JPH0652320A - Optical pattern recognizing device provided with coordinate transforming function - Google Patents

Abstract

PURPOSE:To exactly recognize a pattern at high speed even when the size or rotating angle of an object to be recognized is variously changed. CONSTITUTION:This device is composed of an optical coordinate transformation part to provide a coordinate transformed image converted to a desired coordinate system while using a coordinate transformation optical filter array 44 and a coordinate transformation lens array 47 by displaying one reference image containing a required target and one image to be correlated to be newly inputted on a first electric write type spatial light modulator 3 for input image at least, and a joint transformation correlator part to provide the coefficient of correlation between the coordinate transformed image of the reference image and the coordinate transformed image of the image to be correlated by displaying the coordinate transformation intensity distribution image of the coordinate transformed image provided at the optical coordinate transformation part on a first optical write type spatial light modulator 13 for coordinate transformation, performing Fourier transformation to that image, displaying the Fourier transformed intensity distribution image on an optical write type spatial light modulator 105 for Fourier transformation, and performing Fourier transformation to that image again. Thus, the reference image or the kind of coordinate transformation can be easily changed at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical coordinate conversion and optical correlation processing using coherent light on a two-dimensional image obtained from an image pickup device such as a CCD camera in the fields of optical information processing and optical measurement. The present invention relates to an apparatus for automatically performing pattern recognition and measurement by applying

[0002]

2. Description of the Related Art As a correlator for optically recognizing a pattern, two types, a VanderLugt type and a joint conversion type, are generally well known. Either way,
Since it is based on the optical Fourier transform using a lens, the parallel movement of the correlated object to be recognized can be recognized without any problem (shift invariance). On the other hand, it is known that it is not invariable with respect to the rotation or size change of the correlated object, and that the recognition ability decreases depending on the degree.

Therefore, conventionally, for example, like characters and parts,
When optically measuring and recognizing objects with different shapes, sizes, orientations, positions, etc., first, the correlated object is converted into a two-dimensional image (correlated image), and secondly the correlated image is converted. It is a general procedure to convert to a desired coordinate system that is invariant to changes required for recognition such as rotation and size change, and thirdly to measure and recognize the coordinate conversion image. is there.

The types of coordinate conversion include polar coordinate conversion when recognizing objects having different orientations and measuring rotation angles, and recognizing objects having different orientations and sizes and measuring rotation angles and magnifications. For example, coordinate conversion such as converting (x, y) coordinates to (1nr, θ) coordinates,
Various types of coordinate transformations are used depending on the purpose. Here, r and θ are polar coordinates.

First, an outline of the optical coordinate conversion method is shown in FIG. In this method, a liquid crystal television 303 displaying an image to be converted and a coordinate conversion optical filter 304 are arranged in an overlapping manner on the front focal plane of the coordinate conversion lens 307, and parallel coherent light is emitted from the back of the liquid crystal television 303. As a result, a desired coordinate conversion image can be obtained on the liquid crystal light valve 308 arranged on the back focal plane of the coordinate conversion lens 307. Here, the coordinate conversion optical filter 304
Is produced by a computer generated hologram. Further, it goes without saying that the liquid crystal television 303 and the coordinate conversion optical filter 304 may be placed before each other as long as they are arranged close to each other.

As a light modulating material for the liquid crystal light valve 308, a material using TN liquid crystal is often used. Further, instead of the liquid crystal light valve 308, B is used as a light modulation material.
An optical writing type spatial light modulator using a crystal such as SO crystal (Bi ₁₂ SiO ₂₀ ) may be used. After irradiating these spatial light modulators with coordinate-converted images for display and storage, the coherent light is radiated to read the coordinate-converted images for use in processing such as pattern recognition. In addition, instead of the optical writing type spatial light modulator, an image pickup device such as a CCD camera is used to receive light and the obtained image signal is input to an electrically writing type spatial light modulator such as a liquid crystal television. There is also.

Next, as a pattern recognition method using coordinate transformation, a method of applying a normal VanderLugt type correlator to an image subjected to coordinate transformation as preprocessing is already known. Fig. 3 shows VanderLugt with the conventional coordinate conversion function.
3 shows a block diagram of a type correlator. This method will be described with reference to the drawings. First, as a first step, a matched filter for a reference image is produced. In this step, the reference image is displayed on the liquid crystal television 303. The coherent light emitted from the laser 301 is expanded by the beam expander 302 and then converted into 2 by the beam splitter 305.
Branched into two. One of the light fluxes is the liquid crystal television 303 displaying the reference image and the coordinate conversion optical filter 304.
And is Fourier transformed by the coordinate conversion lens 307 to illuminate the writing surface of the liquid crystal light valve 308. In this way, the coordinate conversion intensity distribution image of the reference image is displayed on the liquid crystal light valve 308. The other light beam split by the beam splitter 305 is reflected by the mirror 306, the beam splitter 309, and the polarization beam splitter 310, and then irradiates the reading surface of the liquid crystal light valve 308 to convert the coordinate conversion intensity distribution image into a coherent image. To do. And
This coherent image is a polarization beam splitter 310.
Through the photographic dry plate 312 as a signal light at the time of hologram production.
Irradiate. At this time, the light flux that has simultaneously transmitted through the beam splitter 309 passes through the shutter 313 in the open state, is reflected by the mirror 314, and illuminates the photographic dry plate 312 as reference light during hologram production. At this time, the signal light and the reference light irradiate the photo dry plate 312 at a predetermined angle to form a hologram on the photo dry plate 312. Of course, the liquid crystal light valve 308 is arranged on the front focal plane of the Fourier transform lens 311, and the photographic dry plate 312 is arranged on the rear focal plane of the Fourier transform lens 311. The photographic dry plate 312 on which the hologram is formed in this way is removed and developed, and after development, it is placed in the original position again. The photographic dry plate 312 on which this hologram is recorded and developed is called a matched filter.

Next, in the second step, correlation processing is actually performed. The description of the same parts as those in the first step will be omitted or simplified. In this step, the correlated image is displayed on the liquid crystal television 303. Similar to the first step, the coordinate conversion intensity distribution image of the correlated image is displayed on the liquid crystal light valve 3.
The image is read out at 08, the image is read out by the Fourier transform lens 311, and the photographic dry plate 312, which is a matched filter, is irradiated. At this time, unlike the first step, the shutter 313 is in the closed state and the reference light does not irradiate the photographic dry plate 312. The light transmitted through the photographic dry plate 312, which is a matched filter, is converted into the Fourier transform lens 315.
By performing the Fourier transform again in step 1, the correlation peak representing the correlation coefficient between the reference image and the correlated image can be obtained on the light receiving element 316 arranged on the conversion surface. Here, the photographic dry plate 312 is arranged on the front focal plane of the Fourier transform lens 315, and the light receiving element 316 is arranged on the rear focal plane.

[0009]

However, according to the above method, since a photographic plate is usually used as a medium for recording a hologram as a matched filter, there are the following problems. First of all, it is necessary to form the hologram on the photographic plate, then remove it and develop it, which requires a lot of labor and time. Secondly, when the photographic dry plate is developed and then set back to the original position, it is very troublesome and difficult to adjust the photographic plate to the original position. In particular, this is because not only the center of the hologram should be aligned with the optical axis, but also the hologram must be set so that it does not rotate or tilt. Thirdly, when the reference image is changed, a matched filter is newly made, or
Alternatively, the reference image must be replaced with one that has been prepared in advance, and the reference image cannot be changed in real time or at high speed. For the above reasons, it has been impossible to construct a pattern recognition device having a coordinate conversion function capable of real-time operation at a practical level.

Another problem is that, in a hologram formed on a photographic dry plate, the angle between the signal light and the reference light is usually as large as several tens of degrees, and therefore the interval between several hundreds [lp / mm] and interference stripes. Is very narrow. Therefore, at the stage of making a matched filter, it is easily affected by vibration and wind,
If the interference fringes are shaken by them, an accurate hologram cannot be recorded and the pattern recognition ability is deteriorated.

[0011]

In order to solve the above-mentioned problems, the present invention sets at least one reference image including a desired target and at least one newly input correlated image into desired coordinate systems. An optical coordinate transformation unit for obtaining a transformed coordinate transformation image, and a joint transformation correlation for obtaining a correlation coefficient between the coordinate transformation image of the reference image and the coordinate transformation image of the correlated image obtained in the optical coordinate transformation unit. The optical coordinate transformation unit holds the two-dimensional reference image and the correlated image, at least one coherent light source, the reference image and the correlated image. At least one input image spatial light modulator, at least one coordinate conversion optical filter that is arranged so as to overlap the input image spatial light modulator, and at least one lens, The joint transform correlator unit transforms each coordinate transform image of the reference image and the correlated image obtained in the optical coordinate transform unit into a coordinate transform intensity distribution image, and transforms each coordinate transform intensity distribution image into coordinate transform. Means for displaying on the image spatial light modulator, means for converting each of the coordinate conversion intensity distribution images displayed on the coordinate conversion image spatial light modulator into a coherent image, and Fourier transforming the coherent image using a lens. Means for obtaining a joint Fourier transform image of the coordinate transform intensity distribution image, and converting the joint Fourier transform image into a Fourier transform intensity distribution image, and transforming the Fourier transform intensity distribution image into a Fourier transform image spatial light modulator. A means for displaying and the Fourier transform intensity distribution image displayed on the spatial light modulator for Fourier transform image using coherent light And the reading means,
Means for converting a correlation output image obtained by Fourier transforming the read Fourier transform intensity distribution image again using a lens, and means for converting the correlation signal into a signal by using an image pickup device or a light receiving element. The reference image and the correlated image have a structure including means for respectively obtaining two-dimensional correlation coefficients.

[0012]

In the optical pattern recognition device having the coordinate conversion function configured as described above, the coordinate system has a coordinate system that is invariant to a desired change such as rotation or size change in the optical coordinate conversion section. Optical conversion using a conversion optical filter allows pattern recognition that is invariant to such changes in the correlated image. The present invention also provides Va
Unlike the nderLugt type correlator, it is based on the joint transformation type correlator, so changing the coordinate transformation optical filter to change the type of coordinate transformation or replacing the reference image is done simply by using the reference image or the coordinate transformation optical filter. It only needs to be changed, and there is no need to re-record, develop, and replace the matched filter to adjust the optical axis, so it is extremely easy and fast. Moreover, adjustment of the optical axis in the optical system of the entire pattern recognition apparatus is much easier than that of the VanderLugt type correlator. Therefore, the influence of the vibration of the device or the fluctuation of air is reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of an optical pattern recognition apparatus having a coordinate conversion function according to the present invention. As a configuration of the optical coordinate conversion unit, the means for obtaining the two-dimensional reference image and the correlated image is the first input image capturing device 2
And a first image processing device 42 and an image memory device 43. At least one coherent light source is a first coordinate conversion laser 5 and a first coordinate conversion beam expander 6, and the reference image and The at least one input image spatial light modulator that holds the correlated image is the first input image electrically-writing spatial light modulator 3, and is the input image spatial light modulator. The at least one coordinate conversion optical filter arranged in a stack is the coordinate conversion optical filter array 44.
And at least one lens is the coordinate conversion lens array 47. As the configuration of the joint conversion correlator unit, each coordinate conversion image of the reference image and the correlated image obtained in the optical coordinate conversion unit is converted into a coordinate conversion intensity distribution image, and each coordinate conversion intensity distribution image is The means for displaying on the coordinate-converted image spatial light modulator comprises a mask 48 and a first coordinate-converted optical writing type spatial light modulator 13, each of which is displayed on the coordinate-converted image spatial light modulator. The means for converting the coordinate transformation intensity distribution image into a coherent image is composed of a Fourier transform laser 101, a Fourier transform beam expander 102, and a first Fourier transform polarization beam splitter 103, and the coherent image is Fourier transformed using a lens. The means for transforming to obtain the joint Fourier transform image of the coordinate transform intensity distribution image comprises a first Fourier transform lens 104, The means for converting the joint Fourier transform image into a Fourier transform intensity distribution image and displaying the Fourier transform intensity distribution image on the Fourier transform image spatial light modulator comprises a Fourier transform optical writing type spatial light modulator 105. The means for reading the Fourier transform intensity distribution image displayed on the Fourier transform image spatial light modulator using coherent light is a correlation laser 2
01, a beam expander for correlation 202, and a polarization beam splitter for correlation 203, a correlation output image obtained by Fourier transforming the read Fourier transform intensity distribution image again using a lens The means for converting into a correlation signal using the second Fourier transform lens 204 and the light receiving element 205,
The means for performing signal processing on the correlation signal to obtain the two-dimensional correlation coefficients of the reference image and the correlated image respectively comprises an identification circuit 206.

First, although omitted in FIG. 1, the reference object, which is a database as a recognition reference, is a correlated object 1.
The image is picked up by the first input image pickup device 2 as a two-dimensional reference image, and the image is stored in the image memory device 43 via the first image processing device 42. Next, similarly, the correlated object 1 to be recognized is photographed by the first input image capturing device 2 to form a two-dimensional correlated image, and this correlated image is stored in the image memory device 43 first. The reference image thus prepared is combined by the first image processing device 42 and displayed on the first input image electric writing type spatial light modulator 3. Here, the reference image and the correlated image are, for example, as shown in FIG.
As shown in FIG. 5, the predetermined distance L is added so that they do not overlap, and they are combined.

The coordinate conversion optical filter array 44 is a computer generated hologram (C).
GH), two coordinate conversion optical filters are arranged at a predetermined distance L. In the coordinate conversion, if the relative positional relationship between the coordinate conversion optical filter and the image to be converted is different, different coordinate converted images will be obtained even if the same image is subjected to coordinate conversion. for that reason,
The distance between the two coordinate conversion optical filters is set so that the relative positional relationship between the reference image and the coordinate conversion optical filter relative to the reference image is the same as the relative positional relationship between the correlated image and the coordinate conversion optical filter corresponding thereto. It must be equal to the distance L between the reference image and the correlated image.

The coherent light emitted from the first coordinate conversion laser 5 is expanded into a parallel light beam having a predetermined beam diameter by the first coordinate conversion beam expander 6, and the correlated image and the reference image are obtained. By illuminating the displayed electric writing type spatial light modulator 3 for the first input image,
Convert these images into coherent images. Then, these coherent images pass through the respective coordinate conversion optical filters on the coordinate conversion optical filter array 44 which is arranged so as to overlap with the first input image electric writing type spatial light modulator 3, and the coordinate conversion lens The Fourier transform is performed by each coordinate transformation lens of the array 47, so that the coordinate transformation image transformed into a desired coordinate system is obtained on the transformation surface. Then, the mask 48 disposed immediately in front of the first coordinate-writing optical writing type spatial light modulator 13 is provided with a hole so that, for example, only each + first-order coordinate conversion image is transmitted. As a result, unnecessary DC bias components, higher-order coordinate conversion images, etc. are blocked, and only the necessary coordinate conversion images of the reference image and the correlated image are transmitted and the first coordinate conversion optical writing type spatial light is transmitted. The writing surface of the modulator 13 is illuminated. As a result of the above, the coordinate-converted images of the correlated image and the reference image are converted into intensity distributions, and as the coordinate-converted intensity distribution images, the distance L is set on the first coordinate-writing optical writing type spatial light modulator 13.
It is displayed far apart. There are many kinds of first optical writing type spatial light modulators for coordinate conversion 13, but in the present embodiment, a reflection type liquid crystal light valve whose light modulating material is a ferroelectric liquid crystal is used. Describe.

Here, the first input image electric writing type spatial light modulator 3 and the coordinate conversion optical filter array 44 are arranged on the front focal plane of the coordinate conversion lens array 47 so as to overlap each other, and the first focal plane is formed on the rear focal plane. The coordinate writing optical writing type spatial light modulator 13 is arranged. Further, each coordinate conversion lens is arranged at a distance L corresponding to the positions of two images to be converted, as in the case of the coordinate conversion optical filter.

The coherent light emitted from the Fourier transform laser 101 is expanded into a parallel light beam having a predetermined beam diameter by the Fourier transform beam expander 102, and then the first Fourier transform polarization beam splitter 10 is used.
The light is reflected at 3 and irradiates the reading surface of the first optical writing type spatial light modulator for coordinate conversion 13 as the reading light. Here, the polarization direction of the readout light and the direction of the alignment of liquid crystal molecules (or the direction orthogonal thereto) aligned by the initialization of the first optical writing type spatial light modulator for coordinate conversion 13 are previously matched. Every other time, the polarization axis is perpendicular (or parallel) to the polarization direction of the reading light reflected by the first coordinate-writing optical writing spatial light modulator 13.
The image displayed on the first optical writing type spatial light modulator for coordinate conversion 13 can be read out as a positive image or a negative image by passing through the analyzer arranged so that. In this embodiment, the first Fourier transform polarization beam splitter 103 is used as an analyzer.

As described above, each coordinate transformation intensity distribution image displayed on the first coordinate writing optical writing type spatial light modulator 13 is transformed into a coherent image, and the first Fourier transform lens 104 performs the Fourier transform. By doing so, a joint Fourier transform image of each coordinate transform intensity distribution image of the reference image and the correlated image is formed on the transform surface. Therefore, the optical writing type spatial light modulator for Fourier transform 105 is provided on the conversion surface.
By arranging the writing surface of the above, the intensity distribution of the joint Fourier transform image of each coordinate transform intensity distribution image of the reference image and the correlated image can be converted into a Fourier transform intensity distribution image as an optical writing type spatial light modulator for Fourier transform. 105 is displayed. Also here, as the optical writing type spatial light modulator for Fourier transform 105, as in the first optical writing type spatial light modulator for coordinate transformation 13, a reflection type liquid crystal light valve using a ferroelectric liquid crystal is used. ing. The first optical writing type spatial light modulator for coordinate conversion 13 is provided on the front focal plane of the first Fourier transform lens 104.
On the back focal plane of the optical writing type spatial light modulator for Fourier transform 1
Place 05.

The coherent light emitted from the correlation laser 201 is expanded into a parallel light beam having a predetermined beam diameter by the correlation beam expander 202, and then reflected by the correlation polarization beam splitter 203 to be Fourier light as read light. The reading surface of the conversion optical writing type spatial light modulator 105 is illuminated. Here, as in the case of the first optical writing type spatial light modulator for coordinate conversion 13, the Fourier transform intensity distribution image displayed on the optical writing type spatial light modulator for Fourier transform 105 becomes a coherent image. To be converted. However, the polarization beam splitter 203 for correlation is used as an analyzer. This read coherent image is Fourier transformed by the second Fourier transform lens 204,
A correlation output image including a correlation peak is formed on the light receiving element 205 arranged on the conversion surface. The light receiving element 205 receives only the correlation peak in the correlation output image and converts it into a correlation signal. The correlation signal is input to the discrimination circuit 206, the correlation peak intensity is measured, and the correlation coefficient between the correlated image and the reference image is output. Here, the Fourier transform optical writing type spatial light modulator 105 is arranged on the front focal plane of the second Fourier transform lens 204, and the light receiving element 205 is arranged on the rear focal plane.

In order to perform the strict Fourier transform, it is preferable to dispose the image to be Fourier transformed on the front focal plane of each lens which performs the Fourier transform or between the lens and the rear focal plane. Then, a Fourier transform image is formed on the back focal plane of the lens. Therefore, in the present embodiment, an image to be Fourier transformed is arranged on the front focal planes of the coordinate transformation lens array 47, the first Fourier transform lens 104, and the second Fourier transform lens 204, and an image Fourier transformed on the rear focal plane. Is being received.

In this embodiment, a reflective liquid crystal light using a ferroelectric liquid crystal is used as the first coordinate conversion optical writing type spatial light modulator 13 and Fourier transform optical writing type spatial light modulator 105. It uses a valve. When TN liquid crystal, which is a well-known light modulation material, is used, gradation expression is possible, but the resolution is low at about 30 [lp / mm],
There is a problem that the operation speed is slow at the video rate (30 Hz). In order to solve this problem, in this embodiment, a ferroelectric liquid crystal was used as the light modulation material instead of the TN liquid crystal.
As a result, the liquid crystal light valve using the ferroelectric liquid crystal has a resolution of about 100 [lp / mm] and
The operation speed also shows a very excellent characteristic of about several kHz. However, a point to be noted here is that a liquid crystal light valve using a ferroelectric liquid crystal normally stores a binary image of a written image because the liquid crystal itself has bistability. Therefore, in this embodiment, since the coordinate transformation intensity distribution image and the Fourier transform intensity distribution image are binarized and stored, they are the binarized coordinate transformation intensity distribution image and the binarized Fourier transform intensity distribution image. Of course, as the other light modulating material, a material using an electro-optic crystal such as a BSO crystal in addition to the liquid crystal can be considered. Further, it goes without saying that the principle is the same in the case of the transmissive optical writing type spatial light modulator instead of the reflective type. Further, instead of using the spatial light modulator of the optical writing type, it is also possible to use the image pickup device and the spatial light modulator of the electric writing type in combination. For this method,
More on this later.

Next, the structure and operation of the reflection type liquid crystal light valve, which is used as the optical writing type spatial light modulator in this embodiment, in which the light modulating material is the ferroelectric liquid crystal, will be described. The difference from the conventional liquid crystal light valve is that a ferroelectric liquid crystal having clear bistability between light transmittance or light reflectance and an applied voltage is used as a liquid crystal layer. Figure 5
It is sectional drawing which shows the structure of the liquid crystal light valve which used the ferroelectric liquid crystal. Transparent substrates 131a and 131b such as glass or plastic for sandwiching liquid crystal molecules are provided with transparent electrode layers 132a and 132b on their surfaces, and silicon monoxide is inclined at an angle in the range of 75 to 85 degrees from the normal direction of the transparent substrate. Orientation film layers 133a and 133b vapor-deposited are provided.
The transparent substrates 131a and 131b have their alignment film layers 133a,
The ferroelectric liquid crystal layer 134 is sandwiched between the 133b sides so as to face each other while controlling the gap via the spacer 139. Further, the photoconductive layer 135, the light shielding layer 136, and the dielectric mirror 13 are provided on the transparent electrode layer 132a on the light writing side.
7 is laminated on the alignment film layer 133a, and antireflection coating layers 138a and 138b are formed on the cell outer surfaces of the transparent substrate 131a on the writing side and the transparent substrate 131b on the reading side.

In the above structure, when the visible light reflectance of the dielectric mirror 137 is sufficiently high and the influence of the reading light on the photoconductive layer 135 is extremely small, the light shielding layer 136 can be omitted. Further, when the reflectance of the photoconductive layer 135 with respect to the read light is sufficiently large, and the read light is sufficiently small and the influence of the read light on the photoconductive layer 135 is extremely small, the dielectric mirror 137 can be omitted. . However, in this embodiment, since the area of the normal coordinate conversion intensity distribution image is small and the utilization efficiency of the readout light is low, the intensity of the readout light is preferably high. Therefore, it is preferable that the first coordinate conversion optical writing type spatial light modulator 13 for displaying the coordinate conversion intensity distribution image has the light shielding layer 136 and the dielectric mirror 137. On the contrary, since the area of the Fourier transform intensity distribution image is not so small, the reading light may be weak. Therefore, it is often sufficient that the Fourier transform optical writing type spatial light modulator 105 for displaying the Fourier transform intensity distribution image does not have the light shielding layer 136 or the dielectric mirror 137.

Next, a method of initializing the liquid crystal light valve having the above structure will be described. The first method is to irradiate the entire writing surface of the liquid crystal light valve with light once and superimpose a pulse voltage, a DC bias voltage or an AC voltage of 100 Hz to 50 kHz which is sufficiently higher than the maximum value of the threshold voltage at the time of light. The generated DC bias voltage is applied to the transparent electrode layers 132a and 132a.
By applying during b, the ferroelectric liquid crystal molecules are aligned in a unidirectional stable state and the state is stored in the memory. The second method is
Without light irradiation, pulse voltage or DC bias voltage that is sufficiently higher than the maximum threshold voltage in the dark, or 1
A DC bias voltage in which an AC voltage of 00 Hz to 50 kHz is superimposed is applied between the transparent electrode layers 132a and 132b to align the ferroelectric liquid crystal molecules in a unidirectional stable state, and the state is stored in the memory. Normally, the maximum value of the threshold voltage in the dark is larger than that in the light irradiation.

Further, the operation after the liquid crystal light valve is initialized as described above will be described. Without light irradiation, the threshold voltage is below the maximum value in the dark, and the threshold voltage is above the maximum value during the light irradiation.
While applying a DC bias voltage on which an AC voltage of 50 kHz is superimposed between the transparent electrode layers 132a and 132b, an image is optically written with a laser beam or the like. Carriers are generated in the photoconductive layer 135 in the region irradiated with the laser, and the generated carriers drift toward the electric field due to the applied voltage. As a result, the threshold voltage is lowered, and the carriers are not irradiated in the region irradiated with the laser. An applied voltage with a polarity opposite to that of the threshold voltage is applied, and the ferroelectric liquid crystal undergoes inversion of molecules due to the inversion of spontaneous polarization, and shifts to the other stable state. It is processed and stored.

The binarized and stored image is irradiated with linearly polarized read-out light whose polarization axis is aligned with the direction of the alignment of liquid crystal molecules aligned by the initialization (or the direction perpendicular thereto), and dielectric. A positive state or a negative state can be read by passing an analyzer arranged such that the polarization axis is perpendicular (or parallel) to the polarization direction of the reflected light from the body mirror 137. In the embodiment shown in FIG. 1, a polarization beam splitter is used instead of the light detection.

The threshold for binarizing an image is adjusted by adjusting the pulse voltage value or pulse width applied between the transparent electrode layers 132a and 132b, the frequency of the AC voltage or the value of the DC bias voltage. Can be changed. Further, by adjusting the laser power to change the light intensity applied to the writing surface, substantially the same effect as when the threshold value is changed can be obtained.

Next, the first optical writing type spatial light modulator for coordinate conversion 13 and the first optical writing type spatial light modulator for Fourier transform 105.
As a method of driving a liquid crystal light valve using the above ferroelectric liquid crystal, the driving method will be described. From the initialization method and the operating principle already described, it is necessary to drive as follows. Basically, it is necessary that the writing light irradiation time for writing the writing light on the writing surface of each liquid crystal light valve and the writing voltage application time for the liquid crystal light valve are at least equal to each other for a predetermined time. is there. When a number of liquid crystal light valves are connected in series, the drive voltage applied to each liquid crystal light valve,
The irradiation time of the reading light and the writing light to the liquid crystal light valve must be operating in synchronization.

FIG. 6 shows a first coordinate-writing optical writing type spatial light modulator 13 and a Fourier transforming optical writing type spatial light modulator 10.
5 and a drive voltage applied to the laser 5, and a Fourier transform laser 101 for writing and reading to and from each optical writing type spatial light modulator.
An example of the relationship between the output light intensity of the correlation laser 201 and is shown. However, the writing of the coordinate-converted image of the correlated image or the reference image into the first coordinate-writing optical writing type spatial light modulator 13 will be described later. When the writing pulse is applied to the spatial light modulator 13, it is assumed that the coordinate-converted images are always irradiated on the writing surface. First, as shown in FIG. 6A, a driving voltage such that an erase pulse 150, a write pulse 151, and a zero voltage 152 are sequentially repeated is applied to the first coordinate-writing optical writing spatial light modulator 13. Is being applied. Erase pulse 150
The image stored in the first optical writing type spatial light modulator for coordinate conversion 13 is erased and initialized by the writing pulse 1
The operation of newly storing the image irradiated on the writing surface at 51 and reading the stored image in the state of zero voltage 152 is repeated. The pulse voltages of the erase pulse 150 and the write pulse 151 satisfy the conditions described in the above description of the operation principle.

With the above drive voltage, new binary coordinate conversion intensity distribution images are successively stored in the first coordinate-writing optical writing type spatial light modulator 13. Then, as shown in FIG. 6B, the state where the driving voltage applied to the first optical writing type spatial light modulator for coordinate conversion 13 is zero voltage 152, and the first coordinate conversion optical writing device The output of the Fourier transform laser 101 is modulated so that the state of the laser irradiation 153 for irradiating the reading light on the reading surface of the embedded spatial light modulator 13 is matched. As a result, new binarized coordinate conversion intensity distribution images stored in the first optical writing type spatial light modulator for coordinate conversion 13 are sequentially read out, and the Fourier transform laser 10 is read.
The joint Fourier transform image of the optical writing type spatial light modulator for Fourier transform 10 only during the laser irradiation 153 of 1
The writing surface of No. 5 is irradiated. Therefore, as shown in FIG. 6C, the write pulse 155 is applied to the Fourier transform optical writing type spatial light modulator 105 in synchronization with the period of the laser irradiation 153. Of course, immediately before the application of the write pulse 155, the optical writing type spatial light modulator for Fourier transform 1
An erase pulse 154 for initializing 05 is applied, and immediately after the write pulse 155, there is a zero voltage 156 and the image is read. As a result of the above, new binary binarized Fourier transform intensity distribution images are successively stored in the Fourier transform optical writing type spatial light modulator 105, and the stored binarized Fourier transform intensity distribution images have zero voltage. Laser irradiation of the laser 201 for correlation with the period of 156 15
By synchronizing with the period of 7 as shown in FIG. 6D, a correlation output image can be obtained during the period of laser irradiation 157 of the correlation laser 201.

If the first optical writing type spatial light modulator for coordinate conversion 13 and the first optical writing type spatial light modulator for Fourier transform 105 are used.
Does not have the light shielding layer 136 or the dielectric mirror 137,
The reading light affects the photoconductive layer 135. By utilizing this, it becomes possible to lower the applied voltage of the erase pulses 150 and 154. In other words, if the read light is not emitted only during the period corresponding to the zero voltage 152 or 156, but also during the period corresponding to the erase pulse 150 or 154, the laser beam is emitted even during initialization. Has been done. As a result, the threshold voltage of the first optical writing type spatial light modulator for coordinate conversion 13 and the first optical writing type spatial light modulator for Fourier transform 105 is lower in the light irradiation than in the dark. Therefore, the erase pulse 150 or 154
Initialization is possible even if the voltage of is lowered.

In addition, the light shielding layer 136 and the dielectric mirror 137.
Needless to say, when the influence of the read light on the photoconductive layer 135 is negligible, it is not necessary to modulate the read light as described above. However, even in that case, the zero voltage 152 of the first optical writing type spatial light modulator for coordinate conversion 13 and the optical writing type spatial light modulator for Fourier transform 10 as described above.
Synchronization of 5 write pulses 155 is required.

By applying the driving voltage shown above, the first optical writing type spatial light modulator for coordinate conversion 13 and the first optical writing type spatial light modulator for Fourier transform 105 have a frequency of 30 Hz to 2 Hz.
It was possible to drive at a high speed of kHz. In addition, since the image illuminated on the writing surface is binarized and stored, even if there are many noise components and they are normally buried in noise, adjusting the threshold value ensures that no noise components are present. It has become possible to obtain such images.

Next, the first input image electrically writing type spatial light modulator 3 used in the above embodiment will be described. As described above, when the liquid crystal light valve using the ferroelectric liquid crystal is used as the first coordinate-writing optical writing spatial light modulator 13 and the Fourier transform optical writing spatial light modulator 105, It became possible to operate at a very high speed of about 30 Hz to 2 kHz. However, when a liquid crystal television whose light modulation material is TN liquid crystal is used as the first input image electric writing type spatial light modulator 3, it can be operated only at a low speed of 30 Hz. The operation speed of the device is limited by the speed of the first electrically writing type spatial light modulator for input image 3. Therefore, in order to enable high-speed operation as the first electrically-written spatial light modulator for input image 3, the optical modulation material is an electro-optical ceramic such as PLZT, a magneto-optical material such as yttrium iron garnet, or a ferroelectric material. It is preferable to use an organic liquid crystal. Therefore, in this embodiment, as the first input image electric writing type spatial light modulator 3, an electric writing type spatial light modulator using a ferroelectric liquid crystal as an optical modulation material is used.

Further, also in the operation of the first electric image writing spatial light modulator for input image 3, the above-mentioned first coordinate writing optical writing spatial light modulator 13 and Fourier transform optical writing are performed. Needless to say, it is necessary to operate in synchronization with other spatial light modulators and lasers as in the case of the spatial light modulator 105. That is, the coordinate-converted images of the reference image and the correlated image displayed on the first input-image electrically writing spatial light modulator 3 are transferred to the first coordinate-writing optical writing spatial light modulator 13. In order to store the first input image during the period of the zero voltage 152 and the erasing pulse 150 in the driving voltage applied to the first optical writing type spatial light modulator for coordinate conversion 13 shown in FIG. 6A. The electric writing type spatial light modulator 3 for an input image is erased while the image on the electric writing type spatial light modulator 3 is written and a new image is written.
Must hold the image to be displayed on. Therefore,
A method of driving each pixel of the first electric image writing spatial light modulator 3 for an input image is an active method represented by a TFT (Thin Film Transistor) method in which a transistor is formed for each pixel to operate. . And zero voltage 152
At the same time as the start of the period, a signal for erasing the image displayed in each pixel on the first electric writing type spatial light modulator for input image 3 is added, and immediately after that, an image for displaying a new image. A signal is applied to each pixel. As a result, the first input image electric writing type spatial light modulator 3 can also operate at high speed in synchronization with other spatial light modulators.

In the normal correlation processing that does not use coordinate transformation, when the correlated object is rotated about 10 degrees with respect to the reference object or the size is different by 20 to 30%, the intensity of the correlation peak is greatly reduced. And I could not recognize it correctly. However, in the present invention described above, by using a filter for converting (1nr, θ) coordinates as the coordinate conversion optical filter, the rotation angle can be 360 degrees, and the size change can be changed. Even when the change is about 50%, the pattern can be recognized without any problem, and the pattern recognition that is invariant to the rotation and the change in the size is possible.
It was also possible to measure the amount of change in the rotation angle and the size from the position where the correlation peak appears. Further, even when a coordinate conversion optical filter for converting to another coordinate system is used, similarly, it is possible to perform pattern recognition that is invariant in size and rotation in correspondence with the coordinate conversion used.

Regarding the recognition speed, when a spatial light modulator using a ferroelectric liquid crystal as a light modulation material is used, the spatial light modulator can operate at about 30 Hz to 2 kHz.
The pattern recognition device as a whole was capable of high-speed operation of about 30 Hz to 2 kHz. Furthermore, in the present invention, Va
Since the joint conversion type correlator is used instead of the nderLugt type correlator, it is possible to easily recognize the pattern without developing the photographic plate or setting the photographic plate after development. Furthermore, if the reference object is stored in the image memory device 43 in advance, the reference image can be changed easily and at high speed. Further, since a spatial light modulator having a higher resolution than that of a photographic dry plate is not required, the influence of vibration and fluctuation of air is small, and the optical axis adjustment of the optical system is easy.

FIG. 7 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. The parts having the same functions as those of the embodiment in FIG. 1 are designated by the same reference numerals, and the correspondence with the claims and the description thereof are omitted or simplified. There is no difference in the configuration of the optical coordinate conversion unit from that of the above embodiment. Regarding the part different from the embodiment in the configuration of the joint conversion correlator unit, each coordinate conversion image of the reference image or the correlated image obtained in the optical coordinate conversion unit is converted into a coordinate conversion intensity distribution image, The means for displaying each coordinate conversion intensity distribution image on the coordinate conversion image spatial light modulator comprises a first coordinate conversion image pickup device 9, a mask 48, and a coordinate conversion electrically writing type spatial light modulator 14. The means for converting the joint Fourier transform image into a Fourier transform intensity distribution image and displaying the Fourier transform intensity distribution image on the Fourier transform image spatial light modulator is a Fourier transform imaging device 106 and a Fourier transform electrically writing type space. It comprises an optical modulator 107.

The part up to the point where the coordinate conversion image of the correlated image and the reference image is obtained on the conversion surface is the same as in the embodiment shown in FIG. Each coordinate conversion image obtained on the conversion surface is received by the first coordinate conversion image pickup device 9 and converted into an electric signal. By inputting the electric signal to the coordinate-writing electric writing type spatial light modulator 14, the coordinate-converting intensity distribution images are separated by a predetermined distance L on the coordinate-converting electric writing type spatial light modulator 14. Is displayed. The coherent light emitted from the Fourier transform laser 101 is applied to the coordinate-writing electrical writing type spatial light modulator 14 after the luminous flux is expanded by the Fourier transform beam expander 102. As a result, each coordinate-transformed intensity distribution image is transformed into a coherent image, which is Fourier-transformed by the first Fourier transform lens 104 to obtain a joint Fourier transform image on the transform surface. Therefore, the joint Fourier transform image is received by the Fourier transform imaging device 106, converted into an electric signal, and the electric signal is input to the Fourier transform electric writing type spatial light modulator 107. A Fourier transform intensity distribution image of the joint Fourier transform image can be displayed on the embedded spatial light modulator 107. The coherent light emitted from the correlation laser 201 is expanded by the correlation beam expander 202 and then radiated to the Fourier transform electric writing type spatial light modulator 107. As a result, the Fourier transform intensity distribution image is converted into a coherent image, and the second Fourier transform lens 204 performs a Fourier transform on the image to obtain a correlation output image on the transform surface. The following processing is the same as that of the above-mentioned embodiment, and therefore its explanation is omitted.

The electric writing type spatial light modulators 14 and 107 for the coordinate conversion and the Fourier transform used here are considered to be operated at a high speed, and the electric writing for the first input image in the previous embodiment is considered. As in the case of the type spatial light modulator 3, it is preferable to use an electro-optical ceramic such as PLZT, a magneto-optical material such as yttrium iron garnet, or a ferroelectric liquid crystal as the light modulating material. Therefore, in this embodiment, as the electric writing type spatial light modulators 14 and 107 for the coordinate conversion and the Fourier transform, the electric writing type spatial light modulator whose light modulating material is the ferroelectric liquid crystal is used. In this case, since the ferroelectric liquid crystal has bistability, the displayed image is usually binarized. Therefore, the coordinate transformation intensity distribution image or the Fourier transformation intensity distribution image becomes a binarized coordinate transformation intensity distribution image or a binarized Fourier transform intensity distribution image.

As described above, when the electric writing type spatial light modulators for which the light modulating material is the ferroelectric liquid crystal is used as the electric writing type spatial light modulators 14 and 107 for the coordinate conversion and the Fourier transform, A binarized coordinate transformation intensity distribution image or a binarized Fourier transform intensity distribution image is obtained by directly inputting the electric signals output from the first coordinate transformation imaging device 9 and the Fourier transformation imaging device 106. However, in the case of using the ordinary electric writing type spatial light modulator, since they can express gradation, it is necessary to binarize the electric signal before inputting to the electric writing type spatial light modulator. There is.

Also in this embodiment, similarly to the above-mentioned embodiment, the pattern recognition which is invariant with respect to the size and rotation of the correlated image can be performed at high speed. By the way, in the embodiments described above, there is one reference image and one correlated image. Therefore, when recognizing a large number of types of images, it is necessary to rewrite the reference images one after another to perform the recognition, and there is a problem that the recognition takes time accordingly. Therefore, in order to solve this problem, a method of making a plurality of reference images and performing a correlation process with many reference images at one time has been considered. FIG. 8 shows an example in which a correlated image and a plurality of reference images are arranged. In this way, a plurality of reference images are arranged around the circumference of one correlated image. By arranging the coordinate conversion optical filter in the coordinate conversion optical filter array 44, the coordinate conversion lens in the coordinate conversion lens array 47, and the hole in the mask 48 in correspondence with the position of each reference image or correlated image. The pattern recognition can be performed in the same manner as in the above embodiment. Here, since there are a plurality of pairs of correlation peaks obtained by making a plurality of reference images, it is necessary to arrange a plurality of light receiving elements 205 corresponding to the positions where the respective correlation peaks appear and measure the intensity of the correlation peaks. It goes without saying that it must be done. Further, although the reference image is pluralized in the above description,
On the contrary, it goes without saying that the principle is the same even if a plurality of correlated images are made and pattern recognition is performed with respect to one reference image. Therefore, the case where a plurality of reference images are provided will be described below as an example.

Generally, when a plurality of reference images are used as described above, the S / N ratio is greatly reduced due to the decrease in the intensity of each correlation peak and the increase in the noise component. Therefore, in order to solve such a drawback, we have already proposed a joint transform correlator having a feedback system. This is to input each two-dimensional correlation coefficient of at least one correlated image and at least one reference image obtained as a result of the correlation processing into a linear or non-linear transfer function in an ordinary joint transform correlator. A feedback system that substantially changes the intensity of light that passes through each reference image corresponding to each correlation coefficient according to the output of the transfer function is configured. And with this configuration,
It is shown that pattern recognition with good S / N is possible even with a plurality of reference images.

Also in the present invention, a feedback system similar to the above can be provided. FIG. 9 shows an example in which a feedback system is added to the optical pattern recognition device having the coordinate conversion function according to the present invention. Claim 2
As the configuration of the feedback unit of, the normalization circuit that normalizes the correlation coefficient with the maximum correlation coefficient is the feedback control circuit 208, and is the input image spatial light modulator or the coordinate conversion image spatial light modulation. The mask spatial light modulator arranged immediately before or after the device is a feedback mask 207, and the transmittance of a portion corresponding to each of the reference images or the coordinate conversion intensity distribution images on the mask spatial light modulator. Alternatively, the means for changing the reflectance in a linear or non-linear relationship based on the correlation coefficient normalized by the normalization circuit is composed of the feedback control circuit 208. The difference from the embodiment shown in FIG. 1 is that the number of reference images is increased, the number of coordinate conversion optical filters, coordinate conversion lenses, and light-receiving elements corresponding to the reference images are increased, and each binarized coordinate conversion intensity distribution image. Immediately after the first optical writing type spatial light modulator for coordinate conversion 13 for storing and displaying, a feedback mask 207 for changing the light intensity with which the reading light illuminates each binarized coordinate conversion intensity distribution image. That is, a feedback control circuit 208 for arranging and controlling the feedback mask 207 according to the correlation coefficient from the identification circuit 206 is provided.

Next, the actual operation will be described. The method of storing a plurality of binarized coordinate conversion intensity distribution images in the first coordinate-writing optical writing type spatial light modulator 13 has already been described, and is therefore omitted. The coherent light emitted from the Fourier transform laser 101 is reflected by the first Fourier transform polarization beam splitter 103 as in the case of FIG.
The reading light is transmitted through the feedback mask 207 to illuminate the reading surface of the first coordinate-writing optical writing spatial light modulator 13. In the initial state, the feedback mask 207 is in a completely transparent state. Then, the reflected light on the reading surface passes through the feedback mask 207 again, and then through the first Fourier transform polarization beam splitter 103, is Fourier transformed by the first Fourier transform lens 104, and is written in the Fourier transform optical writing. A joint Fourier transform image is formed on the die spatial light modulator 105, and a binarized Fourier transform intensity distribution image is stored. Here, it should be noted that the read light is transmitted through the feedback mask 207 twice. That is, when the transmittance of the feedback mask 207 is set to x, the binarized coordinate transformation intensity distribution image is set to X.
^{This is} because it corresponds to masking in ² . The procedure until the stored binarized Fourier transform intensity distribution image is read and the correlation coefficient is obtained is the same as in the case of FIG. However, naturally, a plurality of correlation coefficients are output from the discrimination circuit 206 to the feedback control circuit 208.

The correlation coefficient corresponding to each reference image input to the feedback control circuit 208 is normalized by the maximum correlation coefficient and then changed according to the result of the preset correlation processing or the correlation processing. It is input to the feedback transfer function and the rate of masking each reference image is determined. The transmittance of the portion of each reference image of the feedback mask 207 corresponding to the binarized coordinate transformation intensity distribution image is changed according to the ratio. As a matter of course, this transmittance is considered to be transmitted through the feedback mask 207 twice. Then, in that state, the feedback loop of performing the same correlation processing again is repeated. By this feedback, even when the reference image becomes plural in the present invention,
Pattern recognition with good S / N became possible. In the above embodiment, the feedback mask 207 is used to change the light intensity for irradiating each binarized coordinate conversion intensity distribution image, but in order to change the light intensity for irradiating the original reference image, the first It goes without saying that it may be arranged immediately before or after the electrically writing type spatial light modulator 3 for input image.

Further, various feedback transfer functions can be considered. Examples of linear functions and non-linear functions include saturated functions such as step functions and sigmoid functions, and combinations thereof. By changing the nonlinearity of the feedback transfer function and the type and shape such as the threshold value, the recognition characteristics of the pattern recognition apparatus of the present invention are greatly changed. Therefore, by presetting an appropriate feedback transfer function or changing the shape and type of the feedback transfer function according to the result of the correlation processing, pattern recognition with higher S / N can be performed at higher speed.

Further, each reference image and the correlated image itself,
Alternatively, the area of each coordinate conversion intensity distribution image of the reference image or the correlated image can be standardized by using the feedback mask 207 or another optical mask. When the number of reference images is large, the areas of the reference images, the correlated images, or the coordinate conversion intensity distribution images thereof are different. Therefore, there is a problem that the larger the area, the easier the recognition. Therefore, the area or the amount of light that substantially transmits and reflects them instead of the area is measured. Based on the measured value, the feedback mask 207 or another optical mask changes the light intensity that substantially transmits or reflects each reference image, the correlated image, or each coordinate conversion intensity distribution image thereof. This makes it possible to equalize the intensities of the Fourier transform images of the coordinate transformation intensity distribution images. This normalizing means corresponds to making the intensity of the autocorrelation peak of each reference image equal,
It was confirmed that the recognition ability with multi-reference images was improved with or without the feedback system.

FIG. 10 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. This shows a method of displaying a correlated image and a reference image on one optical writing type spatial light modulator. The parts having the same functions as those of the embodiment in FIG. Further, the processing after displaying the coordinate conversion intensity distribution image on the first coordinate conversion optical writing type spatial light modulator 13 is the same as that of the embodiment described so far, and therefore the description thereof is omitted. The optical coordinate conversion unit differs from the embodiment shown in FIG. 1 in that the means for obtaining the two-dimensional reference image and the correlated image are a first imaging lens 10 and a second imaging lens. 30 and an input image beam splitter 46, and at least one input image spatial light modulator holding the reference image and the correlated image is a first input image optical writing type spatial light. The modulator 11.

The correlated object 1 is the first imaging lens 10
Is transmitted through the input image beam splitter 46 to form an image on the writing surface of the first input image optical writing type spatial light modulator 11, and as a correlated image, the first input image optical writing type It is displayed on the spatial light modulator 11. Similarly, the reference object 21 is also imaged on the writing surface of the first input image optical writing type spatial light modulator 11 by the second image forming lens 30 through the input image beam splitter 46. , Is displayed as a reference image. Here, it goes without saying that the optical system is adjusted so that the correlated image and the reference image are imaged at a predetermined distance L from each other. Here, the following configuration will be described in the case where a reflection type liquid crystal light valve is used as the first input image light writing type spatial light modulator 11.

The coherent light emitted from the first coordinate conversion laser 5 is expanded by the first coordinate conversion beam expander 6 and then reflected by the first coordinate conversion polarization beam splitter 12. The coordinated image and the reference image are converted into a coherent image by irradiating the read surface of the first input image optical writing type spatial light modulator 11 through the coordinate conversion optical filter array 44. Here, the coordinate conversion optical filter array 44 and the first input image optical writing type spatial light modulator 11 are arranged in an overlapping manner. This coherent image again passes through the coordinate conversion optical filter array 44 and the first coordinate conversion polarization beam splitter 12, and is then Fourier transformed by the coordinate conversion lens array 47 to write the first coordinate conversion light. Type spatial light modulator 13
Each coordinate transformation intensity distribution image is displayed on the top. Subsequent processing is the same as that of the above-described embodiment, so the description thereof will be omitted.

FIG. 11 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. This shows a method in which the reference image and the correlated image are displayed on different optical writing type spatial light modulators, respectively, and then the coordinates are converted separately. The parts having the same functions as those of the embodiment in FIG. Further, after the coordinate conversion intensity distribution image is displayed on the first coordinate conversion optical writing type spatial light modulator 13, the explanation is omitted because it is the same as the embodiment described so far.
The optical coordinate conversion unit differs from the embodiment shown in FIG. 1 in that the means for obtaining the two-dimensional reference image and the correlated image are a first imaging lens 10 and a second imaging lens. 30 and at least one coherent light source includes a first coordinate conversion laser 5, a first coordinate conversion beam expander 6, a first coordinate conversion polarization beam splitter 12, and a second coordinate conversion laser. 25, a second coordinate conversion beam expander 26, and a second coordinate conversion polarization beam splitter 32, and at least one input image spatial light modulation holding the reference image and the correlated image. The first optical image writing spatial light modulator 11 and the second optical input image writing spatial light modulator 31 are arranged at least on the input image spatial light modulator. One coordinate conversion optical filter Data includes a first coordinate transformation optical filter 4 is a second coordinate conversion optical filters 24, at least one lens includes a first coordinate transformation lens 7 is a second coordinate transformation lens 27.

The correlated object 1 is the first imaging lens 10
Of the first input image optical writing type spatial light modulator 11 through the first coordinate conversion optical filter 4 arranged immediately before the first input image optical writing type spatial light modulator 11. An image is formed on the writing surface and displayed as a correlated image on the first optical writing type spatial light modulator for input image 11. Similarly, the reference object 2
The first input image 1 passes through the second coordinate conversion optical filter 24 arranged immediately before the second input image optical writing type spatial light modulator 31 by the second image forming lens 30. An image is formed on the writing surface of the optical writing-type spatial light modulator for use 31 and displayed as a reference image on the second optical writing-type spatial light modulator for input image 31. As a result, each reference image and the correlated image are
The optical writing type spatial light modulators 11 and 3 for the first and second input images are formed as images superimposed on the coordinate conversion optical filter.
1 is displayed above. As described above, when the correlated image or the reference image is displayed on the first or second optical writing type spatial light modulators for input images 11 and 31, the coordinate conversion optical filter is also displayed together. It goes without saying that the coordinate conversion optical filter may be transmitted when the correlated image or the reference image is read out as in the above embodiment.

The coherent light emitted from the first coordinate conversion laser 5 and the second coordinate conversion laser 25 is
The light beam is expanded by the first coordinate conversion beam expander 6 and the second coordinate conversion beam expander 26, and is expanded by the first coordinate conversion polarization beam splitter 12 and the second coordinate conversion polarization beam splitter 32. After being reflected, the reading surface of each of the first and second optical writing type spatial light modulators for input images 11 and 31 is irradiated. As a result, the reference images and the correlated images displayed on the first and second optical writing type spatial light modulators for input images 11 and 31 are read out and converted into coherent images. Each coherent image is Fourier-transformed by the first coordinate conversion lens 7 and the second coordinate conversion lens 27, passes through the input image beam splitter 46, and is masked by a mask 48 to remove unnecessary DC bias components. As a result, only the coordinate conversion intensity distribution images are displayed on the first coordinate conversion optical writing type spatial light modulator 13 with a predetermined distance L therebetween. The processing after being displayed on the inter-optical modulator 13 is the same as that in the above-mentioned embodiment, and therefore, illustration and description thereof will be omitted.

FIG. 12 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. This shows a method in which the reference image and the correlated image are displayed on different electric writing type spatial light modulators, and then the coordinates are converted separately to electrically combine the coordinate conversion intensity distribution images. . Parts in FIG. 7 that have the same functions as those of the embodiment are designated by the same reference numerals, and the description thereof is omitted or simplified. Further, after electrically combining the coordinate conversion intensity distribution images, the description is omitted because it is the same as the embodiment described in FIG. Regarding the optical coordinate conversion unit, the means for obtaining the two-dimensional reference image and the correlated image are the first input image capturing device 2 and the second input image capturing device 22, and at least one coherent The light source includes a first coordinate conversion laser 5, a first coordinate conversion beam expander 6, a second coordinate conversion laser 25, and a second coordinate conversion beam expander 26. The at least one input image spatial light modulator holding the correlated image is composed of the first input image electrically writing spatial light modulator 3 and the second input image electrically writing spatial light modulator. The at least one coordinate conversion optical filter that is the modulator 23 and is arranged so as to overlap the input image spatial light modulator is the first coordinate conversion optical filter 4.
And the second coordinate conversion optical filter 24, and at least one lens is the first coordinate conversion lens 7 and the second coordinate conversion lens 27. Further, for different portions in the joint transform correlator unit, each coordinate transform image of the reference image and the correlated image obtained in the optical coordinate transform unit is transformed into a coordinate transform intensity distribution image, and each coordinate transform intensity is converted. The means for displaying the distribution image on the coordinate conversion image spatial light modulator includes a first mask 8, a first coordinate conversion imaging device 9, a second mask 28, a second input image imaging device 29, and a second input image imaging device 29. The second image processing device 41 and the electric writing type spatial light modulator 14 for coordinate conversion.

The correlated object 1 and the reference object 21 are respectively photographed by the first image pickup device for input image 2 and the second image pickup device for input image 22, and are respectively taken as the correlated image and the reference image. Are displayed on the input image electrically-written spatial light modulator 3 and the second input image electrically-written spatial light modulator 23. The coherent light emitted from the first coordinate conversion laser 5 and the second coordinate conversion laser 25 is expanded by the first coordinate conversion beam expander 6 and the second coordinate conversion beam expander 26. After that, the first input image electrically writing type spatial light modulator 3 and the second input image electrically writing type spatial light modulator 23 are irradiated. As a result, the displayed correlated image and reference image are each converted into a coherent image. Then, each coherent image is a first or second input-image electrically-writing spatial light modulator 3 or 23.
The first coordinate conversion optical filter 4 arranged immediately after
After passing through the second coordinate conversion optical filter 24 and the second coordinate conversion lens 27 separately.
By performing the Fourier transform with, each coordinate conversion image is obtained on the conversion surface. Here, unnecessary DC bias components and the like are masked by the first mask 8 and the second mask 28 arranged immediately before the conversion surface so that only the necessary coordinate conversion image is transmitted. Then, the obtained coordinate-transformed image is received by each of the first coordinate-transformation imaging device 9 and the second coordinate-transformation imaging device 29 and converted into an electrical signal, and each electrical signal is subjected to the second image processing. It is input to the device 41 and synthesized. When this combined electrical signal is input to the coordinate-writing electrical writing type spatial light modulator 14, each coordinate-transformed intensity distribution image is displayed at a predetermined distance L, as in the arrangement shown in FIG. The subsequent processing is the same as that of the embodiment described with reference to FIG.

FIG. 13 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. Parts in FIG. 7 that have the same functions as those of the embodiment are designated by the same reference numerals, and the description thereof is omitted or simplified. Figure 7
The optical coordinate conversion unit is the same as the embodiment shown in. Regarding the configuration of the joint transform correlator unit, each coordinate transform image of the reference image and the correlated image obtained in the optical coordinate transform unit is transformed into a coordinate transform intensity distribution image, and each coordinate transform intensity distribution image is coordinated. The means for displaying on the converted image spatial light modulator comprises a mask 48, a first coordinate conversion image pickup device 9, an image switching device 52, an image memory device 43, and a coordinate conversion electrically writing type spatial light modulator 14. The means for converting each coordinate conversion intensity distribution image displayed on the coordinate conversion image spatial light modulator into a coherent image comprises a Fourier transform laser 101 and a Fourier transform beam expander 102. The means for obtaining the joint Fourier transform image of the coordinate transform intensity distribution image by performing Fourier transform using a lens is a first Fourier transform lens. 104, means for converting the joint Fourier transform image into a Fourier transform intensity distribution image and displaying the Fourier transform intensity distribution image on the Fourier transform image spatial light modulator are a Fourier transform imaging device 106 and an image switching device. Means 52 for reading out the Fourier transform intensity distribution image displayed on the Fourier transform image spatial light modulator by using coherent light. Is composed of a Fourier transform laser 101 and a Fourier transform beam expander 102, and a correlation output image obtained by Fourier transforming the read Fourier transform intensity distribution image again using a lens The means for converting into a correlation signal using the first Fourier transform lens 104 and Fourier Conversion imaging device 106
And an image switching device 52, and means for determining the two-dimensional correlation coefficients of the reference image and the correlated image by the signal processing of the correlation signal comprises an identification circuit 206.

The process until the first coordinate conversion imaging device 9 receives the coordinate conversion image is the same as that of the embodiment shown in FIG. In addition, the image switching device 52 in the present embodiment
Is for interrupting or switching the flow of electric signals of the input and output of the image switching device 52. The electric signal output from the first coordinate conversion imaging device 9 is input to the coordinate conversion electric writing type spatial light modulator 14 via the image switching device 52 and the image memory device 43, and each coordinate conversion intensity. The distribution image is displayed on the coordinate-writing electric writing type spatial light modulator 14 at a predetermined distance L. The coherent light emitted from the Fourier transform laser 101 is applied to the coordinate-writing electrical writing type spatial light modulator 14 after the luminous flux is expanded by the Fourier transform beam expander 102. As a result, each coordinate-transformed intensity distribution image is transformed into a coherent image, which is Fourier-transformed by the first Fourier transform lens 104 to obtain a joint Fourier transform image on the transform surface. Therefore, the joint Fourier transform image is received by the Fourier transform imaging device 106 and converted into an electric signal, and the electric signal is output to the image memory device 43 via the image switching device 52. At this time, the electric signal from the first coordinate conversion imaging device 9 is not output to the image memory device 43 side by the image switching device 52. Fourier transform imaging device 10
The signal output from 6 is input to the coordinate-writing electrical writing type spatial light modulator 14 while being stored in the image memory device 43, and the Fourier transform intensity distribution image of the joint Fourier transform image can be displayed. it can. The Fourier transform intensity distribution image is Fourier transformed in the same manner as the coordinate transform intensity distribution image. The resulting correlation output image is received by the Fourier transform imaging device 106 and converted into a correlation signal, and this time the image switching device 52 outputs it to the identification circuit 206, where the correlation peak intensity is measured and the correlation coefficient is calculated. Is output. As described above, according to this embodiment, there is an advantage that the number of optical systems is smaller than that of the embodiment shown in FIG.

FIG. 14 is a block diagram of another embodiment of the optical pattern recognition apparatus having the coordinate conversion function according to the present invention. The parts having the same functions as those of the embodiment in FIG. 12 are designated by the same reference numerals, and the description thereof will be omitted or simplified. The optical coordinate conversion unit is the same as the embodiment shown in FIG.
Regarding the configuration of the joint transform correlator unit, each coordinate transform image of the reference image and the correlated image obtained in the optical coordinate transform unit is transformed into a coordinate transform intensity distribution image, and each coordinate transform intensity distribution image is coordinated. The means for displaying on the converted image spatial light modulator includes a first mask 8, a first coordinate conversion optical writing type spatial light modulator 13, a second mask 28 and a second coordinate conversion optical writing. Means for converting the coordinate conversion intensity distribution images displayed on the coordinate conversion image spatial light modulator into a coherent image by means of a Fourier transform laser 101 and a Fourier transform beam expander. 102, a mirror 108, a first Fourier transform polarization beam splitter 103, a mirror 110, and a second Fourier transform polarization beam splitter 123. Fourier transform with a lens,
The means for obtaining the joint Fourier transform image of the coordinate transform intensity distribution image is composed of the beam splitter 109 and the first Fourier transform lens 104. The joint Fourier transform image is transformed into the Fourier transform intensity distribution image, and the Fourier transform intensity distribution is obtained. The means for displaying the image on the Fourier transform image spatial light modulator comprises the Fourier transform optical writing type spatial light modulator 105. The subsequent processing is the same as that of the other embodiments and will not be described.

The part up to the point where the coordinate conversion image of the correlated image and the reference image is obtained on the conversion surface is the same as in the embodiment shown in FIG. Each coordinate conversion image obtained on the conversion surface is masked with unnecessary DC bias components and the like by the first and second masks 8 and 28, and then the first and second coordinate conversion optical writing types. The writing surface of the spatial light modulators 13 and 33 is illuminated, and the respective coordinate conversion intensity distribution images are displayed on the first and second optical writing type spatial light modulators for coordinate conversion 13 and 33. The coherent light emitted from the Fourier transform laser 101 has its luminous flux expanded by the Fourier transform beam expander 102, and then passes through a mirror 108 to be split into two luminous fluxes by a first Fourier transform polarization beam splitter 103. . One of the light fluxes illuminates the read surface of the first spatial light modulator 13 for optical writing for coordinate conversion as the read light, and the other light flux is reflected by the mirror 110 and the second polarization beam splitter 123 for Fourier transform. After that, the reading surface of the second optical writing type spatial light modulator for coordinate conversion 33 is irradiated with the reading light.
As a result, each coordinate-transformed intensity distribution image is transformed into a coherent image, which passes through the first and second Fourier transform polarization beam splitters 103 and 123 and the beam splitter 109, and is then Fourier transformed by the first Fourier transform lens 104. By being transformed, a joint Fourier transform image is obtained on the transform surface. Therefore, by irradiating the writing surface of the Fourier transform optical writing type spatial light modulator 105 with this joint Fourier transform image, the Fourier transform intensity distribution image is converted into the Fourier transform optical writing type spatial light modulator 10.
It is displayed in 5. The following processing is the same as that of the other embodiments and will not be described.

If the sizes and types of the correlated images and reference images are different, accurate pattern recognition may not be possible due to variations in the light intensity of the coordinate conversion images. Therefore, by optimizing the light intensity of the coordinate conversion image, more accurate pattern recognition becomes possible. The example is shown in FIG.
5 shows. As an automatic light control unit, the means for measuring the light intensity of the coordinate conversion image, the joint Fourier transform image, or the correlation output image or the change in the light intensity is composed of a light intensity measuring beam splitter 45 and a light receiving element array 49. A means for changing the light intensity according to the light intensity or a change in the light intensity, or the spatial light modulator for the coordinate conversion image, the spatial light modulator for the Fourier transform image, the imaging device, or the light receiving element. The means for changing the light receiving sensitivity is a light intensity adjusting device 50 and a liquid crystal mask 51.
Consists of.

The method for obtaining the coordinate-transformed image and the subsequent processing are the same as those in the other embodiments, and therefore will be omitted. A part of the light quantity of each coordinate conversion image is divided by the light intensity measuring beam splitter 45, and the light receiving element array 49 is irradiated with the light. Each light receiving element on the light receiving element array 49 is arranged corresponding to each coordinate conversion image. From the output from each light receiving element, the light intensity of each coordinate-converted image or its change amount can be measured.
Therefore, this output is input to the light intensity adjusting device 50 so that the light intensities of the coordinate conversion images become equal or optimum for the light receiving sensitivity of the first coordinate-writing optical writing type spatial light modulator 13. , The liquid crystal mask 51 arranged immediately before or after the first electrically-writing spatial light modulator for input image 3 is operated. That is, by changing the transmittance of the portion on the liquid crystal mask 51 corresponding to each correlated image or reference image,
The light intensity of each coordinate conversion image is made equal. By the above method, the light intensities of the coordinate conversion images are equalized, and accurate pattern recognition is possible even if the size or type of the reference image or the correlated image changes. It goes without saying that the same effect can be achieved by using the first electric writing type spatial light modulator for input image 3 instead of the liquid crystal mask 51.

Needless to say, more accurate pattern recognition is possible by optimizing the light intensity of the joint Fourier transform image and the correlation output image. Although many lasers are used in the above embodiment, it goes without saying that the output from one laser may be split into many light beams by using a beam splitter.

It goes without saying that the laser may be any laser having good coherence such as a gas laser or a semiconductor laser. It goes without saying that the coordinate conversion optical filter may be an amplitude modulation type or a phase modulation type.

[0066]

As described above, according to the present invention, the optical coordinate conversion unit for converting the coordinates of the reference image and the correlated image is used as the preprocessing of the joint conversion correlator unit.
Accurate recognition is possible even when the size or orientation of the correlated object changes. Furthermore, when an optical writing type or electric writing type spatial light modulator using a ferroelectric liquid crystal is used, high speed operation of about 30 Hz to 2 kHz becomes possible, and when a feedback system is added, Correlation processing with multiple reference objects is now possible.
In addition, the type of coordinate conversion and the reference image can be changed easily and at high speed. From the above, very high speed and accurate pattern recognition becomes possible, and effects such as speeding up and cost reduction can be expected in the fields of recognition devices and inspection devices.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 2 is a schematic diagram showing an outline of an optical coordinate conversion method.

FIG. 3 is a configuration diagram of a conventional VanderLugt type correlator having a coordinate conversion function.

FIG. 4 is a diagram showing an example in which a reference image and a correlated image are separated by a distance L and displayed on a first input image electrically-writing spatial light modulator 3.

FIG. 5 is a cross-sectional view showing a structure of a liquid crystal light valve using a ferroelectric liquid crystal used in the present invention.

FIG. 6 is a diagram showing an example of a relationship between an optical writing type ferroelectric liquid crystal light valve used in the present invention and a reading laser output, wherein (a) is a first coordinate converting optical writing type. Spatial light modulator 1
3 is a drive voltage, and (b) is a Fourier transform laser 101.
FIG. 4C is a diagram showing the output of FIG. 4, FIG. 6C is a drive voltage of the Fourier transform optical writing type spatial light modulator 105, and FIG.

FIG. 7 is a configuration diagram of another embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 8 is a diagram showing an example in which a correlated image and a plurality of reference images are arranged.

FIG. 9 is a configuration diagram showing a configuration of an embodiment when a feedback system is added to the optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 10 is a configuration diagram of another embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 11 is a configuration diagram of another embodiment of the optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 12 is a configuration diagram of another embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 13 is a configuration diagram of another embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 14 is a configuration diagram of another embodiment of an optical pattern recognition device having a coordinate conversion function according to the present invention.

FIG. 15 is a configuration diagram of an embodiment in which an automatic light control unit for a coordinate conversion image is added to the optical pattern recognition device having the coordinate conversion function according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Correlated object 2 1st input image imaging device 3 1st input image electric writing type spatial light modulator 4 1st coordinate conversion optical filter 5 1st coordinate conversion laser 6 1st coordinate conversion Beam expander 7 First coordinate conversion lens 8 First mask 9 First coordinate conversion imaging device 10 First imaging lens 11 First input image optical writing type spatial light modulator 12 One coordinate conversion polarization beam splitter 13 First coordinate conversion optical writing type spatial light modulator 14 Coordinate conversion electric writing type spatial light modulator 21 Reference object 22 Second input image imaging device 23 Second Input image electric writing type spatial light modulator 24 second coordinate conversion optical filter 25 second coordinate conversion laser 26 second coordinate conversion beam expander 27 second coordinate conversion lens 28 second mask 29 Second coordinate conversion Image device 30 Second image forming lens 31 Second input image optical writing type spatial light modulator 32 Second coordinate converting polarization beam splitter 33 Second coordinate converting optical writing spatial light modulator 41 second image processing device 42 first image processing device 43 image memory device 44 coordinate conversion optical filter array 45 beam splitter for measuring light intensity 46 beam splitter for input image 47 coordinate conversion lens array 48 mask 49 light receiving element array 50 light Intensity adjusting device 51 Liquid crystal mask 52 Image switching device 101 Fourier transform laser 102 Fourier transform beam expander 103 First Fourier transform polarization beam splitter 104 First Fourier transform lens 105 Fourier transform optical writing type spatial light modulation Device 106 Fourier transform imaging device 107 Fourier transform battery Writable spatial light modulator 108 Mirror 109 Beam splitter 110 Mirror 123 Second Fourier transform polarization beam splitter 131a, 131b Transparent substrate 132a, 132b Transparent electrode layer 133a, 133b Alignment film layer 134 Ferroelectric liquid crystal layer 135 Photoconductivity Layer 136 Light-shielding layer 137 Dielectric mirror 138a, 138b Antireflection coating layer 139 Spacer 150 Erase pulse 151 Write pulse 152 Zero voltage 153 Laser irradiation 154 Erase pulse 155 Write pulse 156 Zero voltage 157 Laser irradiation 201 Correlation laser 202 Correlation Beam expander 203 Polarization beam splitter for correlation 204 Second Fourier transform lens 205 Light receiving element 206 Discrimination circuit 207 Feedback mask 208 Feedback control circuit 301 Laser 302 Beam Expander 303 LCD TV 304 Coordinate Conversion Optical Filter 305 Beam Splitter 306 Mirror 307 Coordinate Conversion Lens 308 Liquid Crystal Light Valve 309 Beam Splitter 310 Polarized Beam Splitter 311 Fourier Transform Lens 312 Photographic Plate 313 Shutter 314 Mirror 315 Fourier Transform Lens 316 Light receiving element

Claims (9)

[Claims] 1. An optical pattern recognition apparatus for automatically recognizing and measuring a required pattern by performing an optical correlation process using coherent light on a two-dimensional image obtained from a CCD camera or the like, An optical coordinate conversion unit for obtaining a coordinate conversion image obtained by converting at least one reference image including a desired target and at least one newly input correlated image into a desired coordinate system; and the optical coordinate conversion unit. The joint coordinate correlator unit obtains a correlation coefficient between the obtained coordinate-transformed image of the reference image and the coordinate-transformed image of the correlated image, and the optical coordinate transform unit includes the two-dimensional reference image and Means for obtaining the correlated image, at least one coherent light source, and at least one spatial light modulation for input image holding the reference image and the correlated image And at least one coordinate conversion optical filter arranged to overlap the input image spatial light modulator, and at least one lens, wherein the joint conversion correlator unit is obtained in the optical coordinate conversion unit. Means for converting each coordinate conversion image of the reference image or the correlated image into a coordinate conversion intensity distribution image and displaying the coordinate conversion intensity distribution image on the coordinate conversion image spatial light modulator; and the coordinate conversion image. Means for converting each of the coordinate conversion intensity distribution images displayed on the spatial light modulator for use into a coherent image, and Fourier transforming the coherent image using a lens,
Means for obtaining a joint Fourier transform image of the coordinate transform intensity distribution image, and means for converting the joint Fourier transform image into a Fourier transform intensity distribution image, and displaying the Fourier transform intensity distribution image on a Fourier transform image spatial light modulator. And means for reading the Fourier transform intensity distribution image displayed on the Fourier transform image spatial light modulator using coherent light, and Fourier transforming the read Fourier transform intensity distribution image again using a lens. Means for converting the correlation output image obtained by the above into a correlation signal using an image pickup device or a light receiving element, and signal processing the correlation signal to obtain two-dimensional correlation coefficients of the reference image and the correlated image. An optical pattern recognition device having a coordinate conversion function, which comprises: 2. An optical pattern recognition apparatus having a coordinate conversion function according to claim 1, wherein the normalization circuit normalizes the correlation coefficient with a maximum correlation coefficient, the input image spatial light modulator, or A mask spatial light modulator arranged immediately before or after the coordinate conversion image spatial light modulator, and a portion corresponding to each reference image or each coordinate conversion intensity distribution image on the mask spatial light modulator. A coordinate transformation, characterized by comprising a feedback section comprising means for changing the transmittance or reflectance in a linear or non-linear relationship based on the correlation coefficient normalized by the normalizing circuit. An optical pattern recognition device having a function. 3. An optical pattern recognition apparatus having a coordinate conversion function according to claim 2, wherein a portion corresponding to each of the reference images and the correlated images of the mask spatial light modulator or each of the coordinate conversion intensity distributions. The transmittance or reflectance of the portion corresponding to the image is changed according to the area ratio or the transmitted / reflected light intensity of the reference image and the correlated image or the coordinate conversion intensity distribution image, and the coordinate conversion is performed. An optical pattern recognition apparatus having a coordinate conversion function, comprising means for normalizing the intensity distribution image so that the Fourier transform images have the same intensity. 4. The non-linear relationship in the feedback unit according to claim 2, which is expressed by a saturated function, a step function of at least one step or a combination of a saturated function and a step function, and coordinates. An optical pattern recognition device having a conversion function. 5. The spatial light modulator for coordinate conversion images, wherein each coordinate conversion image of the reference image or the correlated image according to claim 1 is converted into a coordinate conversion intensity distribution image. Means for converting each of the coordinate conversion images into a binarized coordinate conversion intensity distribution image and displaying it on the coordinate conversion image spatial light modulator. Pattern recognition device. 6. The means for converting the joint Fourier transform image to a Fourier transform intensity distribution image according to claim 1, and displaying the Fourier transform intensity distribution image on a Fourier transform image spatial light modulator. An optical system having a coordinate conversion function, which is a means for converting a transformed image into a binarized Fourier transform intensity distribution image and displaying the binarized Fourier transform intensity distribution image on a Fourier transform image spatial light modulator. Pattern recognition device. 7. A means for converting each of the coordinate conversion images into a binarized coordinate conversion intensity distribution image and displaying it on the coordinate conversion image spatial light modulator according to claim 5, or the joint Fourier transform. Means for converting the image into a binarized Fourier transform intensity distribution image and displaying the binarized Fourier transform intensity distribution image on the Fourier transform image spatial light modulator has a bistable memory property between the light reflectance and the applied voltage. By means of irradiating the coordinate-transformed image or the joint Fourier-transformed image to the optical writing type spatial light modulator for coordinate-transformed image or the spatial light modulator for Fourier-transformed image using a ferroelectric liquid crystal having An optical pattern recognition device having a coordinate conversion function characterized by being present. 8. A means for converting each of the coordinate conversion images into a binarized coordinate conversion intensity distribution image and displaying it on the coordinate conversion image spatial light modulator according to claim 5, or the joint Fourier transform. Means for converting the image into a binarized Fourier transform intensity distribution image and displaying the binarized Fourier transform intensity distribution image on a spatial light modulator for Fourier transform image is an imaging device for the coordinate transform image or the joint Fourier transform image. Is converted into an image signal by receiving light using
After the binarization of the image signal, the optical signal having a coordinate conversion function is characterized in that the image signal is inputted to an electric writing type spatial light modulator for coordinate conversion image or a spatial light modulator for Fourier transform image for display. Pattern recognition device. 9. An optical pattern recognition device having a coordinate conversion function according to claim 1, wherein the optical intensity of the coordinate transformed image, the joint Fourier transformed image, or the correlation output image or a change in the light intensity is measured. And a means for changing the light intensity according to the light intensity or a change in the light intensity, or the spatial light modulator for coordinate conversion images, the spatial light modulator for Fourier transform images, the imaging device, or the light receiving element. An optical pattern recognition device having a coordinate conversion function, comprising: an automatic light control section including a means for changing the light receiving sensitivity of the.