JPH06266274A - Formation of holographic stereoscopic hard copy and device - Google Patents

Abstract

(57) [Summary] [Object] The present invention can be used as a hard copy of a three-dimensional object, and is a holographic three-dimensional hard image with good image quality
The main purpose is to obtain a copy. According to the present invention, an original image corresponding to a coordinate position of a condensing portion on a hologram dry plate is created, the original image is displayed on display means, and a dot-shaped element corresponding to the original image is formed on the hologram dry plate by using an optical system. Forming a hologram, sequentially moving and displaying the coordinate position of the condensing part on the hologram dry plate, and forming an element hologram are repeated to form a plurality of dot-shaped element holograms on the hologram dry plate. The feature is that element holograms are formed while applying phase modulation to the condensed object light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing a holographic three-dimensional hard copy which can be used as a hard copy of a three-dimensional object and has a high image quality.

[0002]

2. Description of the Related Art Today, three-dimensional image processing technology is widely used. For example, in the medical field, X-ray CT
(Computed Tomography), MRI (Magnetic Resonannce I
3D information of the human body is collected by using (maging) etc. and is used for diagnosis and surgery planning. In addition, a three-dimensional CAD system is used for construction, product design, and the like. At present, photographs such as two-dimensional tomographic images and projected images are used as the hard copy output from these three-dimensional image processing systems. However, as a more efficient and easy-to-understand item, a hard copy that expresses a three-dimensional object with a planar object has been desired.

By the way, a holographic stereogram (hereinafter referred to as HS) is the most excellent as a hard copy capable of stereoscopically displaying a three-dimensional object processed and generated by a computer. This HS synthesizes a plane image of an object viewed from various angles into one hologram, and is suitable for three-dimensional recording and display of a fictitious object.

However, no HS method satisfying the conditions as a hard copy of a three-dimensional object has been reported until now. In the conventional method, the vertical parallax cannot be recorded, and the reproduced image is distorted depending on the observation position. Moreover, the hologram cannot be automatically recorded by the method of combining in two steps. Multiplex holograms and Al
Although cove Hologram and others have been proposed, these are not only not able to record the vertical parallax information, but also
Since it is a cylindrical type or a semi-cylindrical type and requires a reproducing device for observation, it is not suitable for general hard copy.

On the other hand, recently, a hard copy with high image quality is provided.
Although there is a strong demand for it, it is currently difficult to create a hologram with high image quality.

[0006]

As described above, according to the conventional method, the vertical parallax cannot be recorded, so that the reproduced image is distorted depending on the observation position, or the stereoscopic hologram is automatically generated. However, there is a problem that it is not possible to record the image or it is not possible to create a hologram with high image quality.

It is an object of the present invention to provide a method and apparatus for producing a holographic three-dimensional hard copy which can be used as a hard copy of a three-dimensional object and has a high image quality.

[0008]

In order to achieve the above object, in the method for producing a holographic three-dimensional hard copy of the present invention, an original image corresponding to the coordinate position of the condensing portion on the hologram dry plate is produced. A step, a step of displaying an original image corresponding to the coordinate position of the condensing portion on the hologram dry plate on the display means, a step of forming a dot-shaped element hologram corresponding to the original image on the hologram dry plate using an optical system,
The steps of sequentially moving and displaying the coordinate position of the condensing part on the hologram dry plate and forming the element hologram are repeated to form a plurality of dot-shaped element holograms on the hologram dry plate. Element holograms are formed by applying phase modulation to the emitted object light.

In order to achieve the above object, the holographic three-dimensional hard copy producing apparatus of the present invention comprises:
Moving means for moving the hologram dry plate to a desired position,
An original image creating means for obtaining an original image pattern corresponding to each point on the hologram dry plate from the three-dimensional image data, a display means for displaying the original image pattern, and an original image pattern displayed on the display means.
An optical system for forming a dot-shaped element hologram corresponding to an image on a hologram plate, a developing means for developing a hologram plate having a plurality of element holograms formed thereon, a moving means, an original image forming means, and a developing means. It comprises a control means for creating a graphic three-dimensional hard copy and a phase modulation means arranged on the optical path of the object light focused on the hologram dry plate and for applying phase modulation to the object light. .

Here, in particular, the phase modulation means is arranged immediately before or after the display means.

The phase modulating means may be a diffuser whose phase changes randomly, or a pseudo-random phase sequence consisting of four phase levels (0, π / 2, π, (3/2) π). The pseudo random diffuser has a phase difference (absolute value) between the most adjacent terms as a constant value.

Further, the display means may be an amplitude modulation element such as a liquid crystal panel, and the hologram dry plate is preferably a Lippmann hologram dry plate.

[0013]

Therefore, in the method and apparatus for producing a holographic three-dimensional hard copy of the present invention, it is a flat type
By combining in steps and recording the parallax information in the vertical direction, a stereoscopic image can be accurately recorded and displayed.

Further, in the producing method and apparatus of the present invention,
By sequentially recording dot-shaped element holograms on the surface of the base material, it is possible to perform recording in a manner similar to that of a conventional dot printer.

Further, in the manufacturing method and apparatus of the present invention, the intensity change in the element hologram is reduced by applying the phase modulation to the object light focused on the hologram dry plate to form the element hologram. Since most of the area is within the proper exposure area, the size of the element hologram can be reduced, and high density recording of the element hologram becomes possible. As a result, it is possible to create a hologram with good image quality and inconspicuous dots.

From the above, the three-dimensional data hard copy
The method of the present invention is optimal for realizing a 3-D printer as a machine.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

First, the principle of the present invention will be described with reference to FIGS. 1 and 2 in the case where a Lippmann type hologram is used as a hologram.

The production method of the present invention shown in FIG. 2 is similar to the method of recording parallax information in the conventional multiplex hologram shown in FIG. 1, but the multiplex hologram is Whereas only the parallax in the direction is recorded, the method of the present invention records the parallax information also in the vertical direction. In this method, a thick hologram is used to form a Lippmann hologram so that the light to be reproduced has wavelength selectivity, and the vertical parallax is reproduced by white light illumination.

Next, the optical system used in the manufacturing method of the present invention will be described with reference to FIG.

An image pattern created by a computer is displayed on the liquid crystal panel 10 which is an amplitude modulation element, and the transmitted light (object light) is a pseudo random diffusion plate 18 which is a phase modulation element.
Phase modulation is performed via the lens 12, and the light is focused on the hologram surface (hologram dry plate) 14 via the lens 12. Further, the reference light is made incident on the condensing portion 16 from the opposite direction, and the interference fringe pattern with the reference light is recorded on the hologram surface 14 as a dot-shaped element hologram. Then, the hologram film is moved little by little in the vertical and horizontal directions for sequential exposure to expose the entire hologram surface with dot-shaped element holograms.

Here, the pseudo-random diffuser 18 has a pseudo-random phase sequence consisting of four phase levels (0, π / 2, π, (3/2) π), and the phase difference between the most adjacent terms. Only (absolute value) is a constant value.

The original image pattern displayed on the liquid crystal panel 10 is created by perspective projection conversion as shown in FIG. The center point of the projection is the pattern 1
It is a point on the hologram surface 14 where 0 is exposed, and by the aperture and focal length of the lens 12 in the optical system shown in FIG.
The range of rays to be calculated is determined. The difference from the general computer graphics method is that the center point of projection and the viewpoint are different. Therefore, the hidden surface removal process is performed with the right side in the front in FIG. This is to calculate the direction and intensity of the light ray that passes through a certain point on the hologram surface 14 among the reflected light rays from the object.

In HS recording, light rays are condensed in the same direction as in the original pattern calculation and recorded as a Lippmann hologram. The hologram film is moved in the vertical and horizontal directions, and as shown in FIG. 4, the hologram film 14 is exposed so that the entire hologram surface 14 is filled.

Next, the principle of the hologram reproducing method of the present invention will be described.

When the HS recorded as described above is reproduced,
As shown in FIG. 5, the rays from each point on the hologram surface 14 are correctly reproduced, and a stereoscopic image can be observed.
In other words, the hologram 14 is used as a window, and the directions and intensities of all the rays that pass through the window are correctly recorded.
It is something to play. Therefore, the method of the present invention can reproduce a stereoscopic image without any distortion.

Next, with reference to FIG. 6, a stereoscopic image forming system using the one-step Lippmann HS will be specifically described.

FIG. 6 is a schematic diagram showing a concrete example of the configuration of the system. In FIG. 6, helium neon ray
The laser beam from the laser 20 is separated into object light and reference light by a beam splitter 22. Of these, the object light becomes parallel light through the lens 24, and the liquid crystal panel 10
Are lit, and the liquid crystal panel 10 performs amplitude (intensity) modulation. Further, the amplitude-modulated object light is phase-modulated by the pseudo-random diffusion plate 18. Then, the phase-modulated object light is guided to a spherical lens 34 having a large power through a lens 26, a slit 28, a lens 30, and a mirror 32, and is collected on the hologram surface 14 by the lens 34. Be illuminated. Here, the lens 26, the slit 28, and further the lens 30 constitute a spatial filtering system for removing the matrix structure of the liquid crystal panel 10.

On the other hand, the hologram surface 14 has an XY station.
It is fixed to the jig 36 and is movable in the vertical and horizontal directions. Then, while changing the information of the liquid crystal panel 10, the XY stage 36 is moved to form a dot-shaped element hologram on the entire surface of the hologram surface 14. The entire system is controlled by a personal computer. As the sensitive material used for the hologram surface 14, for example, a silver salt sensitive material can be used.

Next, the HS according to the present invention has the following features.

(A) A parallax in the horizontal and vertical directions can be added, and a stereoscopic image can be displayed accurately.

(B) If a Lippmann type hologram is used, it is basically possible to realize a real color.

(C) It can be synthesized by a small apparatus without using a special optical component such as a cylindrical lens.

(D) When creating a large hologram,
It is only necessary to use the exact same optical system and increase the number of exposure points.

(E) Since the light beam is condensed and used, the power of the light source can be effectively used, and high stability of the optical system is not required.

(F) Since it can be synthesized in one step, it can be used in an automatic system.

(G) For the object light focused on the hologram surface 14, the pseudo-random diffusion plate 1 which is a phase modulation element.
Since the element hologram is formed by applying the phase modulation by 8, the intensity change in the element hologram becomes small, and most of the portion enters the proper exposure area. Therefore, the size of the element hologram can be reduced, and high density recording of the element hologram becomes possible. As a result, it is possible to create a hologram with good image quality and inconspicuous dots.

Next, referring to FIGS. 7 and 8, an example of the configuration of the holographic three-dimensional hard copy producing apparatus (printer) according to the present invention will be described.

By using the HS of the present invention, it is possible to realize a practical holographic printer which outputs a hard copy of a fictitious three-dimensional object. FIG. 7 is a schematic diagram showing the system. This printer is a video
It is used in an image like a three-dimensional version of a printer. The operator can obtain a three-dimensional hard copy of the three-dimensional object by observing the three-dimensional object from various angles on the monitor and setting the output direction.

That is, first, in step A of FIG. 8, three-dimensional image data is input to the host computer 40.

Next, in step B, the hologram dry plate 14 is moved by the film moving controller 46 to set the hologram dry plate 14 at a desired position.

Next, in step C, the graphic processor 42 calculates the original image pattern for exposing each point of the hologram from the original three-dimensional data,
It is stored in the frame memory 44.

Next, in step D, the liquid crystal panel 1
The original pattern is displayed at 0.

Next, in step E, the shutter of the optical system 48 is opened to expose the liquid crystal panel 10. The laser light extracted from the laser device 20 is divided into object light and reference light by the beam splitter 22, and the object light is amplitude-modulated by the original image pattern of the liquid crystal panel 10 and further pseudo random. The light is phase-modulated by the diffusing plate 18, is condensed on the hologram surface 14, and forms one element hologram together with the reference light.

Next, at step F, the hologram dry plate 14 is sequentially moved by the film moving controller 46, and is exposed so as to fill the entire hologram surface 14 through step G.

Then, in step H, the developing process of the hologram 14 is performed by the developing machine 50, and the hologram is automatically created.

The graphic processor 42, the film moving controller 46, and the developing machine 50 are C
It is controlled by the PU.

By using such a holographic / three-dimensional printer system, it is possible to completely automatically create a three-dimensional hard copy having a high image quality, and to make a hologram of a three-dimensional object. It can be widely used as a copy.

As described above, in this embodiment, an original image corresponding to the coordinate position of the light converging portion on the hologram surface 14 is created, and this original image is displayed on the liquid crystal panel 10 which is the display means, and the optical system is used. To form a dot-shaped element hologram corresponding to the original image on the hologram surface 14 and
Forming a plurality of dot-shaped element holograms on the hologram surface 14 by repeating the sequential movement and display of the coordinate position of the upper light collecting portion and forming the element holograms,
The element hologram is formed by subjecting the object light focused on the hologram surface 14 to phase modulation by a pseudo-random diffusion plate 18 which is a phase modulation element.

Therefore, the following various effects can be obtained.

(A) Since a plurality of minute dot-shaped element holograms having three-dimensional image information are formed in the holographic three-dimensional hard copy according to this embodiment, a three-dimensional stereoscopic image having a parallax in the vertical direction is also formed. Hard copy can be obtained. Also, since the image can be reproduced by the dot-shaped element hologram, there is no limitation on the size of the hologram,
There is no unevenness on the entire surface of the hologram.

(B) According to the producing method of this embodiment, a three-dimensional hard copy can be produced by one optical system, and an automatic hard copy system can be realized. Also,
Laser light can be effectively used and the exposure time is short, so that it is not affected by external vibration.

(C) According to the hologram creating apparatus (printer) of this embodiment, the holographic three-dimensional hard copy is used.
Can be created automatically.

(D) A holographic three-dimensional hard copy having a good image quality can be automatically created.

That is, when the pattern of the liquid crystal panel 10 is illuminated with parallel light and condensed by the lens 12 to record the element hologram, in order to reduce the size of the element hologram, the element hologram is replaced by the lens 12. It is necessary to shoot near the focal position of. If each element hologram is made small and its density is increased in order to improve the image quality, as shown in FIG. 9, the strength of the central portion of the element hologram is high and the strength of the peripheral portion is weak. Therefore, there are few portions of the hologram that enter the appropriate exposure area of the recording material, and the image quality deteriorates. Therefore, the size of the element hologram cannot be reduced.

In this regard, in this embodiment, the hologram surface 14
Phase modulation is applied to the object light that is focused on by the pseudo-random diffusion plate 18 that is a phase modulation element to form an element hologram, so while suppressing the effect of speckle,
It is possible to reduce the change in light intensity within the element hologram, and as shown in FIG. 9, most of the light enters the proper exposure area. Therefore, the size of the element hologram can be reduced, and high density recording of the element hologram becomes possible.

That is, the dots of the multi-dot hologram can be made small, the hologram can be recorded at a high density, and a hologram of good image quality with no conspicuous dots can be created.

The present invention is not limited to the above embodiments, but can be modified in various ways as follows without departing from the spirit of the present invention.

(A) In the above embodiment, four phase levels (0, π / 2, π, (3/2)) are used as the phase modulation element.
The case where the pseudo-random diffuser plate 18 having a pseudo-random phase sequence consisting of π) and having only the phase difference (the absolute value) between the most adjacent terms as a constant value is used has been described. Alternatively, a diffusing plate having a variable phase or other phase modulating element may be used.

(B) In the above embodiment, the case where the pseudo random diffusion plate 18 which is a phase modulation element is arranged immediately after the liquid crystal panel 10 which is an amplitude modulation element has been described.
Not limited to this, even if the pseudo-random diffusion plate 18 is arranged immediately in front of the liquid crystal panel 10 or at any other position on the optical path of the object light, the same effect as described above is obtained. The effect can be obtained.

(C) In the above embodiment, as the display means,
The case where the liquid crystal panel 10 which is the amplitude modulation element for modulating the laser light by the original image pattern is used has been described, but the present invention is not limited to this, and the number of pixels is 256 × 256 or more for use in this system. Therefore, an amplitude modulation element capable of expressing 8-bit gradation and capable of displaying an image with low noise even in coherent light illumination is preferable. For example, a mask may be used.

(D) In the above embodiment, the case where the Lippmann hologram dry plate is used as the hologram dry plate has been described, but the present invention is not limited to this, and other hologram dry plates may be used.

(E) In the above embodiment, the silver salt sensitive material was used as the sensitive material, but it is also possible to use a polymer photosensitive material for recording a Lippmann hologram with high image quality.

[0064]

As described above, according to the present invention, an original image corresponding to the coordinate position of the condensing portion on the hologram dry plate is created, this original image is displayed on the display means, and the hologram dry plate is used by using the optical system. A dot-shaped element hologram corresponding to the original image is formed by repeatedly moving and displaying the coordinate position of the condensing part on the hologram dry plate and forming the element hologram to form a plurality of dot-shaped element holograms. Since it is formed on the hologram dry plate and the element hologram is formed by applying phase modulation to the object light condensed on the hologram dry plate, it can be used as a hard copy of a three-dimensional object and has high image quality. A method and apparatus for producing a good holographic three-dimensional hard copy can be provided.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of a conventional multiplex hologram.

FIG. 2 is a diagram for explaining the principle of the multi-dot hologram of the present invention.

FIG. 3 is a schematic diagram showing an optical system of a one-step Lippmann HS according to the present invention.

FIG. 4 is a diagram for explaining a method of creating an original image pattern used in the present invention.

FIG. 5 is a diagram for explaining a hologram reproducing method of the present invention.

FIG. 6 is a schematic diagram showing a detailed optical system for Lippman HS synthesis according to the present invention.

FIG. 7 is a schematic diagram showing a configuration example of a holographic printer system of the present invention.

8 is a flowchart of the holographic printer system in FIG.

FIG. 9 is a diagram for explaining the function and effect of the hologram of the present invention.

[Explanation of symbols]

10 ... Liquid crystal panel, 12, 24, 26, 30, 34 ... Lens, 14 ... Hologram surface, 16 ... Condensing part, 18 ... Pseudo-random diffusion plate, 20 ... Laser, 22 ... Beam splitter, 28 ... Slit, 32 ... Miller, 36 ... XY stage, 40 ... Host computer, 42 ... Graphic processor, 44 ... Frame memory, 46 ... Film moving controller, 48 ... Optical system, 50 ... Developing machine.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Susumu Takahashi 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Kazuo Honda 1913-12 Kitahasakucho, Midori-ku, Yokohama-shi, Kanagawa (72) Masahiro Yamaguchi 4-1-131-502 Kamada, Setagaya-ku, Tokyo (72) Inventor Nagaaki Oyama 2-3-9 Kannon, Kawasaki-ku, Kawasaki-shi, Kanagawa (72) Hideaki Endo Kitamamagome, Ota-ku, Tokyo 1-18-8

Claims (7)

[Claims] 1. A holographic three-dimensional hard copy formed by forming a plurality of dot-shaped element holograms on the surface of a base material.
In the method of creating, a step of creating an original image corresponding to the coordinate position of the light collecting portion on the hologram dry plate, a step of displaying the original image corresponding to the coordinate position of the light collecting portion on the hologram dry plate on the display means, Forming a dot-shaped element hologram corresponding to the original image on the hologram dry plate using an optical system, sequentially moving the coordinate position of the condensing part on the hologram dry plate to display, and forming the element hologram The step of forming a plurality of dot-shaped element holograms on the hologram dry plate by repeating the step of forming the element hologram while applying phase modulation to the object light focused on the hologram dry plate. The holographic three-dimensional hard copy characterized by
How to create. 2. A holographic three-dimensional hard copy formed by forming a plurality of dot-shaped element holograms on the surface of a base material.
In the producing apparatus, the moving means for moving the hologram dry plate to a desired position, the original image producing means for obtaining the original image pattern corresponding to each point of the hologram dry plate from the three-dimensional image data, and the original image pattern Means for displaying, an optical system for forming dot-shaped element holograms corresponding to the original pattern displayed on the display means on the hologram dry plate, and developing the hologram dry plate having a plurality of the element holograms formed thereon. Developing means, a control means for controlling the moving means, the original image creating means, and the developing means to create a holographic three-dimensional hard copy, and on the optical path of the object light focused on the hologram dry plate. A holographic three-dimensional hard copy, which is provided with phase modulation means for applying phase modulation to the object light. Of creating apparatus. 3. The holographic three-dimensional hard copy producing apparatus according to claim 2, wherein the phase modulation means is arranged immediately before or after the display means. 4. The holographic three-dimensional hard copy producing apparatus according to claim 2, wherein the phase modulating means is a diffuser plate whose phase changes at random. 5. The phase modulation means has a pseudo-random phase sequence consisting of four phase levels (0, π / 2, π, (3/2) π), and the phase difference between the nearest terms (that Absolute value)
The holographic solid copy making apparatus according to claim 2 or 3, which is a pseudo-random diffusion plate having only a constant value. 6. The holographic three-dimensional hard copy producing apparatus according to claim 2, wherein the display means is an amplitude modulation element such as a liquid crystal panel. 7. The holographic three-dimensional hard copy producing apparatus according to claim 2, wherein the hologram dry plate is a Lippmann hologram dry plate.