JPH0252387A - Holographic stereogram - Google Patents

Abstract

PURPOSE:To allow repetitive reconstruction of stereoscopic images simultaneously with writing of information by constituting a recording medium for recording the information on holograms of a material which allows rerecording. CONSTITUTION:The recording medium 63 to be recorded with interference fringes is formed of the material which allows rerecording to a cylindrical shape. For example, a photochromic material, thermoplastic, magneto-optical material or ferroelectric material is used as the material which allows rerecording. The interference fringes by interfering the signal waves transmitted through the respective continuous images which are different in visual line directions with respect to an object and the reference waves 31a which does not transmit the images. The hologram is formed by recording the interference fringes on the recording medium 63. The material of the recording medium 63 for forming the hologram is constituted of the material which allows rerecording so that the interference fringes, i.e. the information on the hologram can be easily recorded. The easy formation of the hologram is possible in this way and the rewriting of the information on the hologram is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a holographic stereogram, and particularly to a holographic stereogram in which information related to the hologram can be rewritten.

(Prior Art) Conventionally, a so-called bolographic threogram is known as a method for displaying a target object three-dimensionally.

This involves sequentially photographing the object to obtain a three-dimensional image from different angles in the viewing direction, and then synthesizing one hologram based on the many two-dimensional photographs obtained through these photographs to create a three-dimensional display. It comes out.

As one of such conventional holographic stereograms, a white light reproduction cylindrical holographic stereogram, a so-called multiplex hologram, which uses a white light source as illumination light for reproduction illumination, is widely used for various displays. ing.

Next, conventional multiplex holograms are shown in Figures 2 and 3.
This will be explained with reference to the figures and FIG.

First, to explain the case of creating a multiplex hologram, as shown in FIG.
is placed on the rotary table 103, and the rotating table 103 is rotated in a constant direction at a constant speed to rotate the target object 1.
01 is continuously imaged by a movie camera 105. Therefore, the original film 107, which is the film of the movie camera 105, contains planar images taken at different photographing angles according to the rotation of the target object 101, as well as a plurality of consecutive planar images of the target object 101 taken in different observation directions. Each frame is recorded.

Next, as shown in FIG. 3, laser light is sequentially projected onto each frame of the original film 107 through a lens 121. Here, the lens 121, the projection lens 123,
Field lens 125, cylindrical lens 127 and slit 12
9a are arranged on the optical axis P, and the laser light transmitted through the original film 107 advances to the slit 129a via the projection lens 123, field lens 125, and cylindrical lens 127. At this time, the slit 129a formed in the slit plate 129 is irradiated with the reference light 131a from the reference light source 131, and this reference light 131a interferes with the signal light, that is, the laser light transmitted through the original film 107 described above. Generate interference fringes. The interference fringes are drawn out into long and thin stripes through the slits 129a and sequentially recorded on the hologram film 133 to create a hologram 133a.

In addition, an original movie film 107 as shown in FIG.
When using the hologram 133a, it takes time to create the hologram 133a, so to solve this problem, the original film 10
In place of 7, a so-called spatial light modulator, such as a liquid crystal television receiver, has been proposed to create a hologram. (Synthesis of bolographic stereograms using liquid crystal TV, Proceedings of the 35th Applied Physics Association Conference, Volume 3, p. 763, 1988
2003) When this liquid crystal television receiver is used, it has the characteristics that the display panel is a transmissive type and that images can be transmitted by video signals.

Next, the case where a three-dimensional image is reproduced from the hologram 133a created in this manner will be explained with reference to FIG.

=4 As shown in FIG. 4, the hologram 133a is formed into a cylindrical shape, and white light from a white light source 141 is irradiated from above the cylindrical hologram 133a. By observing the cylindrical hologram 133a from the side while slowly rotating the cylindrical hologram 133a in a certain direction, a three-dimensional reconstructed image 143 with rainbow colors emerging within the cylinder of the cylindrical hologram 133a can be seen. can be obtained.

In the multiplex hologram shown above,
Three-dimensional images can be easily reproduced by illumination with ordinary white light, and people who cannot record information related to holograms by directly irradiating laser light or J! II etc. can be created as a hologram and reproduced three-dimensionally.

Furthermore, the movement of the target object 101 is not limited to a stationary object, but can be recorded and reproduced as long as it moves slowly.

(Problems to be Solved by the Invention) However, in the conventional multiplex hologram described above, a photographic film is used as a recording medium, so after recording interference fringes on the film, it is developed. It requires so-called photographic processing such as fixing the information on the hologram, washing it with water, and drying it, and requires processing with various chemicals and equipment such as a darkroom. Therefore, it has the disadvantage that it takes time and effort to obtain a desired three-dimensional reconstructed image.

Furthermore, the conventional photographic film used for creating holograms has the disadvantage that once it has been developed, information relating to other holograms cannot be recorded again.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a bolographic stereogram in which a hologram can be easily created and information related to the hologram can be rewritten.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the holographic stereogram provided by the present invention combines signal waves transmitted through successive images of an object in different viewing directions. , in a bolographic stereogram in which a hologram is created by recording interference fringes obtained by interfering with a reference wave that does not pass through the image on a recording medium, the recording medium is made of a re-recordable material; It is characterized by

(Function) The present invention generates interference fringes by interfering between a signal wave that has passed through successive images of a target object in different viewing directions and a reference wave that does not pass through the images, and stores these interference fringes on a recording medium. Record and create holograms. At this time, the material of the recording medium for creating the hologram is made of a re-recordable material, so that the interference fringes, that is, the information related to the hologram can be easily re-recorded.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

First, to explain the configuration, a hologram recording device 20 formed by an optical system such as a lens is arranged along an optical axis P of laser light. To explain specifically, there is a lens 21 on the projection side and a projection lens 2 at the focal point of this lens 21.
3 are arranged. Further, on the imaging side, a field lens 25, which is a spherical lens with a long focal length, and a cylindrical lens 27, which is a cylindrical lens with a short focal length, are arranged close to each other. Also, the slit plate 29
A slit 29a having a width of 1n+n+ and a length of about 3001 m is formed in the slit 29a. This slit 29a is arranged at the focal point of the optical system consisting of the field lens 25 and the cylindrical lens 27 described above, and is arranged perpendicular to the optical axis P.

A spatial modulator 51 is provided between the lens 21 and the projection lens 23.
is located. This spatial modulator 51 is formed of, for example, a liquid crystal television receiver, and is arranged so that the display panel of the liquid crystal television receiver is orthogonal to the optical axis P. Further, this display panel is of a transmissive type, and, for example, an image signal for each frame, that is, a video signal is supplied from the image control section 53. Therefore, when the spatial modulator 51 receives the video signal from the image control section 53, it displays on the display panel images for each frame, that is, continuous images of the object in different viewing directions. As described above, since this display panel is of a transmission type, laser light passes through the display panel and advances to the slit 29a. This slit 2
Reference light 31a from a reference light source 31 is irradiated onto 9a.

Therefore, the reference light source 3 which is the reference wave at the slit 29a
1 and a spatial modulator 51 which is a signal wave.
The transmitted laser light interferes with the laser beam, and interference fringes are generated.

A recording medium 63 for recording the interference fringes is made of a re-recordable material and is formed into a cylindrical shape. This re-recordable material may be, for example, a photochromic material, a thermoplastic, a magneto-optical material, or a ferroelectric material. (Literature, Holography - p. 70, Institute of Electronics and Communication Engineers, Corona Publishing, published in 1972) An example will be explained in which the recording medium 63 is constructed using, for example, a photochromic material among the various materials mentioned above. Here, the photochromic material has the characteristic that its transmittance changes depending on the incident light, and when the light irradiation stops, it returns to the state before the irradiation. As an example of using such a photochromic material, for example, "photochromic glass" has been put to practical use in glass, window glass, and the like. (Literature, information functional materials, materials science, VO
L, 18, NOl, 1981) Other examples include photochromic plastics, organic materials such as spiropyran and fulgide, and optical bistable devices using CuCl or GaAS, which are known as nonlinear optical media. ”
(Reference, Optical Computer, Ohmsha, published in 1985)
etc. are known.

Further, the recording medium 63 described above is rotated in a predetermined direction at a predetermined rotational speed by a rotation driving means (not shown). This rotation driving means and the image control section 53 described above are connected to a control section (not shown), and the rotational speed of the recording medium 63 is controlled based on a control command from the control section. That is, the rotational speed of the recording medium 63 is controlled in synchronization with the advancing speed of the image for each frame in the spatial modulator 51. Specifically, each time the image corresponding to one frame in the spatial modulator 51 changes, the recording medium 63 is rotated by a distance corresponding to the width of the slit 29a, that is, 1 mm.

Furthermore, since the recording medium 63 is formed of a photochromic material, erasing of the information regarding the hologram starts immediately after recording of the information regarding the hologram, that is, the recording of the interference fringes, but the photochromic material 13+ is inside the shell.
The erasing speed of information regarding the hologram is slow, and the information regarding the hologram is lost to the observer 6 due to the rotation of the recording medium 63.
By the time 5 is reached, sufficient information regarding this hologram has been retained. When the recording medium 63 is made of a photochromic material that erases information at a relatively slow speed, an erasing device 65 is provided upstream of the slit 29a to forcibly erase information regarding the hologram. Just configure it.

Conversely, if the recording medium 63 is constructed using a photochromic material that erases information about the hologram relatively quickly, the recording medium 63 is designed so that the information about the hologram reaches the observer 65 within the time before it is erased. If the rotation speed is adjusted, the observer 65 can reliably observe the three-dimensional reconstructed image.

Also, the rate at which information is erased is increased by applying heat to the hechromic material in the shell. Furthermore, it is known that the erasing speed of information can be increased by irradiating light of a specific wavelength especially with organic photochromic materials. (Literature,
Photosensitive glass materials, chemical review, inorganic photochemistry, No. 39.
(p. 207, Chemical Society of Japan, 1983) Therefore, the erasing device 65 can be constructed by utilizing such properties.

Specifically, it is preferable to incorporate a heat generating device into the erasing device 65 so as to heat the storage medium 63 to a predetermined temperature.

Further, it is preferable that the erasing device 65 is configured to incorporate a light irradiation means for irradiating the recording medium 63 with light of a specific wavelength.

Further, a white light source 41 for irradiating white light is arranged above the recording medium 63.

Next, the operation of the embodiment shown in FIG. 1 will be explained.

Images for each frame are sequentially supplied to the display panel of the spatial modulator 51 from the image control section 53.

Therefore, on the display panel of the spatial modulator 51, images for each frame, that is, consecutive images of the object in different viewing directions are sequentially displayed. The laser light transmitted through this display panel advances to the slit 29a via the projection lens 23, field lens 25, and cylindrical lens 27. Therefore, a projected image is obtained by transmitting the laser light through the display panel of the spatial modulator 51 at the Surin 1 29a. Further, the slit 29a is irradiated with a reference light 31a from a reference light source 31, and this reference light 31a and laser light interfere, and due to this interference, fine striped interference fringes are generated with the same size as the slit 29a. be done. A recording medium 63 formed of a photochromic material is rotating clockwise at a predetermined speed, and interference fringes generated in the slit 29a are sequentially recorded on the recording medium 63.

Next, reproduction of a three-dimensional image will be explained.

A white light source 41 is placed above the recording medium 63 that rotates at a predetermined rotational speed, and illuminates the recording medium 63 on which interference fringes are recorded from above. The installation location of this white light source 41 is not limited to above the recording medium 63, but may be placed at an appropriate position, for example, below the recording medium 63.
It may be configured to illuminate from below.

When the interference fringes recorded on the recording medium 63 reach the side of the observer 65, the interference fringes recorded on the recording medium 63 are illuminated by the white light source 41, and the observer 65
A rainbow-colored stereoscopic image 43 can be observed near the center of 3.

In the above-described embodiments, the recording medium 63 is constructed using a photochromic material, but the present invention is not limited thereto, and may be constructed using an appropriate re-recordable material. be able to. For example, if the recording medium 63 is made of thermoplastic, charging means for charging the entire recording medium 63 is installed upstream of the slit 29a, and the recording medium 63 is installed downstream of the slit 29a. It becomes necessary to provide a recharging means for recharging the entire battery. Furthermore, it is necessary to provide a developing means for generating irregularities based on information regarding the hologram recorded on the recording medium 63 downstream of this recharging means. Furthermore, if an erasing device 65 is installed upstream of the charging means, information regarding the hologram can be repeatedly recorded.

Furthermore, in the embodiment described above, the object light transmitted through the spatial modulator 51 and the reference light from the reference light source are configured to interfere and generate interference fringes from both lights. If the structure 1 is configured such that the image is imaged or generated in advance by the image carrier and recorded on the recording medium 63 directly or by enlarging or reducing it using an optical system, the hologram can be created without using Raded light. information can be easily recorded on a recording medium.

In addition, in the embodiment shown in FIG. 1, the display panel of the liquid crystal preview image receiver is configured to transmit laser light using a spatial modulator, so that continuous images of the object viewed from different directions can be displayed. It can be easily transmitted by telecommunication means.

[Effects of the Invention] As explained above, according to the present invention, since the recording medium for recording information about holograms is made of a material that can be rerecorded, it is possible to save time and effort related to complicated photographic processing such as development. The three-dimensional image can be repeatedly reproduced at the same time as information about the hologram is written.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a method for creating an original film, FIG. 3 is an explanatory diagram showing a conventional method for creating a hologram, and FIG. The figure is an explanatory diagram showing a method for reproducing the hologram shown in FIG. 3. L...Laser beam 31...Reference light source 63...Recording medium

Claims (1)

[Claims] A hologram is created by recording interference fringes obtained by interfering a signal wave obtained from successive images of an object in different observation directions with a reference wave unrelated to the image on a recording medium. A holographic stereogram for creating a holographic stereogram, characterized in that the recording medium is made of a re-recordable material.