JPH0795180B2 - Optical identification device - Google Patents

Description

The present invention relates to an optical identification device used in the field of optical information processing.

[Problems to be Solved by Related Art and Invention] Generally, as a method of obtaining a cross-correlation between a reference image group and a test image, a Fourier transform hologram of a reference image is conventionally used.
A first method of changing the direction of the reference light for each reference image to form a hologram, that is, a so-called multiple hologram is taken and used as a correlation filter, and a joint Fourier transform image of the reference image group and the test image A second method (refer to Japanese Patent Laid-Open Nos. 57-138616, 57-210316, and 58-21716) is proposed, in which the data is recorded in the form of an intensity distribution, then read with coherent light, and then Fourier-transformed again.

However, in the first method described above, a hologram storage element is required, but with a photographic plate which is a typical recording material thereof, it takes time to develop the plate and the direction of the reference light is changed in each reference image. It requires very complicated work to change each time, and it is impossible to perform real-time processing.

On the other hand, in the second method described above, these drawbacks are solved, but the joint Fourier transform image is a multiple interference fringe formed by each reference image and each reference image and the test image. In addition, if a congruent Fourier transform image with a reference image that is too much for the dynamic range and resolution of the spatial modulator is recorded, the visibility of the interference fringes will be extremely reduced, and in reality, recognition will be performed by comparing a number of test images. It is impossible to use for.

The present invention has been made to solve the above-mentioned problems, and performs a correlation calculation between a reference image group and a test image in real-time operation without using a means such as holography to form a feedback system. Thus, it is an object of the present invention to provide an optical identification device capable of dramatically increasing the number of reference image groups. A further object of the present invention is to provide an optical discriminating apparatus which can accurately recognize a test image by the above-mentioned arithmetic method.

Then, the present invention forms multiple interference fringes by the reference image group and the test image, reduces the information that the spatial filter does not need to identify, and a light intensity distribution according to the light intensity distribution of the multiple interference fringes or Form a coherent light flux with a phase distribution,
The light flux is subjected to Fourier transform, and the obtained two-dimensional light intensity distribution represents the position of the test image and each reference image and the degree of correlation thereof. Further, the two-dimensional light intensity distribution is input to the image output means and cross-correlated. The two-dimensional light intensity distribution can be obtained due to the high and low characteristics, and a reference image group that is close in shape to the test image is left, the visibility of the interference fringes obtained by the Fourier transform means is increased, and the remaining image is also accurate. It is an object of the present invention to provide an optical discriminating device that enables various comparisons.

[Means for Solving the Problems] In order to solve the above-mentioned technical problems, the present invention outputs at least a coherent image based on an image to be inspected and a reference image group at the same time, and electrically or optically. A first image output means (for example, 1) capable of temporally and spatially modulating the output light complex amplitude, and an optical two-dimensional distribution pattern of the output light complex amplitude from the first image output means. Fineness (dimension) of the first optical Fourier transform means (for example, 2) that performs the Fourier transform and the light receiving range of the output light from the first Fourier transform means to be compared (desired) with the test image. A spatial filter (for example, 3) that limits the spatial frequency range according to the above, and a coherent secondary according to the spatial light intensity distribution pattern of the light output from the first optical Fourier transform means that has passed through the spatial filter. Second image output means (for example, 4) capable of changing the original output light complex amplitude distribution, and optically Fourier transforming a two-dimensional distribution pattern of the output light complex amplitude from the second image output means. Then, the output thereof is input to the first image output unit (for example, 1) as the modulation signal, and the second optical Fourier transform unit (for example, 5) is inputted, and the light from the second optical Fourier transform unit is inputted. It is an optical discriminating device characterized in that it essentially comprises a light detecting means (for example, 6) for detecting an output.

[Operation] With the configuration of the optical discriminating apparatus of the present invention as described above, the spatial patterns of the reference image group and the test image presented by the first image output unit are the first optical Fourier transforming unit. Fourier transform is performed to form multiple interference fringes formed by the reference image group and the test image. At this time, since the light flux passes through the spatial filter, information such as fine defects (defects) that do not need to be identified disappears, and the second image output means responds to the light intensity distribution of the multiple interference fringes. A coherent light beam having a light intensity distribution or a phase distribution is emitted.

The coherent light beam is optically Fourier-transformed by the second optical Fourier transforming means, and as a result, the obtained two-dimensional light intensity distribution is the position of the test image and each reference image and its correlation degree. Will be represented. Here, the two-dimensional light intensity distribution is input to the first image output means, and the output light intensity of the first image output means corresponds to a large portion of the two-dimensional light intensity distribution. It is large in the image part and small in the opposite part.

While the above operation is repeated, the light intensity emitted from the reference image having a relatively low cross-correlation coefficient is sequentially reduced with respect to the test image, and the reference image group having a shape close to the test image is generated. The number of remaining reference images to be compared is reduced. As a result, the visibility of the interference fringes obtained by the first Fourier transform means rises, and accurate comparisons can be made for the remaining images. And further,
By repeating this process, only the one having the highest cross-correlation coefficient remains, which is recognized as the test image.

The optical discriminating apparatus of the present invention outputs at least a coherent image of a test image and a reference image group at the same time, and can electrically or optically modulate the output optical complex amplitude in time and space. An image output unit (for example, 1); a first optical Fourier transform unit (for example, 2) for optically Fourier transforming a two-dimensional distribution pattern of the output light complex amplitude from the first image output unit; A spatial filter (for example, 3) that limits the light receiving range of the output light from the first Fourier transforming unit to a spatial frequency range corresponding to the fineness of details to be compared in the test image, and the spatial filter that passes through the spatial filter. Second image output means capable of changing the coherent two-dimensional output complex amplitude distribution according to the spatial light intensity distribution pattern of the light output from the first optical Fourier transform means (for example, ) And an optical Fourier transform of a two-dimensional distribution pattern of the output light complex amplitude from the second image output means, and the output thereof is input to the first image output means as a modulation signal thereof. 2 optical Fourier transforming means (for example 5) and light detecting means (for example 6) for detecting the light output from the second optical Fourier transforming means, and a test image and a reference image group It is intended to recognize the test image by obtaining the cross-correlation coefficient of.

At this time, by changing the output light intensity from each reference image in the first image output means in a positive feedback manner by the output of the second Fourier transform means according to the cross-correlation coefficient, The influence from the image with a low correlation coefficient is selectively eliminated, and high-speed and accurate identification can be performed from a large number of reference images.

Then, in the optical discriminating apparatus of the present invention, the first image output means (for example, 1) modulates at least a coherent light source (for example, laser 11) with a pattern of spatial distribution of complex amplitude of the light flux from the light source. A possible first spatial light modulator (for example, a liquid crystal light valve 15) and one or a plurality of reference image groups and a test image to which the luminous flux emitted from the first spatial light modulator is input. There is a display body (for example, the image display device 16).

Also, a first spatial light modulator (eg, a liquid crystal light valve)
15) corresponds to each reference image that constitutes the reference image group,
The division is performed, and each section has its transmittance or reflection depending on the quantity of light of the output light (for example, the light intensity pattern on the screen 52) from the second optical Fourier transforming means. The rate changes.

At this time, the output from the second optical Fourier transform means (for example, the Fourier transform lens 51) is directly output to the first spatial light modulator if the first spatial light modulator is an optical input type. If it is an electric input type, it is received by the first two-dimensional photoelectric conversion element (for example, the two-dimensional photoelectric conversion element 61), and is image-processed and liquid crystal drive circuit 62 as an electric signal.
Then, the first spatial light modulator (for example, the liquid crystal light valve 15) is modulated.

A display body (for example, a part of the image display device 16) displaying the reference image group is, for example, a liquid crystal light valve 16a capable of being electrically modulated. And at the same time,
The display body (for example, another part of 16 ') for displaying the test image is an incoherent / coherent conversion element 16b.
Is preferred. Further, the first image output means (for example, 1) includes at least a coherent light source,
Third spatial light modulator capable of modulation by electric input for displaying the reference image group and the test image (for example, image display device 16)
However, it is preferable that it also has the function of the liquid crystal light valve 15 by itself. Then, the second image output means (for example, 4) includes at least a coherent light source,
Based on the signal (for example, from 42 to 45) from the second two-dimensional photoelectric conversion means (for example, 42) that receives the output light from the first Fourier transform means (for example, 21), It can consist essentially of a fourth spatial light modulator (eg 45) that modulates and outputs a complex amplitude distribution. The second image output means (for example, 4) has a two-dimensional optical characteristic depending on at least the coherent light source and the intensity distribution of the incident output light from the first Fourier transform means. Alternatively, it can consist essentially of a fifth three-dimensionally varying air conditioning light modulator (eg 45 ').

Next, the optical discriminating device of the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Embodiment] FIG. 1 is a schematic configuration diagram showing a configuration of an example of an optical identification device according to the present invention.

In the optical layout of FIG. 1, the optical discriminating device is composed of an image output means 1, an optical Fourier transform means 2, a spatial filter 3, an image output means 4, an optical Fourier transform means 5, and a light detection means 6. The configuration will be described in detail below.

A light beam 12 emitted from a coherent light source 11 such as a semiconductor laser or a gas laser is converted into an appropriate light beam diameter by a beam expander 13 and split into two optical paths by a beam splitter 14.

The light flux 12 that has passed through the beam splitter 14 passes through a liquid crystal light valve (hereinafter referred to as LCLV) 15 and the image display device.
Incident on 16. Here, the LCLV15 is a spatial light modulator that can spatially modulate the transmittance distribution by inputting an electrical signal, and the most common example is a liquid crystal panel used for a liquid crystal television or a computer display. Is used. The LCLV15 is initially set to have a uniform transmittance, but as a result of the subsequent steps, the shape has a high transmittance at the portion corresponding to the reference image, which has a high correlation with the test image. The transmittance of the non-exposed area becomes low.

As shown in FIG. 2, the image display device 16 is divided into a test image display portion 16b and a reference image display portion 16a, and the reference image display portion 16a records a plurality of reference images on a photographic film. Is a spatial light modulator capable of displaying a plurality of reference images or a plurality of reference images by electrical input or optical input, and the test image display portion 16b is a space where electrical or optical input of the test image is possible. It is an optical modulator. That is, as shown in the figure, the reference image group, for example, a, b,
c, d, and e are displayed in the 16a portion, and the test image s is displayed in the 16b portion.

Now, the light flux 12 that has passed through the image display device 16 passes through the Fourier transform lens 21 and enters the screen 41 placed on the Fourier transform surface thereof. On this screen 41, the light intensity proportional to the square of the two-dimensional Fourier transform of the complex amplitude distribution in the image display device 16 is observed. This light intensity distribution is detected by a two-dimensional photoelectric conversion element 42 such as a CCD. At that time, by limiting the visual field of the spatial filter 3 or the two-dimensional photoelectric conversion element 42, unnecessary fine defects on the image are detected. Information such as (defect) is cut.

Here, the image obtained by the two-dimensional photoelectric conversion element 42 passes through the video amplifier and the liquid crystal drive circuit 43 as an electric signal,
Displayed on the LCLV45. Like the LCLV15, this LCLV45 also forms a spatial light modulator, which modulates the complex amplitude of incident light and emits it. The light flux 47 incident on the LCLV 45 is the light flux 12 emitted from the laser 11 divided by the beam splitter 14, and therefore, the light source of the image output means 1 and the image output means 4 are used.
The source of light will be shared here.

The light flux 47 emitted from the LCLV 45 passes through the Fourier transform lens 51 and enters the screen 52. At this time, screen 52
Is the position of the Fourier transform with respect to LCLV45. Therefore, the light intensity on the screen 52 represents the degree of spatial cross-correlation and spatial autocorrelation between the reference image group and the test image. Becomes Therefore, if the images are arranged on the image display device so that they do not overlap the cross-correlation positions of the reference images, the two-dimensional photoelectric conversion element 61 of the CCD is displayed.
This makes it possible to detect the position of the reference image having a high correlation with the test image and the degree of the correlation.

Now, what the peak of the light intensity according to the degree of such cross-correlation is like will be described below by taking the pattern shown in FIG. 2 as an example.

On the image display device 16, as shown in FIG.
Reference image groups a, b, c, d, e and a test image s are drawn. If the spatial coordinates indicating the position of the image s to be inspected are (0,
0) and let this be denoted as s (0,0).

Similarly, the reference image groups are a (a _x , a _y ), b (b _x , b _y ),
Denote by c (c _x , c _y ), d (d _x , d _y ), e (e _x , e _y ). Irradiating these patterns with coherent light and performing Fourier transform with the Fourier transform lens 21,
The light intensity pattern I (f _x , f _y ) on 41 is as follows.

I (f _x , f _y ) = | S + A · exp (j2πf _x a _x ) exp (j2πf
_y a _y ) ＋ B ・ exp (j2πf _x b _x ) exp (j2πf _y b _y ) ＋ C ・ exp
(J2πf _x c _x ) exp (j2πf _y c _y ) ＋ D ・ exp (j2πf _x d _x ) ex
p (j2πf _y d _y ) ＋ E ・ exp (j2πf _x e _x ) exp (j2πf _y e _y )
｜ ² ＝ | S | ² ＋ | A | ² ＋ | B | ² ＋ | C | ² | D | ² ＋ | E | ² ＋ S ^*・ A ・
exp (j2πf _x a _x ) exp (j2πf _y a _y ) ＋ S ^*・ B ・ exp (j2
_{πf x b x) exp (j2πf} y b y) + S * · C · exp (j2πf x c x)
exp (j2πf _y c _y ) ＋ S ^*・ D ・ exp (j2πf _x d _x ) exp (j2
πf _y d _y ) + S ^*・ E ・ exp (j2πf _x e _x ) exp (j2πf _y e _y )
＋ c.c. ＋ A ^* B ・ exp (j2πf _x (b _x −a _x )) exp (j2πf _y (b
_y −a _y )) + A ^* C · exp (j2πf _x (c _x −a _x )) exp (j2πf _y
(C _y −a _y )) + …… D ^* E ・ exp (j2πf _x (e _x −d _x )) exp
(J2πf _y (e _y −d _y )) + c.c .... (1) where f _x and f _y are the spatial frequencies in the x and y directions on the screen 41, S, A and B, respectively. , C, D, E are the complex amplitudes of the Fourier transform of the light amplitude distributions of the test image and the reference image, and the ^* marks are the complex conjugate amounts of the light amplitude distributions of the respective images.

When the above light intensity pattern I (f _x , f _y ) is written in the LCLV45 as a transmittance distribution and Fourier transformed again by the Fourier transform optical system, the light intensity pattern I on the screen 52 is written.
(X, y) is I (x, y) = ∫I (f _x , f _y ) ・ exp (−j2πf _x x) exp (−j2πf _y y) df
_x · df _y = s * s + a * a + b * b + c * c + d * d + e
* E + s * a {δ (a x -x) δ (a y -y) + (a x + x)
δ ( _ay− y)} + s * b {δ (bx− _x ) δ (by− _y ) +
_{(B x + x) δ (} b y -y)} + s * c {δ (c x -x) δ
(C _y −y) + (c _x + x) δ (c _y −y)} + s * d {δ
_{(D x -x) δ (d} y -y) + (d x + x) δ (d y -y)} +
s * e {δ (e _x −x) δ (e _y −y) + (e _x + x) δ (e _y
-Y)} a * b {δ (b x -a x -x) δ (b y -a y -y) +
_{δ (b x -a x -x)} (b y -a y -y)} + ...... d * e {δ
(E _x −d _x −x) δ (e _y −d _y −y) + δ (e _x −d _x −x)
(E _y −d _y −y)} (2)

Here, * represents the correlation.

In this way, the autocorrelation of each image appears on the optical axis, and the cross-correlation between the test image and the reference image group is relative to the optical axis.
Each pair appears symmetrically at a position from the optical axis corresponding to the relative position between the test image and the reference image group. Further, the cross-correlation between the reference images also appears in the same manner, but if the reference image group and the test image are separated in advance, the cross-correlation between the test image and the reference image group and the cross-correlation between the reference images become There is no overlap. Therefore, the peak of the degree of cross-correlation between the test image and the reference image group appears at the position on the screen 52 corresponding to the position of the reference image group on the image display device 16.

However, in this state, if the number of reference images is large, it is impossible to clearly read the correlation peak of the reference image group with respect to the test image.

The reason is that the correlation term shown in the equation (2) is related to the formation of interference fringes due to the overlapping of the Fourier transform patterns of the images in the equation (1). When the visibility of the interference fringes decreases, the light intensity of the correlation peak decreases as a result, and when the fineness of the light intensity distribution of the formed interference fringes and the dynamic range exceed the capability of the spatial light modulator. , The output of the correct correlation peak cannot be obtained.

Therefore, in this embodiment, the light intensity on the screen 52 is read by the two-dimensional photoelectric conversion element 61, sent to the image processing and liquid crystal drive circuit 62 as an electric signal, and the cross-correlation amount with each reference image is standardized. By determining the transmittance distribution of LCLV15 according to the amount, the amount of light with which each reference image is irradiated is changed. That is, for example, if the reference image having the highest degree of correlation with the test image is b, the transmittance of the pixel portion of the LCLV 15 through which the light flux illuminating b is transmitted is maximized. In other reference images, for example, the reference image a
In contrast, the transmittance of the image portion through which the light flux illuminating the reference image a of the LCLV15 is transmitted is determined so that the light intensity illuminating a is equal to the light intensity s * a / s * b. . Hereinafter, the same applies to other reference images.

In this way, when the pattern after changing the transmittance of the LCLV15 and changing the amount of light applied to each reference image is input and the above operation is repeated, the reference image with a small correlation peak output is once The amount of irradiation light decreases, and as a result, it is possible to clearly recognize that the image to be inspected is b. Light detection means 6 based on the light intensity on the screen 52
Fig. 3 shows the relationship between the output and the number of trials.

That is, when the number of trials is plotted on the horizontal axis and the output of the light detection means 6 is plotted on the vertical axis, the output from the reference image b is constant but the output from other images decreases as the number of trials increases.

If there are some reference images with a high degree of correlation with the image to be inspected, a threshold level is set for the degree of correlation for some of the reference images with a low degree of correlation, and spatial modulation is performed at a stage where the number of trials is small. The transmittance of the vessel may be minimized. At this time, the reference image whose phase sensitivity becomes lower than the threshold after several trials can also lead to a quick result if the transmittance of the spatial light modulator is also set to the minimum.

Furthermore, since the number of reference images is limited at the initial stage, the number of objects to be compared is reduced in the subsequent operations (operations), the visibility of interference fringes is increased, and correct recognition is performed. If the same image as the test image was not present in the reference image, even if the number of trials was increased, the test image calmed down to a state in which there was no reference image having a significantly higher correlation than the others. It is also possible to ambiguously determine the degree of correlation with respect to the reference image.

Also in the above-mentioned embodiment, if the rule is set so that the transmittance to be changed is high for the reference image having substantially the highest degree of correlation and low for the other reference images, what kind of Needless to say, it may be a thing. For example, when the reference image having the highest degree of correlation is b, the light intensity irradiating another reference image a is defined as f (s * a) / f (s * b) with respect to the monotonically increasing function f (x). Is also possible.

Next, FIG. 4 is a schematic view showing the configuration of another optical discriminating apparatus of the present invention. The invention will now be further described.

In the optical discriminating apparatus shown in FIG. 4, the light beam 12 emitted from the laser 11 passes through the beam expander 13 and enters the polarization beam splitter 14 '. In the polarization beam splitter 14 ', only the s-polarized component is reflected, and the p-polarized component is transmitted to become a light beam 47.

Then, the light flux 12 composed of the s-polarized component enters the LCLV 15 '. Here, LCLV15 'is a reflection type liquid crystal light valve as shown in FIG. In this liquid crystal light valve, a photoconductive layer 77 and a dielectric mirror 75 are arranged between a liquid crystal panel sandwiched by transparent electrodes 72 and 78, and the photoconductive layer 77 is divided into required pixel sizes. Has been done. In this LCLV 15 ′, the size of this pixel is the size of the reference image in the image display device 16.

Here, the dielectric mirror 75 is arranged on the liquid crystal layer side (right side in the figure) with respect to the photoconductive layer 77, and this is the incident direction of the reading light. At this time, the transparent electrodes on both sides (ie 72 and 78)
When a writing light A is applied while a voltage is applied between the two), a voltage drop occurs in the photoconductive layer 77 in each divided pixel 70a in accordance with the amount of the writing light A, and the liquid crystal in each portion is affected. Readout light B that has been incident due to a change in voltage
Has its plane of polarization rotated. Therefore, the luminous flux 12 is LCLV1.
The polarization plane is rotated according to the writing light A incident on the 5 ', and the reflected light is transmitted through the polarization beam splitter 14' according to the intensity distribution of the writing light A. However, at the beginning of the process, a uniform light amount is transmitted through the polarization beam splitter 14 'for the entire luminous flux range by setting the bias potential or entering the bias light. The structure of the reflection type liquid crystal light valve of 15 is as shown in FIG. That is, the glass substrate 71, the transparent electrode 72, and the liquid crystal 7 are sequentially arranged.
4. The dielectric mirror 75, the photoconductive layer 77, the transparent electrode 78, and the glass substrate 76 are laminated, and are divided into 70a divided pixels.

Now, the light flux 12 that has passed through the polarization beam splitter 14 'is
The light enters the image display device 16, further passes through the mirror 22, the Fourier transform lens 21, and irradiates the LCLV 45 ′ with the intensity pattern by the Fourier transform of the complex amplitude on the image display device 16. The LCLV 45 'is basically the same as the LCLV 15', except that the above-mentioned light flux 12 is used as the writing light A and the size of the divided pixels is reduced according to the pattern of the interference fringes incident thereon. The readout light B for this LCLV 45 'is the light beam 47 that has passed through the polarization beam splitter 14'. This light beam 47 passes through the half-wave plate 46 and changes its polarization direction.
It rotates 90 degrees and enters the polarization beam splitter 48. At this time, since the polarization state of the light beam 47 is s-polarized with respect to the polarization beam splitter 48, almost all of the light beam 47 is reflected and enters the LCLV 45 ′, and becomes its read light. The luminous flux 47 incident on the LCLV 45 ′ is similarly modulated with the luminous flux 12 on the LCLV 15 ′, and the Fourier transform lens 51 forms a pattern corresponding to the Fourier transform of the intensity distribution of the luminous flux 12 incident on the LCLV 45 ′ on the screen 52 and It is incident on LCLV15 '. However, the light beam 47 incident on the LCLV 15 'is set so that its optical axis, that is, the 0th-order light spot position is located by the half mirror 54 at the position 55 of the test image on the LCLV 15'. At this time, the position of the reference image and the arrangement of the optical system are set in advance so that the light spot of the cross-correlation peak corresponding to each of them comes to the position of the reference image on the LCLV 15 ′.

Therefore, thereafter, with respect to the test image, the reference image having a strong correlation intensity is illuminated with the light flux having a stronger intensity, and the reference image having a weaker correlation intensity is illuminated with the light flux having a weaker intensity. The cross-correlation intensity output is obtained by detecting the light intensity distribution on the screen 52 with a two-dimensional photoelectric conversion element 61 such as a CCD.

In the present invention, although there are differences in specifications with respect to the portion functioning as the spatial light modulator, in principle, the same electrical address type and optical address type can be used. is there. As an example of the electric address type, in addition to the above-mentioned liquid crystal panel, a ceramic or crystal exhibiting an electro-optical effect such as PLZT, KDP, BSO (Bi ₁₂ SiO ₂₀ ) or the like to which a matrix electrode is added is often used. .

Also in the photo-addressable type, a material similar to that of the electric-addressed type is generally combined with a photoconductive layer as described in FIG. However, in a crystal having a photovoltaic effect such as BSO or BaTiO _3, there is no need to add a photoconductive layer because the photoinduced refractive index change occurs due to spontaneous polarization depending on the incident light intensity. It should be noted that these spatial modulators can be configured as a transmissive type or a reflective type. However,
In the case of an optical address type in which the reading light completely erases the information of the writing light, the wavelength range of the reading light and the writing light is separated so that the reading light does not affect the writing information. Ingenuity is needed.

Further, when the electric address type is used, a two-dimensional photoelectric conversion element and its drive circuit for obtaining the input image are required, but there is an advantage that the signal can be easily processed.

Incidentally, the commonly used incoherent-coherent conversion element belongs to the reflective spatial light modulator of the above-mentioned optical address, and in order to use it for the image display portion 16b of the image display device 16, the An imaging optical system for irradiating the incoherent-coherent conversion element with an input image is required. In the case of the parent, if the reference image display portion 16a is also a reflection type regardless of the optical address and the electrical address, it is easy to configure an optical system. A configuration diagram of an example of such an optical system is shown in FIG.

In the optical identification device shown in FIG. 6, the luminous flux from the laser 11
The image display device 1 is reflected by the beam splitter 14.
It is incident on 6 '. Here, the image display device 16 'is composed of an incoherent-coherent conversion element corresponding to the image display portion to be inspected and a reflective electrical address type spatial light modulator such as LCLV corresponding to the reference image display portion. The incoherent-coherent conversion element receives an optical modulation input from the side opposite to the light beam 12. This modulation input is, for example, as shown in FIG.
The image is formed by 16b on the screen of the incoherent / coherent element. Further, the input of the reference image display portion, the reference image group, the feedback information based on the cross-correlation degree detected by the two-dimensional photoelectric conversion element 61, that is, should be emitted from the image display device 16 'of each reference image. , Light intensity information is superimposed. That is, in the optical discriminating apparatus of FIG. 6, the image display device 16 'simultaneously functions as the LCLV 15 and the image display device 16 of the optical discriminating device of FIG. Here, the reference image memory 80 is further used.

Regarding the other parts, there is a difference in the combination of whether the spatial light modulator used is an electrical address type or an optical address type, or a transmissive type or a reflective type. And the description of the optical discriminating apparatus in FIG. 4 is almost the same, and the explanation numbers are represented by the corresponding ones.

As can be seen from the above description, these spatial light modulators can be in any combination, and therefore the optical identification device of the present invention can take a number of embodiments depending on the combination. You will be able to

[Advantages of the Invention] With the engineering discriminating apparatus according to the present invention, the following remarkable technical effects were obtained.

First, the number of reference image groups can be dramatically increased by performing a correlation operation between the reference image group and the test image in real time without using a means such as holography and using a feedback system. An optical discriminator capable of being provided can be provided.

Secondly, at the same time, an optical discriminating device capable of discriminating a test image accurately is provided.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of an example of the optical identification device of the present invention. FIG. 2 is a schematic diagram showing an image display device in an example of the optical identification device of the present invention. FIG. 3 is a graph showing the relationship between the number of trials and the output from the light detection means 6 in one example of the optical identification device of the present invention. FIG. 4 is a schematic configuration diagram showing the configuration of another example of the optical identification device of the present invention. FIG. 5 is a schematic configuration diagram illustrating the configuration of a reflective liquid crystal light valve used in the optical identification device of the present invention. FIG. 6 is a schematic configuration diagram showing the configuration of another example of the optical identification device of the present invention. [Description of Signs of Main Parts] 1, 4 ... Image output means 2, 5 ... Optical Fourier transform means 3 ... Spatial filter 5 ... Optical Fourier transform means 6 ... Photodetection means 11 ... Laser 12 , 47 ...... Luminous flux 13 ...... Beam expander 14 ', 48 ...... Polarization beam splitter 15, 45 ...... Liquid crystal light valve 16 ...... Image display device 16a ...... Reference image display part 16b ...... Test image display part 17 …… Imaging lens 18 …… Object to be inspected 21, 51 …… Fourier transform lens 41, 52 …… Screen 42, 61 …… Two-dimensional photoelectric conversion element 43 …… Video amplifier and liquid crystal drive circuit 46 …… 1 wavelength plate 48, 50 ...... Polarizing beam splitter 22, 23, 44, 53 …… Mirror 54 …… Half mirror 55 …… 0-dimensional cut filter 62 …… Image processing and liquid crystal drive circuit 70 …… Reflective liquid crystal valve 70a …… Fractional pixel 71, 76 …… Glass substrate 72, 78 …… Transparent electrode 7 3 …… Spacer 74 …… Liquid crystal layer 75 …… Dielectric mirror 77 …… Photoconductive layer

Claims (9)

[Claims] 1. A first image output means for outputting at least a coherent image of a test image and a reference image group at the same time, and capable of electrically or optically modulating the output light complex amplitude in time and space. A first optical Fourier transform means for optically Fourier transforming a two-dimensional distribution pattern of complex amplitude of output light from the first image output means, and output light from the first Fourier transform means. A spatial filter for limiting the light receiving range to a spatial frequency range according to the fineness of details to be compared in the image to be inspected, and the spatial light of the optical output from the first optical Fourier transform means that has passed through the spatial filter. Second image output means capable of changing a coherent two-dimensional output light complex amplitude distribution according to an intensity distribution pattern, and two-dimensional output light complex amplitude from the second image output means From the second optical Fourier transforming means and the second optical Fourier transforming means for optically Fourier-transforming the physical distribution pattern and inputting its output to the first image output means as its modulation signal. An optical discriminating device essentially consisting of a light detecting means for detecting a light output. 2. The first image output means includes at least a coherent light source, a first spatial light modulator capable of modulating a spatial distribution pattern of complex amplitudes of a light beam from the light source, and the first spatial light modulator. 2. The optical identification device according to claim 1, wherein the optical identification device comprises a reference image group to which the light flux emitted from the spatial light modulator of 1 is input and one or a plurality of display bodies for displaying the test image. 3. The first spatial light modulator is divided into sections corresponding to each reference image forming a reference image group, and each section is an output light from the second optical Fourier transform means. 3. The optical identification device according to claim 2, wherein a portion corresponding to each of the light is received and the transmittance or the reflectance changes according to the amount of the light. 4. The output from the second optical Fourier transform means is received by the first two-dimensional photoelectric conversion element,
The optical discriminating device according to claim 2, wherein the first spatial light modulator is electrically modulated according to an output signal from the first two-dimensional photoelectric conversion element. 5. The optical discrimination according to claim 2 or 3, wherein the display body for displaying the reference image group is a second spatial light modulator capable of being electrically modulated. apparatus. 6. The optical discriminating device according to claim 2, wherein the display body for displaying the test image is an incoherent-coherent conversion element. 7. The first image output means comprises at least a coherent light source and a third spatial light modulator capable of being modulated by an electric input for displaying a reference image group and a test image. The optical identification device according to claim 1. 8. The second image output means at least,
Fourthly, a complex amplitude distribution of incident light flux is modulated and output based on a signal from a coherent light source and a second two-dimensional photoelectric conversion means that receives the output light from the first Fourier transformation means. The optical identification device according to any one of claims 1 to 7, wherein the optical identification device essentially consists of 9. The second image output means includes at least:
From a coherent light source and a fifth spatial light modulator whose optical characteristics change two-dimensionally or three-dimensionally depending on the intensity distribution of the incident light output from the first Fourier transforming means. Claim 1 characterized by being essentially
Item 7. An optical identification device described in any one of items 7 to 7.