JP2871684B2 - Method for producing color holographic stereogram - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a color holographic stereogram and a method for producing the same. [Prior Art] With the development of technology for obtaining coherent light such as a laser, holography technology has been gradually generalized. In the field of holography, a hologram in which object image information is recorded as interference fringes using coherent light is produced. When this hologram is irradiated with reproduction light,
The faithful three-dimensional reproduction of the object image can be performed by the diffraction effect of the interference fringes. Recently, a holographic stereogram technique has been developed in order to widen the viewing angle at which a hologram reconstructed image can be obtained. As the holographic stereogram, in addition to the laser beam reproduction type, a white light reproduction type has been developed, and in the latter case, it is called an integral hologram or a multiplex hologram finished as a cylindrical display. Are known. [Problems to be Solved by the Invention] In the conventional holographic stereogram described above, there is an advantage that the viewing angle can be widened, but the obtained reproduced image is of a single color if the viewpoint position is the same,
A reproduced image having the natural color of the object cannot be obtained. Therefore, even when the reproduced image is viewed, the sense of presence as if viewing a real object cannot be obtained. Therefore, an object of the present invention is to provide a color holographic stereogram capable of obtaining a natural color reproduction image of an object and a method for manufacturing the same. [Means for Solving the Problems] The present invention relates to a holographic stereogram in which a large number of unit regions on which hologram patterns are formed are continuously arranged, and the hologram patterns formed in each unit region are viewed from different angles. It is configured to reproduce a subject image, each unit area is composed of three small areas of first, second, and third, respectively, and three primary colors of first, second, and third that can be added and mixed with each other. The hologram pattern is reproduced by irradiating a reproduction light including the following from a predetermined direction, and for each micro area belonging to the same unit area, a direction in which the first micro area diffracts the first primary color;
The diffraction pattern is recorded such that the direction in which the second minute region diffracts the second primary color and the direction in which the third minute region diffracts the third primary color are substantially the same. is there. In order to perform such recording, the present invention produces a color holographic stereogram through the following steps. A first stage of creating n original images in which a subject is observed from different angles, and color-separating each of the n original images by three primary colors of first, second, and third, which can be additively mixed with each other, A second stage of obtaining first, second, and third color separation images for each of the original images; n pieces of first, second, and third minute regions on the photosensitive original plate, respectively; A third step of continuously defining a unit area of the first, a hologram pattern of a first color-separated image of one original image using a mask that exposes only a first minute area in the one unit area; A fourth step of exposing the photosensitive original plate at an average interference fringe interval, using a mask that exposes only a second minute area in the same one unit area, and a second color separation image of the same original image Of the hologram pattern at the second average interference fringe interval Fifth step of exposing on the original, using a mask that exposes only the third minute area in the same one unit area, and averaging the hologram pattern of the third color-separated image of the same one original with a third average The sixth step of exposing the photosensitive original at interference fringe intervals, the fourth, fifth, and sixth steps are performed by using color separation images of different original images for each of n unit areas. The seventh step is repeated. [Operation] In the color holographic stereogram according to the present invention, when the reproduction light is irradiated from a predetermined direction, each of the primary colors of the diffracted light from the three minute regions is three times in total.
The primary colors are emitted in almost the same direction. Therefore, from a specific viewpoint, the three primary colors from the three micro areas are added and mixed and observed, and a natural color reproduced image can be obtained. Further, in the method for producing a color holographic stereogram according to the present invention, for each of the first, second, and third minute regions, a color separation image of three primary colors of first, second, and third with respect to the same original image. A hologram pattern is formed. At this time, if the average interval of the interference fringes of the pattern recorded for each minute area is made different, the wavelength of the light diffracted from each minute area in substantially the same direction can be reduced by three times.
The wavelength of the primary color can be used, and the above-mentioned color holographic stereogram can be manufactured. EXAMPLES Hereinafter, the present invention will be described based on examples illustrating the drawings. Embodiment of Color Holographic Stereogram FIG. 1 is a principle diagram of a color holographic stereogram according to an embodiment of the present invention. In the stereogram 1, a large number of unit areas 2 (only four are shown in the figure for convenience) are continuously arranged. Each unit area 2
Are the first minute region 2R, the second minute region 2G, and the third minute region 2G, respectively.
Is composed of three minute regions 2B. If these minute regions are set to be sufficiently smaller than the resolution of the eyes, a unit region 2 combining three minute regions can be used.
Can be grasped as one pixel. A hologram pattern for each color component is recorded in each minute region, and the hologram recorded for each unit region 2 is different. That is, the subject images are obtained by viewing the subject from different angles, and have a holographic stereogram shape as a whole. Now, R (red), G (green), B
Assuming that a reproduction light 3 (for example, white light) including three primary colors (blue) that can be added and mixed together is irradiated, diffracted light is emitted from each minute region based on a hologram pattern formed respectively. . At this time, each minute region generates diffracted light for all three primary colors. For example, the minute region 2R does not necessarily generate only the diffracted light for the primary color R, but generates diffracted light for all three primary colors R, G, and B. From the principle of diffraction, the diffraction angle depends on the wavelength. Slightly different. However, the feature of the stereogram according to the present invention is that, for three minute regions belonging to the same unit region 2, the direction of the diffracted light 4R having the wavelength of the primary color R diffracted from the minute region 2R and the direction of the minute region 2G The point is that the direction of the diffracted light 4G having the wavelength of the primary color G to be diffracted and the direction of the diffracted light 4B having the wavelength of the primary color B diffracted from the minute area 2B are substantially the same. The directions of the diffracted light beams may include a direction error corresponding to the wavelength resolution of the eye, and therefore need not be completely the same. Therefore, at the viewpoint 5, as the hologram reproduced image from each unit area, the reproduced images of the three primary colors are obtained in an overlapping manner. In the hologram, even the shade information of the object image is reproduced. In this way, by superimposing the reproduced images of the three primary colors each having shading of each color component, a reproduced image of a natural color can be observed. As described above, the diffraction angle of the diffracted light when the same diffraction pattern is generally formed differs depending on the wavelength of the illumination light. Therefore, in order to equalize the diffraction angles of the diffracted lights with respect to the three primary colors, it is necessary to slightly change the diffraction pattern depending on each minute region. Since this diffraction pattern is formed as an interference fringe between the object light and the reference light when the hologram is formed, the average interval of the interference fringes may be changed. FIG. 2 shows a so-called integral hologram in which the color holographic stereogram 1 shown in FIG. 1 is made cylindrical. By illuminating with a white light source such as a light bulb 6, a reproduced image 7 of a natural color is obtained near the center of the cylinder. First Embodiment of a Method for Producing a Color Holographic Stereogram An embodiment of such a method for producing a color holographic stereogram will now be described with reference to the flowchart of FIG. First, in step S1, n original images obtained by observing a subject from different angles are created. For example, as shown in FIG. 4, the subject 8 may be placed on a turntable 9, and the subject 8 may be photographed by the video photographing camera 10 while rotating the subject 8 in the direction of the arrow in the figure. Turntable 9
If one frame is shot each time the camera rotates 360 ° / n, n color films obtained by observing the subject 8 from different angles by 360 ° / n can be obtained. The n color films serve as original images. Next, in step S2, each original image is separated into three color separation images. This is, for example, for each of the n color films obtained in step S1,
Color separation may be performed using red and yellow filters to create a color separation film that is color-separated into three primary colors of red, green and blue that can be added and mixed. A total of 3n color separation films will be created. Subsequently, in step S3, n unit areas are defined on the photosensitive master. For example, as shown in FIG. 1, a strip-shaped elongated unit area 2 may be defined. Further, the first minute region 4R and the second minute region 4
G, a third minute area 4B is defined. Next, in steps S4, S5, and S6, hologram exposure of a color separation image of one original image is performed in one unit area 2 defined in the previous step. That is, step S4
Then, hologram exposure using the red color separation film of one original image is performed on the minute region 2R in FIG. 1, and in step S5, hologram exposure using the green color separation film of the same original image is performed on the minute region 2G. In step S6, the minute area 2B
Next, hologram exposure using the same original blue color separation film is performed. At this time, the hologram patterns of the color separation films are recorded at different average interference fringe intervals. If the average interference fringe interval is set well, when reproducing the recorded hologram, the red wavelength light diffracted from the minute area 2R, the green wavelength light diffracted from the minute area 2G, and the diffracted light from the minute area 2B And the blue wavelength light can all be directed to the same direction. In this embodiment, the average interference fringe interval is changed by changing the irradiation angle of the reference light used for hologram recording for each color separation film. FIG. 5 is a diagram showing an embodiment of an optical system for recording such a hologram. The red color separation film 11R is irradiated with illumination light 12 to form an imaging lens 13, a condenser lens 1
4. The transmitted light 12 'of the film 11R is guided to the minute area 2R (shown by hatching) of the photosensitive master 16 via the cylindrical lens 15. An elongated slit 17a in front of the photosensitive master 16
The opened mask 17 is placed. Cylindrical lens 15
The light condensed in the form of a strip reaches the photosensitive original plate 16 through the slit 17a. In addition, the photosensitive original plate 16 is irradiated with reference light 18 through a beam expander 19, and interference fringes between the transmitted light 12 'and the reference light 18 are recorded in the minute area 2R. The above is the exposure step of step S4, but subsequently, instead of the film 11R, using the green and blue color separation films 11G and 11B, the minute area 2R
If the same exposure is performed on the minute regions 2G and 2B adjacent to the
The exposure steps of steps S5 and S6 are completed. FIG. 6 shows an example of a specific exposure method. Here, only one unit area composed of three minute areas 2R, 2G, and 2B is shown on the photosensitive original plate 6, but a large number of such unit areas are actually arranged continuously. FIG. 6 (a)
FIG. 2 is a view showing the basic principle of this exposure method. The transmitted light 12 ′ from the color separation film is vertically incident on the photosensitive master 16,
The reference light incident angle for each of RGB is θ _R ,
Exposure is performed in place of θ _G and θ _B. In order to perform such exposure, a mask 17 as shown in FIG. 6B is used. The mask 17 has an opening 17a for exposure equal to the width of the minute regions 2R, 2G, 2B. This mask 17
Is set at, for example, a position as shown in FIG. 6B, only the minute area 2R on the photosensitive original plate 16 can be exposed. Then, the mask 17 is set at this position, the reference light 18 is irradiated at an incident angle θ _R , and hologram exposure of the color separation film for the primary color R is performed. Subsequently, the mask 17 is moved to the position shown in FIG. 6 (c) so that only the minute area 2G can be exposed, the incident angle of the reference light 18 is set to θ _G , and the hologram exposure of the color separation film for the primary color G is performed. I do. Finally, the mask 17 is moved to the position shown in FIG. 6D so that only the minute area 2B can be exposed, and the reference light 18
The hologram exposure of the color separation film for the primary color _B is performed with the incident angle of θB as θB. The incident angle of the reference light is RGB 3
It is determined based on the wavelength of the primary color. In the above embodiment, the mask 17 is moved, but the photosensitive original plate 16 may be moved. Thus, the exposure for one unit area 2 is completed. Then, when the same is repeated for the n unit areas 2 (step S7), a color holographic stereogram 1 as shown in FIG. 1 is obtained. Note that, instead of repeating one procedure from steps S4 to S6 n times, first, step S4 is performed on n minute regions 2R,
Subsequently, step S5 may be performed on n minute regions 2G, and finally step S6 may be performed on n minute regions 2B. Second Embodiment of Manufacturing Method of Color Holographic Stereogram Next, another embodiment of the manufacturing method will be described. Step S1 is exactly the same as in the first embodiment, and n color films are obtained as original images. Subsequently, a color separation image is obtained in step S2. Instead of forming a color separation film as in the first embodiment, the color film created in step S1 is irradiated with light of a predetermined single wavelength, The color separation image is obtained from the transmitted light. FIG. 7 shows an optical system used in this embodiment. Here, three types of lasers 20R, 20G, and 20B having different oscillation wavelengths are provided, respectively, red, green, and
The blue single-wavelength coherent light 21R, 21G, 21B is output. These lights pass through the light amount adjustment filters 22R, 22G, and 22B, pass through the shutters 23R, 23G, and 23B, and pass through the wavelength selection mirror 2.
Reach 4R, 24G, 24B. The wavelength selection mirrors 24G and 24B
These mirrors reflect green and blue light, respectively, and transmit more light outside. Actually, only one of the shutters 23R, 23G, and 23B opens, and the coherent light 25 becomes one of the coherent lights 21R, 21G, and 21B by the shutter operation. This coherent light 25 is split by a half mirror 26, one of which is reflected by a mirror 27 and
18 and the other is reflected by mirrors 28, 29 and 30, passes through beam expander 31 and condenser lens 32, and
It becomes 12. The other components are the same as those of the optical system shown in FIG. The feature of this optical system is that the wavelengths of the illumination light 12 and the reference light 18 can be selected from three types of red, green, and blue by operating the shutters 23R, 23G, and 23B. The ability to select each wavelength has two advantages. First, a color separation image can be obtained without using a color separation film by selecting the wavelength of the illumination light 12. That is, in this embodiment, a color separation image can be obtained using the color film 11 obtained in step S1 as it is. For example, when the color film 11 is irradiated with red illumination light 12, the transmitted light 12 'contains a red separation image. The second point is that the average interference fringe interval for each color can be changed by selecting the wavelength of the reference light 18 without changing the irradiation angle of the reference light. If the wavelength of the reference light is different, the interval between the interference fringes will naturally be different without changing the irradiation angle. Therefore, there is no need to change the reference light irradiation angles θ _R , θ _G , and θ _B for each color as in the first embodiment. When this optical system is used, the exposure process (steps S4 to S6) for one unit area 2 is performed as follows. First, one color film 11 is prepared, only the shutter 23R is opened, and the hologram of the red component of the color film 11 is recorded in the minute area 2R using the red illumination light 12 and the reference light 18 (step S4). Subsequently, only the shutter 23G is opened, and the green component of the same color film 11 is recorded in the minute area 2G (Step S5). Further, only the shutter 23B is opened, and the coloring component of the same color film 11 is recorded in the minute area 2B. (Step S6). Thus, in this embodiment, 3
Although different types of lasers are required, the manufacturing process can be simplified as compared with the first embodiment. As described above, the present invention has been described with respect to some embodiments. However, the present invention is not limited to these embodiments, and various other embodiments can be implemented.
For example, the arrangement of the minute regions 2R, 2G, and 2B in each unit region 2 is not limited to the arrangement shown in FIG. 1, but may be repeatedly arranged in the vertical direction as shown in FIG. [Effects of the Invention] As described above, according to the present invention, a color holographic stereogram is manufactured by recording color separation images of three primary colors of a subject in separate micro areas, respectively. A color reproduction image can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a principle diagram of a color holographic stereogram according to an embodiment of the present invention, FIG. 2 is a perspective view of an integral hologram obtained by making the stereogram of FIG. 1 into a cylindrical shape, FIG. 3 is a flowchart showing steps of a method for producing a color holographic stereogram according to one embodiment of the present invention;
FIG. 4 is an explanatory view of the step S1 in FIG. 3, FIG. 5 is an explanatory view of an optical system for performing the steps S4 to S6 in FIG. 3, and FIG. 6 is a step S4 to S4 in FIG. FIG. 7 is a principle diagram of S6, FIG. 7 is an explanatory diagram of another optical system for performing the steps S4 to S6 of FIG. 3, and FIG. 8 is another embodiment of a color holographic stereogram according to the present invention. It is a front view. DESCRIPTION OF SYMBOLS 1 ... Color holographic stereogram, 2 ... Unit area, 2R, 2G, 2B ... Micro area, 3 ... Reproduction light, 4R, 4G, 4B ... Diffraction light, 5 ... Viewpoint, 6 ... Light bulb, 7 ... Reproduction image, 8 …subject,
Reference numeral 9: turntable, 10: video camera, 11: color film, 11R: red separation film, 12: illumination light, 12 ': transmitted light, 13: imaging lens, 14: condenser lens, 15: cylindrical lens , 16: Photosensitive original plate, 17: Mask, 17a: Slit, 18: Reference beam, 19: Beam expander, 20R, 20G,
20B… Laser, 21R, 21G, 21B… Coherent light, 22R, 22G,
22B: Light amount adjustment filter, 23R, 23G, 23B: Shutter, 24
R, 24G, 24B: wavelength selective mirror, 25: coherent light, 26
... half mirror, 27,28,29,30 ... mirror, 31 ... beam expander, 32 ... condenser lens.

Claims (1)

(57) [Claims] A first stage of creating n original images in which a subject is observed from different angles, and color separation of each of the n original images by first, second, and third primary colors capable of being additively mixed with each other; A second stage of obtaining first, second, and third color separation images for each of the original images; and n units of first, second, and third minute regions, respectively, on the photosensitive original plate A third step of continuously defining an area, and using a mask for exposing only the first minute area in one unit area, forming a hologram pattern of the first color separation image for one original image into the first A fourth step of forming an interference fringe between the reference light emitted at a first angle corresponding to the primary color and the first color separation image by recording the interference fringe on the photosensitive original plate; Using a mask for exposing only the second minute area in The hologram pattern of the second color separation image is irradiated with a second angle different from the angle corresponding to the first primary color and at a second angle corresponding to the second primary color, and is composed of light having the same wavelength as the reference light. A fifth step of forming interference fringes between the reference light and the second color separation image by recording the interference fringes on the photosensitive master, and using a mask that exposes only a third minute area in the one unit area. The hologram pattern of the third color-separated image of the one original image at an angle corresponding to the third primary color, which is different from an angle corresponding to the first primary color and an angle corresponding to the second primary color. A sixth step of forming by irradiating an interference fringe between the reference light composed of light having the same wavelength as the reference light and the third color-separated image on the photosensitive original plate; The fifth and sixth steps are performed for each of the n unit areas. And a seventh step of repeating using color separation images of different original images, respectively. 2. 2. The color holographic stereogram according to claim 1, wherein in the first step, the subject is photographed from a predetermined position while rotating the subject on a turntable to create n original images. Manufacturing method. 3. In a first step, an original image is created by a color film, and in a second step, images of three color separation films obtained from the color film are used as respective color separation images. 3. The method for producing a color holographic stereogram according to claim 1 or 2. 4. 4. The method according to claim 1, wherein red is used as the first primary color, green is used as the second primary color, and blue is used as the third primary color.
The method for producing a color holographic stereogram according to any one of the above.