JPH0230496B2 - - Google Patents

Description

[Detailed Description of the Invention] (Description of the Technical Field) The present invention is based on the negative OR (NOR) between two images.
This invention relates to a negative disjunction device for calculating .

(Background of the Invention) Logical operations on one image or between images are possible by using image processing technology using an electronic computer.

When you want to perform a logical operation, such as negation, on the information of a single image, you can divide the image information into pixels and perform a logical operation, such as negation, on each pixel. Logical operations can be performed.

Also, if you want to perform a logical operation between two images, for example to calculate a logical sum, you must similarly decompose each image into pixels and calculate the logical sum of the corresponding pixels to reconstruct the image. For example, it is possible to obtain the results of logical operations between images.

To perform such calculations, a television imaging device, a frame memory that stores image information pixel by pixel, a frame memory that stores calculation results pixel by pixel, and an arithmetic circuit for logical operations are usually required. Become.

Such a calculation process involves many serial processes, and as the number of pixels increases, a larger arithmetic processing device is required.

(Object of the Invention) An object of the present invention is to provide a NOR calculation device for calculating a NOR between images, which has a novel configuration that is completely different from the image processing technology described above.

(Structure of the Invention) In order to achieve the above object, the present invention provides a NOR operation device for calculating a NOR between images, which includes a photocathode, a first surface facing the photocathode, and a second surface facing the photocathode. an electro-optic crystal having a transparent electrode on its surface; a spatial light modulation tube comprising a mesh electrode provided between the photocathode and the electro-optic crystal plate; a laser light source device that irradiates with linearly polarized laser light from the second surface side of the crystal; a photocathode of the spatial light modulation tube;
a mesh electrode, a voltage generation circuit that supplies an operating voltage to the transparent electrode, and a first and second
a writing optical device that forms an image of an image on the photocathode of the spatial light modulation tube, an irradiation optical device that uniformly irradiates the photocathode of the spatial light modulation tube, and a first surface of the electro-optic crystal. a polarizer onto which the reflected light is incident; the voltage generating circuit applies a voltage that is an odd multiple of a half-wavelength voltage or close to it between the mesh electrode and the transparent electrode, and applies a writing voltage to the photocathode; the photocathode is uniformly irradiated by the irradiation optical device to form a uniform charge on the first surface of the electro-optic crystal; Applying a voltage equal to or close to an even multiple of a half-wavelength voltage between the transparent electrodes, and applying a writing voltage to the photocathode,
A charge image corresponding to the image is formed on the first surface of the electro-optic crystal by forming the first image on the photocathode by the optical device, and a charge image corresponding to the first image is formed on the first surface of the electro-optic crystal. With the image preserved,
The voltage generation circuit applies a voltage equal to or close to an even multiple of the half-wavelength voltage between the mesh electrode and the transparent electrode, and a writing voltage is applied to the photocathode, so that the optical device generates the second image. A second image is written by forming it on the photocathode, and the electro-optic crystal is irradiated with the laser light source device, and the light transmitted through the polarizer is exposed to the first image.
and the second image.

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

FIG. 1 is a block diagram showing the configuration of the basic part of a logical sum operation device for calculating a negative logical sum between images according to the present invention.

A photocathode 31 is formed on the inner surface of the entrance window of the vacuum vessel 34 of the spatial light modulation tube 3 .

A first surface 33a of an electro-optic crystal 33 made of a 55° cut crystal of LiNbO ₃ is opposed to the photocathode, and a transparent electrode 33b is formed on the second surface.

A mesh electrode 32 is arranged in front of the first surface 33 a of the electro-optic crystal 33 .

The photocathode 31, the mesh electrode 32, and the transparent electrode 33b on the second surface of the electro-optic crystal 33 are connected to operating voltages from connection terminals 31c, 32c, and 33c, respectively.

The image I is supported on an image arrangement table 22 and illuminated by an incoherent light source 1, and the image of the image I is formed on the photocathode 31 of the spatial light modulation tube 3 by a lens 2.

The operating voltage is supplied from the terminals 31c, 32c, and 33c, and the voltage of the photocathode 31 is set to a lower voltage (writing voltage) than the voltage of the mesh electrode 32 and the transparent electrode 33b on the second surface of the electro-optic crystal 33. Within the above voltage range, the mesh electrode 32, the electro-optic crystal 3
By applying a voltage between the transparent electrodes 33b on the second surface of the electro-optic crystal 33, a positive or negative charge image corresponding to the image of electrons emitted by the photocathode 31 is formed on the first surface of the electro-optic crystal 33. Here, the secondary electron emission characteristics of the electro-optic crystal 33 are as shown in FIG. 7, similar to many materials, where the emission ratio δ is smaller than 1 when the voltage E ₁ peculiar to the crystal (substance) is lower than E ₁ . and the crystal-specific voltage E ₂
It has a characteristic that the release ratio δ is larger than 1 between E and the release ratio δ is smaller than 1 when it is larger than the above E ₂ .

When the voltage of the mesh electrode 32 is set to approximately _E2 , the difference between the voltage of the photocathode 31 and the voltage of the transparent electrode 33b on the second surface of the electro-optic crystal 33 is shown in FIG.
When a voltage is applied to the transparent electrode 33b to be greater than E ₂ , electrons are attached to the first surface 33a of the electro-optic crystal 33 until the voltage becomes equal to the voltage of the mesh electrode 32 (δ <1) A negative charge image is formed. When the potential due to the negative charge becomes equal to the potential E ₂ of the mesh electrode 32, the charge will not change even if electrons fly in after that. The parts to which electrons do not come are in an uncharged state.

The difference between the voltage on the photocathode 31 and the voltage on the transparent electrode 33b on the second surface of the electro-optic crystal 33 is shown in FIG.
The transparent electrode 33b is located between E ₁ and E ₂ .
When a voltage is applied to the area, secondary electrons (δ>1) generated by electrons that reach the first surface 33a of the electro-optic crystal 33 are captured by the mesh electrode 32, resulting in A positive charge image is accumulated in .

The potential due to positive charges is the potential of the mesh electrode 32.
When it becomes equal to E ₂ , it reaches equilibrium, and even if electrons come in after that, the charge will not change.

The parts to which electrons do not come are kept uncharged.

If electrons are not incident, the charge on the surface of the electro-optic crystal 33 is preserved even if the voltage is changed.

The state of this electro-optic crystal 33 is read out by laser light from a laser light source device.

The laser light source device includes a laser oscillator 4, a polarizer 5, a lens 6, a pinhole 7, and a collimating lens 8.

The light from the laser oscillator 4 is polarized by the crystal x
It is converted into linearly polarized light in the direction of 45° from the axis (or y′ axis).

The light is then magnified by a lens 6 and excess diffracted light is removed by a pinhole 7.

The light transmitted through the pinhole 7 is converted into parallel light by a collimating lens 8, and is made incident on the crystal from the second surface of the electro-optic crystal through a half mirror 9. The electro-optic crystal (LiNbO ₃ ) is cut into a wafer shape as shown in FIG.

Due to the surface charge of the LiNbO ₃ electro-optic crystal 33, the electric field applied in the thickness direction of the crystal changes, and the refractive index of the crystal in the x direction and y' direction changes as shown in the following equation.

nx＝nx ₀ −rx・E……(1) ny′=ny′ ₀ −ry′・E……(2) Here, nx ₀ , ny′ ₀ : x direction when no charge exists, y′ Refractive index in the direction E: Electric field generated in the crystal due to the presence of charges rx, ry': Electro-optic constant x-direction component of light incident on the electro-optic crystal 33,
Since the velocities of the y' direction components are different (because the refractive index of the crystal is different in the x and y' directions), the x and y' direction components of the light reflected from the crystal surface are given the following equations. A phase difference occurs, and the light is generally output as elliptically polarized light.

Γ=(2π/λ)・(El)・2(ry'−rx) ...(3) Here, λ: Wavelength of light output from laser oscillator 4 l: Thickness of crystal 33 This output light is polarized. When the light beam passes through the element 10, only one polarization direction component is extracted, and a coherent optical image modulated by the input image I is obtained as an output. At this time, the output light intensity I ₀ is given by the following formula.

I ₀ = Asin ² Γ/2 = Asin ² (π/2)・(V/Vπ) ...(4) Here, V: Voltage equivalent to charge σVπ: Voltage equivalent to charge σπ (half-wave voltage ) Figure 2 shows the curve based on equation (4).

As shown in FIG. 2, the electric field within the electro-optic crystal 33 changes due to surface charges, thereby changing the intensity of the reflected light.

The following can be understood from Figure 2.

When the surface charge of the electro-optic crystal is 0, that is, when there is no incidence of photoelectrons (hereinafter referred to as state a),
The laser light that enters the electro-optic crystal 33 via the half mirror 9, is reflected by the first surface, is reflected by the half mirror 9, and passes through the polarizer 10 is zero.

When the surface charge is -σπ (hereinafter referred to as state b) and when the surface charge is σπ (hereinafter referred to as state c), the transmitted light is at a maximum.

When the surface charge is -σπ/2 (hereinafter referred to as d state)
and when the surface charge is σπ/2 (state e below)
Then, the transmitted light is 1/2 of the maximum light.

FIG. 3 is a block diagram showing an embodiment of a NOR operation device for calculating a NOR operation between images according to the present invention.

The configurations of the spatial light modulation tube 3 and the laser light source device are the same as those described with reference to FIG.

Electrodes at various parts of the spatial light modulation tube 3 are connected to a voltage generation circuit 11.

An output terminal a of the voltage generating circuit 11 generates an image writing voltage Va. Va is normally +3kV (write prohibited state), and when it is 0, it is a write state. The mesh electrode 32 is connected to the voltage Vb from the output terminal b of the voltage generation circuit 11, and the transparent electrode 33b on the second surface of the electro-optic crystal 33 is connected to the voltage Vc from the output terminal c of the voltage generation circuit 11. . These voltages are usually positive voltages, and when Vb-Vc<0, writing is performed on the first surface 33a of the electro-optic crystal 33 using negative charges, and when Vb-Vc>0, writing is performed using positive charges. .

In this example, the half-wave voltage Vπ mentioned above is
It is 1.0kV.

The image to be calculated is placed on the image arrangement table 22 and irradiated by the incoherent light source 1 through the half mirror 16, and the transmitted light image is transmitted through the half mirror 17 and the imaging lens 2 to the spatial light modulation tube 3. It is formed on the photocathode 31.

The light from the incoherent light source 1 is partially split by the half mirror 16, and the total reflection mirror 14
is reflected and directed toward the shutter 13.

When shutter 13 is open,
The light that has passed through is reflected by the total reflection mirror 15, reflected again by the half mirror 17, and then reflected by the lens 2.
The photocathode 31 of the spatial light modulation tube 3 is uniformly irradiated.

The opening and closing of the shutter 13 is controlled by a shutter drive circuit 12.

Image writing is performed with the shutter 13 closed.

Next, an example of calculating the negative logical sum between the image Ix shown in FIG. 4A and the image Iy shown in FIG. 4B will be described in detail.

〔Preprocessing〕

By the voltage generation circuit 11, the terminal 3 of the mesh electrode
2c is applied with Vb=2 kV, and Vc=3 kV is applied to the transparent electrode of the electro-optic crystal 33. A negative half-wavelength voltage -Vπ is applied at Vb-Vc=-1.0kV.

With the shutter drive circuit 12 opening the shutter 13, the voltage Va of the photocathode 31 is changed from +3 kV to 0.
to form a write state.

Since the photocathode 31 is uniformly irradiated, a uniform charge -σπ is formed on the first surface of the electro-optic crystal 33.
The shutter 13 is closed, the voltage Va of the photocathode 31 is changed from 0 to +3 kV, and writing of the uniform charge -σπ is completed.

[Writing of the first image Ix] Vb = 2 kV is applied to the terminal 32c of the mesh electrode, and Vc = 2 kV is applied to the transparent electrode of the electro-optic crystal 33.
Vb−Vc=0kV.

The image Ix is placed at the position of the image placement table 22 shown in FIG. The image Ix is illuminated by the incoherent light source 1, and an image of the white circle portion is formed on the photocathode of the spatial light modulation tube 3.

The voltage Va on the photocathode is changed from +3 kV to 0 to form a written state.

Electrons do not fly to the surface of the electro-optic crystal 33 corresponding to the background part (black part) of the first image Ix.

Therefore, the charge in that part does not change and the previously written -σπ is preserved.

The characteristics of that part correspond to the position b in FIG.

Electrons fly to the signal part (white circle part) of the first image Ix, and the generated secondary electrons are transferred to the mesh electrode 3.
2, the negative charges are reduced and as a result, the charges become 0. This state corresponds to the state shown in FIG. 2a.

The writing of the first image Ix is completed by changing the voltage Va of the photocathode from 0 to +3 kV.

[Writing of the second image Iy] The image Iy is placed at the position of the image placement table 22 in FIG. 3. Image Iy and image Ix have a white circle in the center in common, and the positions of the other white circles are shifted from each other.
With Vb = 2 kV applied to the terminal 32c of the mesh electrode and Vc = 2 kV applied to the transparent electrode of the electro-optic crystal 33 (same state as in writing the first image), a writing voltage Va = 0 is applied to the photocathode. 2nd image Iy
Electrons do not fly to the surface of the electro-optic crystal 33 corresponding to the background part (black part). Therefore, the crystal surface corresponding to the black part of the second image is in the state written by the first image Ix, and the charge is 0.
and maintain the state of −σπ.

In other words, the charge on the black background part of the first image is -
It has a charge of σπ, and the white circle part in the first image maintains a charge of 0.

The electric charge of the white circle part of the second image and the black part of the first image changes from -σπ to 0.

The white circle in the center of the first image is already in a state of zero charge, and this equilibrium state does not change even if a charge from the photocathode is transferred to the second image. The writing voltage Va is changed from 0 to +3 kV to finish writing the second image.

The charges written in the above manner are the voltage Va,
It is saved even if Vb is set to 0.

In the electro-optic crystal written in this way,
When the reading light from the laser oscillator 4 of the laser light source device is applied, the charge on the surface of the electro-optic crystal 33 -
In the σπ portion, an electric field is formed in the crystal by a half-wave voltage, so the polarization state of the reading light changes in response to the electric field.

As a result, the data is read out as shown in FIG. 4C.
In the embodiment described above, writing was performed by changing the write voltage Va while irradiating an image onto the photocathode. However, writing is performed by keeping Va in the write state and controlling the image onto the photocathode with an optical shutter. can be made to do so.

Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

As shown in FIG. 5, inserting a microchannel plate 35 into the spatial light modulation tube 3 is convenient when calculating the NOR of weak images.

As an example, a 55° cut crystal of LiNbO ₃ is used as the electro-optic crystal of the spatial light modulation tube, but single crystals such as KDP and BSO can be similarly used.

(Description of Effects) As explained above, the device according to the present invention can obtain a negative disjunction between images by writing an image on the surface of an electro-optic crystal using electric charges.

The device according to the invention can be widely used for comparison or matching between images.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the main part of a NOR operation device for calculating a NOR operation between images according to the present invention. FIG. 2 is a graph showing the characteristics of the electro-optic crystal of the spatial light modulation tube of the NOR operation device for calculating the NOR between images according to the present invention. FIG. 3 is a block diagram showing an embodiment of a NOR operation device for calculating a NOR operation between images according to the present invention. FIG. 4 is an explanatory diagram showing an image that is the object of a logical operation and the result of the logical operation. FIG. 5 is a sectional view showing another embodiment of the spatial light modulation tube.
FIG. 6 is a schematic diagram for explaining the direction of the crystal axis of an electro-optic crystal. FIG. 7 is a graph showing the relationship between secondary electron energy and secondary electron emission ratio. 1... Incoherent light source, 2... Lens, 3...
Spatial light modulation tube, 31... Photocathode, 32... Mesh electrode, 33... Electro-optic crystal, 35... Microchannel plate, 4... Laser oscillator, 5... Polarizer,
6... Lens, 7... Pinhole, 8... Collimating lens, 9... Half mirror, 10... Polarizer,
11...Voltage generation circuit, 12...Shutter drive circuit,
13...Shutter, 14,15...Reflector, 16,1
7...half mirror, 20...reproduction image surface, 22...image arrangement stand.

Claims (1)

[Claims] 1. A photocathode, an electro-optic crystal having a first surface facing the photocathode and a transparent electrode provided on a second surface, and a combination of the photocathode and the electro-optic crystal plate. a spatial light modulation tube comprising a mesh electrode provided between the spatial light modulation tubes; a laser light source device that irradiates the second surface of the electro-optic crystal with linearly polarized laser light from outside the spatial light modulation tube; a voltage generating circuit that supplies an operating voltage to the photocathode, the mesh electrode, and the transparent electrode of the spatial light modulation tube; a writing optical device for forming a photocathode, an irradiation optical device for uniformly irradiating the photocathode of the spatial light modulation tube, and a polarizer for receiving light reflected by the first surface of the electro-optic crystal; A voltage generating circuit applies a voltage that is an odd multiple of a half-wave voltage or a voltage close to it between the mesh electrode and the transparent electrode, and a writing voltage is applied to the photocathode, and the photocathode is uniformly illuminated by the irradiation optical device. A uniform charge is formed on the first surface of the electro-optic crystal by irradiating the electro-optic crystal in a uniform manner, and the voltage generating circuit causes the mesh electrode to
By applying a voltage equal to or close to an even multiple of a half-wavelength voltage between the transparent electrodes and applying a writing voltage to the photocathode, the first image is formed on the photocathode by the optical device. A charge image corresponding to the image is formed on the first surface of the electro-optic crystal, and while the charge image corresponding to the first image is stored, the voltage generation circuit generates the mesh electrode and the transparent electrode. a voltage that is an even multiple of a half-wavelength voltage or a voltage close to it is applied between them, and a writing voltage is applied to the photocathode to form the second image on the photocathode by the optical device. An image configured to write an image, irradiate the electro-optic crystal with the laser light source device, and obtain a NOR between the first image and the second image using light transmitted through the polarizer. A NOR operation device that calculates the NOR between. 2. A NOR calculation device for calculating a NOR between images as claimed in claim 1, wherein the electro-optic crystal is a 55° cut crystal of LiNbO ₃ . 3. The NOR operation device for calculating the NOR between images as claimed in claim 1, wherein the spatial light modulation tube has a microchannel plate disposed between the photocathode and the mesh electrode.