JP2533809B2 - Image processing device - Google Patents

Description

The present invention relates to an image processing device using a spatial light modulator.

[Prior Art] As a device for creating, editing, and copying full-color images,
Color copiers are known.

Color copiers are generally classified into analog type and digital type, and each has its own advantages and disadvantages.

An analog color copier exposes an optical image,
Since a color copy is created by development, it is difficult to add image processing such as color correction and gradation processing. On the other hand, in a digital color copier, an original image is converted into a digital signal by an image scanner, and a color copy is made by a printer in accordance with the digital signal. Image processing and the like can be easily performed.

Comparing the color copies that are made, analog color copiers have smooth rooms (resolution is
Although it is about 800 DPI), color masking (separation of black and chromatic colors) is not easy and color reproducibility is not very good.
Specifically, a black line drawing may be colored. On the other hand, a digital color copying machine is easy to color mask and has excellent color reproducibility, but it is difficult to achieve high definition.
When the resolution is increased and the number of read pixels is increased, the amount of data increases and a high-speed processor and a large-capacity memory are required, which is significantly disadvantageous in cost compared with the analog method.

From this point of view, the analog type color copier is advantageous when a large amount of copy processing is to be performed, and the digital type color copier is suitable for the production of design manuscripts where color reproducibility is important and simple printing. Be advantageous.

As described above, since the analog method and the digital method have advantages and disadvantages, respectively, the image type, the processing purpose,
It is used properly according to the purpose.

However, there is no device capable of executing a combination of excellent processing by the analog method and excellent processing by the digital method, and in order to create a high definition image quality with good color reproducibility, it is very expensive due to the digital method. It was necessary to use the device.

Furthermore, there is no device capable of mixing analog images and digital images in one screen.

Therefore, the applicant has already proposed an image processing apparatus that can handle an image in which an analog image and a digital image are mixed and fused and that has high resolution and excellent color reproducibility.

In this image processing device, an analog writing system for writing an original image in an analog manner on a spatial light modulating element using liquid crystal, and an image written on the spatial light modulating element by a two-dimensional scanning with a laser beam is digitalized. A digital reading system for reading the image data, a processing unit for performing image processing on the read image data, a digital writing system for digitally writing the image data subjected to the above-described processing to the spatial light modulator by two-dimensionally scanning a laser beam, and It is provided with an analog reading system for analogically reading an image written in the spatial light modulator.

[Problems to be Solved by the Invention] In the above-described image processing apparatus proposed by the present applicant, high-speed or high-quality reading and writing can be performed by changing the scanning density of the laser beam of the digital reading system and the digital writing system. It can be performed. For example, if the scanning density is made coarse, the image quality is deteriorated, but since the amount of information is reduced, the scanning time and the transmission time are shortened, and high-speed reading and writing can be performed. On the contrary, if the scanning density is made fine, it takes time, but high-quality reading and writing can be performed. Further, if the scanning density is made fine at the time of reading and the normal scanning density is made at the time of writing, an enlarged image can be obtained.

However, in the above-described image processing device, the limit of the scanning density is determined by the beam spot diameter of the laser beam, and if the beam spot diameter is relatively large, the pixel and the beam spot can correspond even if the scanning density is made fine. However, there was a limit to the improvement of image quality.

On the contrary, if the beam spot diameter is set small, it becomes difficult to accurately represent the image when the scanning density is made coarse. In particular, a large error occurs when reading a pattern having a spatial frequency close to the scanning density.

Therefore, an object of the present invention is to perform image processing capable of obtaining the best image quality at the scanning density of the laser beam in the digital reading system and the digital writing system, and outputting an image with less error. To provide a device.

[Means for Solving the Problems] A feature of the present invention that achieves the above object is that a photoconductor that constitutes an image writing plane, a liquid crystal layered on the photoconductor,
And a spatial light modulator having electrodes sandwiching a photoconductor and a liquid crystal, an analog writing system for analogly writing an original image in the spatial light modulator, and two-dimensionally scanning a laser beam on the spatial light modulator. A digital reading system that digitally reads the image written in the spatial light modulator, a processing unit that performs image processing on the read image data, and an image that has been subjected to the above-described processing by two-dimensionally scanning a laser beam. A digital writing system for digitally writing data in the spatial light modulation element, an analog reading system for reading out an image written in the spatial light modulation element in an analog manner, and means for variably controlling the scanning density of the laser beam to a desired value. And means for adjusting the beam spot diameter of the laser beam according to the controlled scanning density.

[Operation] First, the original image is written in the spatial light modulator in an analog manner, and the image thus written in the spatial light modulator is digitally read out for each pixel by the two-dimensionally scanned laser beam. . Then, the read image data is digitally rewritten in the spatial light modulator by the two-dimensionally scanned laser beam after the desired image processing. Finally, the image is read out from the spatial light modulator in an analog manner.

In the case of digital reading, digital writing, or both, when the scanning density of the laser beam is variably controlled to a desired value, the beam spot diameter of the laser beam is adjusted according to the controlled scanning density. Then, digital reading and digital writing are performed with a beam spot diameter optimal for the scanning density.

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

FIG. 2 is a block diagram schematically showing the basic structure of a color image editing / outputting device as an embodiment of the present invention.

In the figure, 10 is a spatial light modulation element having an image writing plane, 11 is an analog writing system of an image to the spatial light modulation element 10, 12 is an analog reading system, 13 is a digital reading system, and 14 is a digital writing system. Shows.

The digital read system 13 and the digital write system 14 are
It is electrically connected to a processing unit 15 that performs various image processing. A display 16 and a control unit 17 are connected to the processing unit 15.

The control unit 17 is mainly composed of a computer, and has the above-mentioned analog writing system 11 and analog reading system.
12, digital read system 13, and digital write system 14
Is electrically connected to In FIG. 2, white arrows represent an optical image by analog, black arrows represent an optical image by digital, and a broken line represents an electrical signal.

The spatial light modulation element 10 changes the transmittance distribution, the reflectance distribution, or the phase distribution according to the spatial intensity distribution (optical image) of the input light, so that the intensity distribution of the light, that is, the image Can be stored temporarily. When the spatial light modulation element storing the image is irradiated with other light, the transmitted light, the reflected light, the reflected light, or the like depending on the stored two-dimensional (spatial) image information.
Alternatively, the scattered light is modulated. By detecting or exposing the modulated transmitted light, reflected light, or scattered light, the written image is read.

The spatial intensity distribution of the light input to the spatial light modulator 10 may be an analog image which is an optical image, or a digital image which is obtained by two-dimensionally scanning a modulated laser beam. . Further, when reading from the spatial light modulation element 10, uniform light may be applied to the spatial light modulation element 10 to obtain an analog image, or a laser beam having a constant intensity may be two-dimensionally scanned and applied. It may be a digital image obtained by

The analog writing system 11 has a function of writing the optical image of the original image on the original document 18 into the spatial light modulation element 10.
It is mainly composed of a light source for illuminating the light source and an optical system for forming an optical image of an original image obtained by the light source on the spatial light modulator 10.

The analog reading system 12 has a function of projecting the optical image written in the spatial light modulation element 10 onto a recording paper 19 such as a photosensitive paper, and a light source for illuminating the spatial light modulation element 10 and a light source for illuminating the spatial light modulation element 10. Recording paper with the image of the spatial light modulator 10
It is mainly composed of an optical system for focusing on 19.

The digital reading system 13 has a function of reading the image written in the spatial light modulator 10 two-dimensionally with a laser beam and irradiating the image, thereby reading the image signal in time series. It is mainly composed of a scanning system and a light receiving system.

The digital writing system 14 has a function of writing a digital image in the spatial light modulation element 10 based on an image signal given from the processing unit 15, and is mainly composed of a laser light source, a laser beam scanning system, and a laser beam modulation unit. Has been done.

The processing unit 15 performs digital image processing on the image signal applied from the digital reading system 13 and outputs the processed image signal to the digital writing system 14. This processing unit 15
The result processed by is displayed on the display 16.

An image editing / outputting function can be obtained by combining all the above-mentioned configurations. Furthermore, an image editing function can be obtained by combining the spatial light modulator 10, the digital reading system 13, the processing unit 15, and the digital writing system 14. Also, the analog writing system 11, the spatial light modulator 10,
An image scanner function can be obtained by combining the digital reading system 13 and the digital reading system 13. Furthermore, the printer function can be obtained by combining the digital writing system 14, the spatial light modulator 10, and the analog reading system 12. Then, by combining the analog writing system 11, the spatial light modulator 10, and the analog reading system 12, an analog copying function can be obtained. Each of these functional modes is realized by the computer of the control unit 17.

FIG. 1 more specifically shows the configuration of the embodiment shown in FIG.

The analog writing system 11 shown in FIG. 2 has R (red),
Three light sources of G (green) and B (blue) (eg fluorescent lamp)
11a, 11b, 11c and the optical system represented by the lens 11d. The original document 18 is sequentially illuminated with uniform light from the light sources 11a, 11b, and 11c, so that the optical image of the original image is reduced and projected onto the writing plane of the spatial light modulator 10 by the lens 11d.

Color separation of a color image is performed in a frame sequential manner. For one original image, first, the R light source 11a is turned on, the optical image is written to the spatial light modulator 10, the image is read out, and then the G light source 11b is turned on to scan the optical image in space. After writing to the light modulation element 10 and reading the image, the same processing is performed on the B light source 11c.

In order to obtain a color separated image, there is a color filter system in addition to the above-mentioned light source switching system.

This color filter system is a system in which R, G, and B color filters are provided between the lens 11d and the spatial light modulator 10, and these are sequentially switched to obtain a color separation image. Specifically, the R, G, and B color filters are attached to, for example, a rotator and rotated to sequentially switch the color filters. In the color filter method, a white light source such as a halogen bulb is used as a light source.

In the light source switching method and the color filter method, three colors of cyan, yellow, and magenta may be used instead of the three colors of R, G, and B.

The digital readout system 13 has a laser light source 13a, a beam spot diameter adjusting unit 13b, a laser beam scanning system 13c, a condenser lens 13d, and a light receiving element 13e. Laser light source 13
A laser beam having a constant light intensity emitted from a is applied to the beam spot diameter adjusting unit 13b to adjust the spot diameter, and then applied to the laser beam scanning system 13c to be deflected in the vertical and horizontal directions. As a result, the laser beam two-dimensionally scans the spatial light modulator 10. The transmitted light, the reflected light, or the scattered light modulated according to the image information of the pixel corresponding to the laser beam spot is applied to the light receiving element 13e via the lens 13d and photoelectrically converted. In this way, the image information written on the spatial light modulator 10 can be read out in time series.

In order to obtain color image information, such a reading operation is performed for each color separated image of R, G and B. The read image information is sent to the processing unit 15.

As the laser light source 13a, a semiconductor laser or a sus laser such as He—Ne (helium-neon) is used. Since the semiconductor laser is small, the entire device can be made compact. Further, since the gas laser has good coherence, the spot diameter of the laser beam can be made small, which can further improve the reading resolution.

The light receiving element 13e can be composed of a high speed photodiode. If the laser beam has a slit shape extending in the sub-scanning direction in order to read image information for several lines (sub-scanning direction) at one time, a diode array or CCD is used as the light receiving element.
(Charge-coupled device) may be used.

The beam spot diameter adjusting unit 13b, which is one configuration example of means for adjusting the beam spot diameter of the laser beam of the present invention, and the laser, which is one configuration example of means for variably controlling the scanning density of the laser beam of the present invention to a desired value. The beam scanning system 13c will be described in detail later.

The digital writing system 14 includes a laser light source 14a, a beam spot diameter adjusting unit 14b having the same configuration as the beam spot diameter adjusting unit 13b, a laser beam scanning system 14c, and a laser modulation circuit.
14d and. A signal is applied from the processing unit 15 to the laser modulation circuit 14d, and the intensity of the laser beam generated from the laser light source 14a is modulated according to the signal. When a semiconductor laser is used as the laser light source 14a, it can be directly modulated by modulating its drive current, but when a gas laser is used, a modulator (not shown) for externally modulating the emitted laser beam is required. Is.

The modulated laser beam has a beam spot diameter adjustment unit.
The spot diameter is adjusted by being applied to 14b, and then applied to the laser beam scanning system 14c to be deflected vertically and horizontally. As a result, the laser beam scans the spatial light modulator 10 two-dimensionally. The laser beam spot on the spatial light modulator 10 corresponds to one pixel, and its light intensity represents the gradation of the pixel.

A beam spot diameter adjusting unit 14b, which is one configuration example of means for adjusting the beam spot diameter of the laser beam of the present invention, and a laser, which is one configuration example of means for variably controlling the scanning density of the laser beam of the present invention to a desired value. The beam scanning system 14c will be described in detail later.

The laser modulation circuit 14d and the laser beam scanning system 14c operate in synchronization with each other, and write a digital image in the spatial light modulation element 10 based on the signal given from the processing unit 15. In order to handle color image information, such a writing operation is performed for each color of R, G and B.

The analog reading system 12 has three light sources of R, G, and B (for example, fluorescent lamps) 12a, 12b, 12c and an optical system indicated by a lens 12d. The image written in the spatial light modulator 10 is sequentially illuminated with uniform light from the light sources 12a, 12b, 12c, so that the recording paper 19 is recorded by the lens 12d.
Projected on top.

When the R image is written in the spatial light modulator 10, the R light source 12a is turned on to illuminate the spatial light modulator 10, and the recording paper 19 is exposed by the reflected light. The same process is sequentially repeated for G and B color separation images. The recording paper 19 on which the R, G, and B images have been exposed in this manner
However, a color hard copy is obtained by being developed.

As with the analog writing system 11, the analog reading system 12 may use a color filter system in addition to the light source switching system. Further, three colors of cyan, yellow and magenta may be used instead of R, G and B.

The processing unit 15 is mainly composed of a computer including a microprocessor, a memory, etc., and has a light receiving element 13e.
The image signal photoelectrically converted in is received and subjected to image processing, that is, gradation processing (gamma correction, shading correction), sharpening (sharpness enhancement), area designation (trimming,
Some or all digital processing such as masking), color processing (color reproduction, paint function, cut out by color), movement (rotation), and editing processing (embedding combination, character combination) are performed. Note that the processing unit 15 does not necessarily have to perform special processing. The processing result is displayed on the display 16, and the processing can be performed interactively while confirming the result. The processed image signal is output to the laser modulation circuit 14d.

Note that the control unit 17 shown in FIG. 2 is omitted in FIG.

FIG. 3 shows a spatial light modulator which is a main component of the present invention.
FIG. 11 is a cross-sectional view showing one configuration example of 10.

In the figure, reference numerals 10a and 10b denote glass plates arranged at both ends, an electrode 10c is laminated on the entire inner surface of one glass plate 10a, and a photoconductor 10d is further laminated on the inside of the electrode 10c. ing. An electrode 10e is laminated on the entire inner surface of the other glass plate 10b.

A spacer 10f is inserted between the electrode 10e and the conductor 10d, and a liquid crystal 10g is injected and sealed in the space formed by the electrode 10e, the conductor 10d, and the spacer 10f. A power source 10h is connected to the electrodes 10c and 10e.

The electrodes 10c and 10e are transparent electrodes, and are preferably composed of an indium tin oxide (ITO) film.

As the photoconductor 10d, cadmium sulfide (CdS), cadmium telluride (CdTe), selenium (Se), zinc sulfide (Zn
S), bismuth silicate crystal (BSO), amorphous silicon, or organic photoconductor is used. When handling color images, it is best to use amorphous silicon as the photoconductor. This is because the wavelength sensitivity of amorphous silicon is flat over the entire visible light.

The photoconductor 10d changes the molecular orientation of the liquid crystal according to the input light, and other materials of the photoconductor whose resistance changes with light can be used. For example, a material that generates a voltage by light (for example, a solar cell), a material that generates heat by light, a material that changes its structure by light (for example, a photochromic compound), and the like. The material that generates heat by light and the material whose structure is changed by light have a function of directly changing the molecular orientation of liquid crystal without using electricity.

The glass plates 10a and 10b are transparent and function as substrates for sealing the liquid crystal 10g. Therefore, a transparent plastic plate or a transparent ceramic plate may be used instead of the glass plate.

A liquid crystal having a memory function is used as the liquid crystal 10g. For example, dynamic scattering type (DS) liquid crystal, phase transfer type liquid crystal, smectic A liquid crystal, ferroelectric liquid crystal and the like are used.

As an example, writing and reading operations of the spatial light modulator using the dynamic scattering (DS) liquid crystal will be described below.

When a direct current voltage or a low frequency alternating current voltage of about 100 Hz is applied to the dynamic scattering type liquid crystal, the liquid crystal undergoes dynamic scattering and becomes a white turbid state. This state is maintained and stored even if the voltage is removed. And high frequencies above the cutoff frequency (eg
When a voltage of 700 Hz) and uniform relatively strong light are applied,
The stored image is erased. This development is applied to the spatial light modulator.

Writing to the spatial light modulator 10 is performed by applying a direct current voltage or a low frequency alternating current voltage of about 100 Hz from the power source 10h between the electrodes 10c and 10e, and at the same time, transmitting the planar image light to the photoconductor 10d forming the image writing plane. An optical image is made incident by irradiation of a projected or intensity-modulated laser beam. This causes a distribution of resistance in the photoconductor 10 according to the light intensity distribution. That is, the resistance of the photoconductor 10d in the exposed part is lowered,
The portion of the photoconductor 10d that was not exposed to the light remains high in resistance. As a result, the voltage corresponding to the light intensity distribution is 10g
The liquid crystal in the portion to which the voltage is applied causes a scattering phenomenon.

For reading from the spatial light modulator 10, when uniform light is applied to the entire surface of the spatial light modulator 10, scattered light or reflected light that is modulated according to the information written in each point is obtained, An analog image can be read out by forming an image with a lens. Further, when spot light such as a laser beam is emitted, the pixel information of the spot can be read.

In order to erase the entire image written in the spatial light modulator 10, it is sufficient to irradiate the entire surface of the photoconductor 10d with uniform light while applying a high-frequency AC voltage between the electrodes 10c and 10e.

In order to partially erase the image written in the spatial light modulation element 10, a laser beam having a constant light intensity is applied to a portion to be erased of the photoconductor 10d in a state where a high frequency AC voltage is applied between the electrodes 10c and 10e. Two-dimensional scanning and uniform irradiation. This partial erasure is especially necessary when a digital image having color gradation is overwritten on an analog image.

When a liquid crystal having a memory function is used as the liquid crystal 10g, writing is not performed unless both light and voltage are applied to the photoconductor at the same time. That is, the written image does not change when the reading laser beam or uniform light is applied to the photoconductor. Therefore, it is not necessary to provide a light-shielding film between the liquid phase and the photoconductor to prevent light from being applied to the photoconductor at the time of reading, and the reading optical system can be a transmissive type. Moreover, the laser beam for reading may be applied from the glass plate 10a side or the glass plate 10b side. Further, a light-shielding film may be provided to make it a reflection type.

In particular, if the laser beam for reading is applied from the same side as that for writing, most of the optical system can be shared by the digital writing system and the digital reading system. FIG. 4 schematically shows a configuration example of a laser beam scanning mechanism in this embodiment.

As shown in the figure, the laser beam emitted from the laser light source 14a (13a) is imaged on the spatial light modulator 10 by the lenses 20 and 21. This laser beam is scanned by the laser beam scanning system 14 before being imaged on the spatial light modulator 10.
Scanned at c (13c).

The laser beam scanning system 14c (13c) includes a main scanning galvanometer 22, a sub-scanning galvanometer 23, a correction lens 24,
And the scan control unit 25. The main scanning galvanometer 22 scans the spatial light modulation element 10 for one row with respect to the laser beam spot. The sub-scanning galvanometer 23 scans the laser beam spot in a direction orthogonal to the main scanning direction. That is, when the main scanning of one row is completed, the spot is moved to the next row. As described above, the laser beam spot is two-dimensionally scanned on the spatial light modulator 10 by the main scanning galvanometer 22 and the sub scanning galvanometer 23.

The correction lens 24 has a different optical path length between the central portion and the peripheral portion of the spatial light modulator 10, and when focusing on the central portion, there is a disadvantage that the peripheral portion does not focus. Therefore, the correction lens 24 is provided to correct this. . Such a correction lens is generally called an Fθ lens.

The scanning control circuit 25 sends a control signal to the main scanning galvanometer 22 and the sub scanning galvanometer 23. The laser modulation circuit 14d and the light receiving element 13e also receive a signal from the scanning control circuit 25 and operate in synchronization with this.

The main scanning density at the time of reading depends on the sampling frequency of the light receiving element 13e. To change the main scan density,
The sampling frequency and the rotation speed of the sub-scanning galvanometer 23 may be controlled. As a result, low resolution reading and high resolution reading can be performed.

An enlarged image can be formed by reading out an arbitrary portion of the spatial light modulation element 10 with high resolution and writing the read-out signal in a region having an area larger than the area of the reading-out portion at a normal density. If the reverse is done, a reduced image can be formed.

To change the main scanning density during writing, the modulation frequency of the laser modulation circuit 14d and the rotation speed of the sub-scanning galvanometer 23 may be controlled.

In the configuration example of FIG. 4, the beam spot diameter adjusting unit 14
The b (13b) adjusts the beam spot diameter by changing the focal lengths of the lenses 20 and 21. More specifically,
The focal length is changed by moving the lens 21 in the optical axis direction. This has the same structure as a so-called zoom lens, and its drive is performed by a motor or the like.

To change the focal length of the lens 21,
There is a method of forming 21 with a material whose refractive index (or apparent refractive index) changes according to voltage, such as an electro-optical material or liquid crystal. In this method, a mechanical drive unit is not required, so that the device is small and highly reliable.

In addition, a lens array is used as the lens 21,
There is a method in which the beam spot diameter is adjusted by switching this by the degree of overlap of the multi-beams.

In any of these methods, these drive unit for changing the focal length of the lens 21, the focus variable lens, the beam array switching unit, the scanning control circuit 25, the laser modulation circuit 14d,
And the light receiving element 13e.

The beam spot diameter is controlled according to the scanning density of the spatial light modulator 10. The relationship between the scanning density of the spatial light modulator 10 and the beam spot diameter is shown in FIG.

The ratio D / p between the scanning pitch p and the beam spot diameter D is ideally controlled to be as close to 1 as possible. The ratio D / p may exceed 1 when reading. However, at the time of writing, the ratio D / p should not exceed 1.

FIGS. 5 (D), (E), and (F) show dot patterns when the beam spot diameter is kept constant despite changing the scanning density. A normal scanning density, a low resolution scanning density in FIG. 6E, and a high resolution scanning density in FIG.

Considering the time of reading, in the case of FIG. 6E, when the image written in the spatial light modulator has a spatial frequency substantially equal to the scanning pitch p, a large reading error may occur. Further, in the case of FIG. 6F, it is difficult to read an accurate image even if the scanning density is increased.

Therefore, according to the scanning density as in this embodiment, the ratio D / p
If the beam spot diameter is adjusted so as to be as close to the optimum value as possible, it is possible to obtain an image having the best image quality at the scanning density as shown in (A), (B) and (C) of FIG. Images with less error can be obtained.

FIG. 6 schematically shows another configuration example of the laser beam scanning mechanism in the present embodiment.

As shown in the figure, the laser beam emitted from the laser light source 14a (13a) is converted into parallel light by the lens 26, reflected by the mirror 27, and reflected by the hologram disc 28.
Is made incident on. And this hologram disc
Deflection in the main scanning direction is performed by 28, and deflection in the sub scanning direction is performed by the galvanometer 29. The hologram disk 28 also has a lens function, whereby the laser beam is imaged on the spatial light modulator 10 and is two-dimensionally scanned.

The light modulated by the spatial light modulation element 10 passes through a path opposite to that at the time of incidence, that is, passes through the galvanometer 29 and the hologram disk 28, is condensed by the lens 13d, and is applied to the light receiving element 13e.

The scanning control circuit 30 sends a control signal for the hologram disc 28 and the galvanometer 29. The laser modulation circuit 14d and the light receiving element 13e also receive a signal from the scanning control circuit 30 and operate in synchronization with this.

In this configuration example, a method of changing the wavelength of the laser beam emitted from the laser light source 14a (13a) is used as a method of adjusting the beam spot diameter.

Focal length F of convergent light at the time of recording on the spatial light modulator 10
₁ , the wavelength λ ₁ , the focal length F ₂ of the reproduction light at the time of reproduction, and the wavelength λ ₂ have the following relationship.

_{F 1 · λ 1 = F 2} · λ 2 Therefore, if you the F ₁ and lambda ₁ constant changing lambda _2, change the focal length F ₂ of the reproducing light, it is possible to adjust the beam spot diameter. If the laser light source 14a (13a) is a semiconductor laser, the wavelength λ ₂ can be changed by changing the applied voltage.

As shown in FIG. 7, hologram lenses 28a and 28b recorded with convergent light having different focal lengths F ₁ or different wavelengths λ ₁ are concentrically fixed to the hologram disc 28,
The laser beam may be selectively passed through the hologram lens 28a or 28b by moving the mirror 27 or the hologram disk 28. When recording with light with a fixed wavelength λ ₁ and different focal lengths F ₁ , by changing F 1 with constant λ ¹ and λ 2 in the above equation,
It means controlling F2. Further, when recording is performed with light having different focal lengths F1 and different wavelengths λ1, it means that F ₂ is controlled by changing λ1 with constant F1 and λ2.

In the example of FIG. 6, it goes without saying that the various methods described above may be used as the method of adjusting the beam spot diameter.

FIG. 8 is a flow chart schematically showing a part of a computer control program provided in the control unit 17 shown in FIG. This program is for color image editing
The output function mode is executed, and when this mode is designated, the computer operates as follows.

First, in step S1, a flag n for switching between R, G and B is initialized to n ← 0. Next, in step S2, it is determined whether or not n = 0.

If n = 0, the analog writing system 11 is executed in step S3.
The R light source 11a is turned on, and in the next step S4, the document 18
The optical image of the uniform light from the R light source 11a
Write to the spatial light modulation element 10 via.

If n = 0 is not satisfied in step S2, it is determined in step S5 whether n = 1. In the case of n = 1, the G light source 11b is turned on in step S6, and in the next step S4, an optical image of the uniform light from the G light source 11b of the document 18 is transmitted through the lens 11d to the spatial light modulator. Write to 10. If n = 1 is not satisfied, the light source 11c of B in step S7
Is turned on, and in the next step S4, the B light source 11c of the document 18 is
An optical image of uniform light from is written in the spatial light modulator 10 via the lens 11d.

In the next step S8, the digital read system 13 is activated. That is, the spatial light modulator 10 is two-dimensionally scanned with the laser beam emitted from the laser light source 13a,
By applying the transmitted light, reflected light, or scattered light to the light receiving element 13d, the image information written on the spatial light modulation element 10 is read.

Next, in step S9, the processing unit 15 is operated to perform various image processing on the read image information.

In the next step S10, the digital writing system 14 is activated. That is, the signal from the processing unit 15 is supplied to the laser modulation circuit 14
applied to c to modulate the laser beam and spatial light modulator 1
0 is two-dimensionally scanned and writing is performed. At the time of this digital writing, the digital image may be written on the entire spatial light modulation element 10, or the digital image may be written on a part thereof. This makes it possible to obtain an image in which analog images and digital images are mixed and fused.

In step S11, it is determined whether or not the image processing by the processing unit 15 is completed, and if not, steps S8 to S10.
Is repeatedly executed.

In the next step S12, it is determined whether or not n = 0. If n = 0, the process proceeds to step S13 to turn on the R light source 12a of the analog reading system 12. Then, in the next step S14, the image information written on the spatial light modulator 10 is read by the uniform light from the R light source 12a, and the optical image is exposed on the recording paper 19 via the lens 12d. .

If n = 0 is not satisfied in step S12, it is determined in step S15 whether n = 1. In the case of n = 1, the G light source 12b is turned on in step S16, and in the next step S14, the image information written on the spatial light modulator 10 is converted into uniform light from the G light source 12b. reading,
The optical image is exposed on the recording paper 19 via the lens 12d.
If n = 1 is not satisfied, the B light source 12c is turned on in step S17, and in the next step S14, the image information written on the spatial light modulation element 10 is uniformly illuminated from the B light source 12c. And the optical image is exposed on the recording paper 19 via the lens 12d.

Next, in step S18, n is incremented by n ← n + 1, and then in step S19, it is determined whether or not n = 3. In the case of n = 3, this program is terminated assuming that the processing of all the colors of R, G, B has been completed. n = 3
If not, the process returns to step S2 to repeat the above-mentioned processing.

When the color image editing function mode is instructed, the computer executes only the processes of steps S8 to S11 of the program shown in FIG. However, the processes of steps S8 to S11 are repeatedly executed for all R, G, and B colors.

When the image shana function mode is designated, only the processes of steps S1 to S8 of the program shown in FIG. 6 are executed. Also in this case, it is repeatedly executed for all the colors of R, G, and B. That is, the process is repeated until n = 3.

When the printer function mode is instructed, step S20 of the program shown in FIG. 8 is first executed, and image information is input from the control unit 17 or other external device. Next, the processing of step S10 and subsequent steps is executed. However, these processes are repeatedly executed for all R, G, and B colors.

When the analog copy function mode is instructed, the processing is executed so as to always jump from step S4 to step S12 of the program shown in FIG.

According to the present embodiment, analog processing or digital processing can be selectively used depending on the type of image. For example, in a line drawing or a character-centered image, a smooth line can be reproduced by instructing the analog copy function mode and performing analog processing. Further, for an image in which color is emphasized, color correction can be performed by instructing a color image editing / output function mode, and color can be faithfully reproduced.

Area separation of an image, which is difficult with analog processing, can be easily processed by instructing the color image editing / output function mode or the color image editing function mode and performing digital processing such as partial erasing. It is also possible to obtain an image in which an analog image and a digital image are mixed and fused such that an analog image is embedded in a digital image, a digital image is embedded in an analog image, or a digital image is overwritten on an analog image.

As described in detail above, according to the present invention, the means for variably controlling the scanning density of the laser beam to a desired value and the beam spot diameter of the laser beam according to the controlled scanning density. When the scanning density of the laser beam in the digital reading system and the digital writing system is changed, the best image quality can be obtained with the scanning density and an image with less error can be output. An image processing device can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic structure of a color image editing / outputting apparatus as one embodiment of the present invention, FIG. 2 is a block diagram schematically showing the configuration of the embodiment of FIG. 1, and FIG. FIG. 4 is a sectional view showing an example of the structure of the spatial light modulator, FIG. 4 is a schematic view of an example of the structure of the laser beam scanning mechanism in the embodiment of FIG. 1, and FIG. 5 shows a dot pattern of the spatial light modulator. FIG. 6 is a schematic diagram of another configuration example of the laser beam scanning mechanism in the embodiment of FIG. 1, FIG. 7 is a configuration diagram of a hologram disk, and FIG. 8 is a computer of the embodiment of FIG. 3 is a flowchart schematically showing a part of the control program of FIG. 10 ... Spatial light modulator, 10a, 10b ... Glass plate, 10c, 1
0e …… electrode, 10d …… photoconductor, 10f …… spacer, 10g
...... Liquid crystal, 10h ...... Power supply, 11 ...... Analog writing system, 1
1a, 11b, 11c, 12a, 12b, 12c ... Light source, 11d, 12d, 13
d, 20, 21, 26 ... Lens, 12 ... Analog readout system, 13 ... Digital readout system, 13a, 14a ... Laser light source, 13b, 14b ... Beam spot diameter adjustment unit, 13c, 14c ...
… Laser beam scanning system, 13e… Light receiving element, 14… Digital writing system, 14d… Laser modulation circuit, 15… Processing section, 16… Display, 17… Control section, 18… Original,
19 …… Recording paper, 22,23,29 …… Galvanometer, 24 ……
Correction lens, 25, 30 ... Scan control circuit, 28 ... Hologram disk, 28a, 28b ... Hologram lens.

Claims (1)

(57) [Claims] 1. A spatial light modulator comprising a photoconductor forming an image writing plane, a liquid crystal laminated on the photoconductor, and electrodes sandwiching the photoconductor and the liquid crystal, and an original image in the space. An analog writing system for writing in the light modulation element in an analog manner, and a digital reading system for digitally reading an image written in the spatial light modulation element by two-dimensionally scanning a laser beam on the spatial light modulation element, A processing unit that performs image processing on the read image data, a digital writing system that digitally writes the processed image data in the spatial light modulator by two-dimensionally scanning a laser beam, and the spatial light modulator. An analog reading system for reading the image written in the image in an analog manner, and means for variably controlling the scanning density of the laser beam to a desired value The image processing apparatus characterized by comprising a means for adjusting a beam spot diameter of the laser beam according to the scanning density was the control.