modulator,
A concave lens disposed behind the convex lens, a second spatial light modulating element disposed in the vicinity of the rear combined focal plane of the first convex lens and the concave lens, and disposed in the vicinity of the second spatial light modulating element An optical information processing apparatus comprising: a first convex lens, a first convex lens, and a second convex lens. apparatus. 4. An aspherical surface lens comprising: a first convex lens, a concave lens, and a second convex lens in order from the object surface side, wherein at least one surface of the second convex lens is formed by an aspheric surface. Rier transform lens.