JP4962246B2 - Computer generated hologram, computer generated hologram device, computer generated hologram method, and printed information - Google Patents

Description

  The present invention relates to a computer generated hologram having a high anti-counterfeit effect and its production.

  In recent years, holograms that display images of three-dimensional objects have been applied to prevent forgery of printed information. For example, it is used for IC cards and banknotes.

  As a method for recording the specific information on the hologram and reading the information, there is a method using a Fourier transform type hologram or the like (for example, see Non-Patent Document 1). When a predetermined light is incident on the Fourier transform hologram, information recorded on the hologram is reproduced by the first-order diffracted light.

  As information recorded on the hologram, generally, interference fringe data due to interference between object light from a real target (subject) and reference light is recorded.

On the other hand, a hologram can be produced by modeling a three-dimensional object on a computer (computer) even if the object does not actually exist. Such a hologram is called a “computer generated hologram (CGH)”. When producing a computer generated hologram, image data of a three-dimensional object corresponding to an object is defined on a computer (computer), and light wavefront information is calculated. Then, light wavefront information is recorded on a substrate such as a photosensitive film (see, for example, Patent Document 1).
Japanese Patent No. 3951554 P. Hari Haran, “Principles of Holography”, Optronics Inc.

  In the above-described computer generated hologram, it is possible to display a stereoscopic image of an object that does not exist.

  However, even if a computer generated hologram is produced by modeling a three-dimensional object having a simple configuration that can produce a real object, the anti-counterfeit effect may not be sufficient. This is because a three-dimensional object that can produce a real object can be produced by a general hologram technique in which a real object is photographed by laser two-beam interferometry.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a computer generated hologram having a high effect of preventing forgery.

  The present invention takes the following means in order to solve the above problems.

  The invention corresponding to claim 1 is a computer generated hologram manufacturing method for generating a computer generated hologram by recording interference fringe data calculated by a computer on a substrate, and indicates a position where the interference fringe data is recorded on the substrate. The interference fringe recording point writing step for writing the interference fringe recording points into the interference fringe recording point storage means, the image data including the shape data and pattern data of the three-dimensional object and the observation angle data are written in correspondence with each other in the image data storage means. A step, an input step of inputting pattern data that can be pasted on the image data of the three-dimensional object together with observation angle data, and pattern data of the three-dimensional object corresponding to the observation angle data input in the input step, A conversion step of converting the pattern data input in the input step; and the pattern data is converted by the conversion step. A calculation step of calculating interference fringe data for each of the interference fringe recording points from the converted image data of the three-dimensional object, and an interference fringe recording step of recording the interference fringe data calculated by the calculation step on the substrate; Is a computer-generated hologram manufacturing method.

  According to a second aspect of the present invention, in the computer generated hologram production method according to the first aspect, the interference fringe recording point writing step includes the shape data of the interference fringe recording surface of the substrate on which the interference fringe data is recorded, and In response to the input of position data and the input of shape data and position data of the interference fringe recording surface, a plurality of horizontal slits are set in the vertical direction of the interference fringe recording surface, and the inside of the slits is horizontally oriented. And a step of setting a plurality of interference fringe recording points by dividing into two.

  According to a third aspect of the present invention, in the computer generated hologram manufacturing method corresponding to the first or second aspect, the interference fringe recording step changes the light transmittance of the transparent material substrate according to the position. A computer-generated hologram manufacturing method for recording the interference fringe data.

  According to a fourth aspect of the present invention, in the computer generated hologram production method corresponding to any one of the first to third aspects, the interference fringe recording step includes changing the concavo-convex shape of the substrate surface to change the interference. This is a computer generated hologram manufacturing method for recording fringe data.

  The invention corresponding to claim 5 is a computer generated hologram produced by the method of producing a computer generated hologram corresponding to any one of claims 1 to 4, wherein the three-dimensional object has a parallax only in a horizontal direction. This is a computer generated hologram to which texture mapping data or bump mapping data is applied only at a specific observation angle so that the color and texture of the surface of the lens changes.

  The invention corresponding to claim 6 is a computer generated hologram producing apparatus for producing a computer generated hologram by recording the interference fringe data calculated by the computer on the substrate, and indicates a position for recording the interference fringe data on the substrate. Interference fringe recording point storage means for storing interference fringe recording points, image data storage means for storing image data including shape data and pattern data of the three-dimensional object and observation angle data in association with each other, Input means for inputting pattern data that can be pasted to image data together with observation angle data, and pattern data of the three-dimensional object corresponding to the observation angle data input by the input means is input by the input means An interference fringe for each interference fringe recording point from the pattern data converting means for converting the pattern data into image data of a three-dimensional object into which the pattern data has been converted; And interference fringe data calculating means for calculating over data, a computer generated hologram manufacturing apparatus provided with the interference fringes recording means for recording the interference pattern data calculated by the interference fringe data calculating means on the substrate.

  The invention corresponding to claim 7 is a computer generated hologram that displays a three-dimensional object with parallax only in the horizontal direction, and the image of the three-dimensional object has a surface color and texture depending on the angle to be observed. It is a computer generated hologram to which texture mapping data or bump mapping data is applied only in a specific observation angle range so as to change.

  The invention corresponding to claim 8 is the computer generated hologram corresponding to claim 7, wherein the image of the three-dimensional object includes a plurality of texture mapping data such that the color and texture of the surface changes according to the angle to be observed. Or it is a computer generated hologram to which bump mapping data is applied.

  The invention corresponding to claim 9 is the computer generated hologram corresponding to claim 7 or claim 8 in which images of characters, symbols, pictures, etc. are represented on a three-dimensional object by texture mapping.

  The invention corresponding to claim 10 is the computer generated hologram corresponding to any one of claims 7 to 9, wherein the specific color and texture are three-dimensional only in a part of a narrow range within a preset viewing zone. It is a computer generated hologram in which an image of an object can be observed.

  The invention corresponding to claim 11 is the computer generated hologram corresponding to claim 10, wherein the narrow range includes the center of the viewing zone and is a range of 1/5 or less of the entire viewing zone.

  The invention corresponding to claim 12 is the computer generated hologram corresponding to claim 10, wherein the narrow range includes the outermost side of the viewing zone and is a range of 1/5 or less of the entire viewing zone.

  The invention corresponding to claim 13 is an information printed matter in which the computer generated hologram corresponding to any one of claims 7 to 12 is provided in at least a part of the surface region of the printed matter base material.

<Action>
Therefore, the present invention has the following effects by taking the above-described means.

  The invention corresponding to claims 1 and 6 reads out the pattern data of the three-dimensional object corresponding to the observation angle data input by the input means from the image data storage means, and the pattern data of the three-dimensional object is input by the input means. Interference fringe data is calculated for each interference fringe recording point from the image data of the three-dimensional object into which the pattern data is transformed, and the interference fringe data is recorded on the substrate, so only at a specific observation angle. The readable information is displayed, and a computer generated hologram having a high forgery prevention effect can be produced.

  The invention corresponding to claim 2 inputs the shape data and position data of the interference fringe recording surface of the substrate on which the interference fringe data is recorded, in addition to the operation corresponding to claim 1, and the shape data of the interference fringe recording surface And according to the input of position data, a plurality of slits that are horizontally long are set in the vertical direction of the interference fringe recording surface, and a plurality of interference fringe recording points are set by dividing the inside of the slit in the horizontal direction. A computer generated hologram having parallax only in the horizontal direction is produced, and the amount of calculation can be reduced.

  The invention corresponding to claim 3 records the interference fringe data by changing the light transmittance in the substrate of the transparent material according to the position in addition to the action corresponding to claims 1 and 2, and so-called transmission. Type holograms can be produced.

  The invention corresponding to claim 4 records the interference fringe data by changing the concavo-convex shape of the substrate surface in addition to the actions corresponding to claims 1 to 3, so that a computer generated hologram can be obtained by using a metal stamper or the like. Can be easily mass-produced and replicated.

  The inventions corresponding to claims 5 and 7 to 9 have the parallax only in the horizontal direction and the texture mapping data or the bump mapping data only at a specific observation angle so that the color and texture of the surface of the three-dimensional object change. Since it is applied, information that can be read only at a specific observation angle is displayed, and a computer generated hologram having a high forgery prevention effect can be provided.

In the invention corresponding to claim 10, in addition to the actions corresponding to claims 7 to 9, the image of the three-dimensional object can be observed only in a part of a narrow range within a predetermined viewing area with a specific color and texture. Therefore, it is possible to provide a computer hologram having a high effect of preventing forgery. In addition to the operation corresponding to claim 10, the narrow range includes the center of the viewing zone, and the entire viewing zone. Therefore, it is possible to provide a computer generated hologram that is difficult to recognize the presence of specific information unless it is known in advance or carefully observed.

  In the invention corresponding to claim 12, in addition to the action corresponding to claim 10, since the narrow range includes the outermost side of the viewing zone and is a range of 1/5 or less of the entire viewing zone, it is not normally observed. Information can be read only at such an angle, and a computer generated hologram having a high forgery prevention effect can be provided.

  The invention corresponding to claim 13 has a high forgery prevention effect because the computer generated hologram corresponding to any one of claims 7 to 12 is provided in at least a part of the surface area of the printed material base. An information printed matter can be provided.

  According to the present invention, it is possible to provide a computer generated hologram having a high anti-counterfeit effect, a manufacturing method thereof, and the like.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
(Configuration of computer generated hologram device)
FIG. 1 is a schematic diagram showing the configuration of a computer generated hologram production apparatus 10 according to the first embodiment of the present invention.

  The computer generated hologram production apparatus 10 includes an interference fringe recording point storage unit 11, an interference fringe recording point setting unit 12, an image data storage unit 13, a pattern data storage unit 14, an input unit 15, an image data selection unit 16, and a pattern data conversion unit 17. An interference fringe data calculation unit 18 and an interference fringe recording device 19 are provided. The interference fringe recording point recording unit 11 to the interference fringe data calculation unit 18 other than the interference fringe recording device 19 can be realized by a combination of a hardware configuration and a software configuration. Specifically, each function is realized by installing in a computer a computer generated hologram production program obtained in advance from a computer-readable storage medium or network.

  The interference fringe recording point storage unit 11 is a memory for storing “interference fringe recording point data” on the substrate 5 on which interference fringe data is recorded. When producing the computer generated hologram, as shown in FIG. 2, position data of the light source LS, position data of the three-dimensional object O, position data and shape data of the interference fringe recording surface S are set. Next, as shown in FIG. 3, interference fringe data on the interference fringe recording surface S of the reference light RL from the light source LS and the object light OL from the three-dimensional object O is calculated. Therefore, the interference fringe recording point storage unit 11 stores the position where the interference fringe data on the interference fringe recording surface S is calculated as interference fringe recording point data.

  The interference fringe recording point setting unit 12 sets interference fringe recording point data and writes it in the interference fringe recording point storage unit 11. Specifically, when the position data and shape data of the interference fringe recording surface S are input via the input unit 15 described later, the interference fringe recording point setting unit 12 performs the interference fringe recording as shown in FIG. A plurality of long slits D are set in the horizontal direction (x direction) along the vertical direction of the surface S. Then, the interference fringe recording point setting unit 12 sets a plurality of interference fringe recording points P by vertically dividing the inside of the slit D in the horizontal direction (x direction), and sets the interference fringe recording point data as interference fringes. Write to the recording point storage unit 11. In FIG. 4, when the interference fringe data of the object light OL and the reference light RL is recorded at each interference fringe recording point P and the reproduction light PL is incident, the light represented by the wavefront W is observed by the observer E. And the image G1 is observed.

  The image data storage unit 13 is a memory that stores image data including shape data and pattern data of a three-dimensional object and observation angle data in association with each other. For example, as shown in FIG. 5, image data of a three-dimensional object is stored for each image name in association with observation angle data. When the positional relationship among the light source LS, the three-dimensional object O, and the interference fringe recording surface S is as shown in FIG. 3, an image within an observation angle range of 40 ° is observed, and image data is stored. The unit 13 stores image data corresponding to observation angle data from −20 ° to 20 °. Further, the image data storage unit 13 may store information on a three-dimensional object other than image data for each image name.

  The image data of the three-dimensional object is generated by means such as computer graphics or CAD. The modeling method of the object to be displayed by the computer hologram includes the method of expressing the curved surface of the object using free curves such as NURBS curves, spline curves, and Bezier curves, and polygons such as triangles and rectangles called polygons. There is a method of approximating a curved surface as a set of planes. As described above, since there are a plurality of methods for defining the shape of the three-dimensional object, the data stored in the image data storage unit 13 is not only image data, but also forms of equations indicating curves and curved surfaces, polygons, and the like. It can also take the form of vertex data. In addition, texture mapping data and bump mapping data are applied to express the texture of a three-dimensional object.

  The pattern data storage unit 14 is a memory that stores pattern data that can be pasted on the image data of the three-dimensional object O. Specifically, as shown in FIG. 6, the pattern data storage unit 14 stores a plurality of texture mapping data and bump mapping data for each pattern identification number.

  “Texture mapping” is a technique in which two-dimensional pattern data for determining color and texture defined separately from image data of a three-dimensional object is pasted on the object surface. By applying texture mapping to the surface of the shape data of the three-dimensional object, it is possible to give reality to the image. For example, as shown in FIG. 7, in the image data G2 of a sphere three-dimensional object having the same color on the entire surface, although the luminance changes according to the incident angle of the illumination light, the same color and texture can be obtained even if the observation angle is changed. Perceived and lacks three-dimensionality. In contrast, when a texture mapping pattern of, for example, a wood grain pattern is applied to the shape of the sphere as shown in FIG. 8, the wood grain pattern changes continuously according to the change in the observation angle. For this reason, a sense of depth due to peeping is increased, and a three-dimensional effect can be felt with respect to the spherical image data G3. In addition to metal light selection and tree rings, images such as Wenyu, numbers, symbols, designs, etc. can be used as textures that can be mapped. By mapping these textures, three-dimensional objects can be mapped. The image is perceived as sticking on the surface.

  “Bump mapping” is an expression technique in which the light reflection direction and the amount of light on the surface of a three-dimensional object are arbitrarily changed, and the surface is perceived as if there are irregularities. For example, as shown in FIG. 9, a three-dimensional effect can be obtained by giving a pattern of bump mapping to the image data G4 of a sphere of a three-dimensional object to give the surface an uneven feeling. Bump mapping can be easily achieved compared to modeling complex three-dimensional objects with irregularities. Therefore, the calculation load is small and it is effective as one method for defining the texture of a three-dimensional object.

  The input unit 15 is configured by a general mouse, keyboard, or the like, and inputs or selects various data. For example, shape data and position data of the interference fringe recording surface S of the substrate 5 on which interference fringe data is recorded are input via the input unit 15. Also, the image name displayed on the monitor is selected via the input unit 15. The pattern identification number is input via the input unit 15 together with the observation angle. Instead of inputting the pattern identification number, pattern data may be directly input from an external storage device such as a hard disk or an external information input unit such as a scanner or a camera.

  The image data selection unit 16 selects image data. When an image name is input via the input unit 15, the image data of the three-dimensional object O corresponding to the image name is received from the image data storage unit 13. It has a reading function. The image data read by the image data selection unit 16 is sent to the pattern data conversion unit 17.

  The pattern data conversion unit 17 converts the pattern data of the three-dimensional object corresponding to the observation angle data input by the input unit 15 into the pattern data input by the input unit 15. Thereby, in the three-dimensional hologram image, an image different from that observed from other angles is displayed only when observed from a specific angle.

  The interference fringe data calculator 18 calculates interference fringe data for each interference fringe recording point from the image data of the three-dimensional object whose pattern data has been converted by the pattern data converter 17. Specifically, the interference fringe data calculation unit 18 determines a complex amplitude distribution of the object light OL reaching the interference fringe recording point P from the three-dimensional object O based on the preset position data of the light source LS, Interference fringe data is calculated based on the complex amplitude distribution.

  The calculation of interference fringe data will be supplemented with reference to FIG. FIG. 10 is a plan view showing a state of object light that reaches an interference fringe recording point on a computer generated hologram from an object point arranged on a three-dimensional object. In the interference fringe recording point P1 located on the left side of the computer generated hologram shown in FIG. 10, the object light from the object points Q1 to Q5 arranged at equal intervals d in the x-axis direction along the surface of the three-dimensional object. Then, the amplitude intensity of the light at the interference fringe recording point P1 due to the interference with the reference light incident from a separately defined direction is calculated. Similarly, the amplitude intensity due to the interference between the object light from the object points Q1 to Q5 and the reference light is also calculated at the interference fringe recording point P2 located on the right side of the computer generated hologram. By performing such calculation at all interference fringe recording points, an interference fringe pattern as shown in FIG. 11 can be obtained by changing the amplitude intensity. In FIG. 10, for the sake of simplification, the numbers of object points and interference fringe recording points are shown in a limited manner, but there are actually many of them. Further, if the number of object points on the three-dimensional object and the number of interference fringe recording points (arrangement density) are increased, it becomes possible to produce a computer generated hologram with little missing information on the shape and texture of the object.

  By calculating the interference fringe data, the image data G of the three-dimensional object can be observed on the back side of the computer generated hologram as viewed from the observer E, or can be observed on the near side. Further, the incident direction of the reproduction light PL is not limited to the direction shown in FIG. 8 and can be determined by the producer when producing the computer generated hologram according to the illumination direction at the time of observation determined in advance.

  In the present embodiment, the interference fringe data storage unit 18 calculates the interference fringe data so as to have a parallax only in the horizontal direction. Thereby, the amount of calculation can be reduced. In general, if only the parallax in the horizontal direction can be reproduced, it is possible to display an image that produces a sufficient stereoscopic effect due to the binocular parallax.

  The interference fringe recording unit 19 is configured by a device having a high resolution drawing capability such as an electron beam drawing device, and records the interference fringe data calculated by the interference fringe data calculation unit 18 on the substrate 5. Specifically, the interference fringe recording unit 19 optically reduces and records the interference fringe grayscale image produced by a method of directly drawing the uneven structure of the interference fringe or a low-resolution image output device using a lens or the like. Interference fringe data is recorded on the substrate 5 by a method such as

  The interference fringe recording unit 19 records the interference fringe data on the substrate 5 in one or both of the density distribution and the phase modulation amount distribution. Here, the method of recording interference fringe data in the form of “density distribution” means that an interference fringe grayscale image produced by a low-resolution image output device is optically reduced using a lens or the like, In this method, interference fringe data is recorded on the substrate 5 to be formed. That is, by changing the concentration of the translucent material formed on the transparent material according to the position, the light transmittance or reflectance is changed, and a hologram image is displayed. The form of “phase modulation amount distribution” is a method of recording interference fringe data by forming fine irregularities on the substrate surface corresponding to the phase modulation amount or changing the refractive index. . In the case of mass-production duplication of computer generated holograms, it is more practical to adopt the form of phase modulation amount distribution that duplicates and transfers the uneven structure of interference fringes than the form of density distribution that reduces and records gray images.

(Operation of computer generated hologram)
Next, the operation of the hologram manufacturing apparatus 10 according to the present embodiment will be described with reference to the flowchart of FIG.

  First, position data indicating the positional relationship among the light source LS, the three-dimensional object O, and the interference fringe recording surface S is input via the input unit 15 (step S1). Further, the shape data of the interference fringe recording surface S is input (step S2).

  Subsequently, the interference fringe recording point setting unit 12 calculates an interference fringe recording point P indicating a position where the interference fringe data is recorded on the interference fringe recording surface S, and writes it in the interference fringe recording point storage unit 11 (step S3). The interference fringe recording point setting unit 12 sets a plurality of long slits D in the horizontal direction along the vertical direction on each interference fringe recording surface S on the substrate 5, and divides each slit D in the horizontal direction. Thus, the interference fringe recording point P is calculated.

  Subsequently, the image data G of the three-dimensional object O generated by means such as CAD is written in the image data storage unit 13 (step S4). Here, image data G including shape data and pattern data of a three-dimensional object is stored in the image data storage unit 13 together with observation angle data.

  Next, pattern identification information and observation angle data are input by operating the input unit 15 (step S5). When the pattern identification information is input, texture mapping data or bump mapping data stored in the pattern data storage unit 14 is selected by the pattern data conversion unit 17. Then, the pattern data conversion unit 17 converts the pattern data of the three-dimensional object corresponding to the input observation angle data into the selected texture mapping data (step S6).

  Subsequently, the object light reaching the interference fringe recording point from the three-dimensional object based on the preset position data of the light source from the image data of the three-dimensional object obtained by converting the pattern data by the interference fringe data calculation unit 18 And a complex amplitude distribution based on the reference light. Then, interference fringe data is calculated based on this complex amplitude distribution (step S7). At this time, depending on the incident angle of the object light, the texture mapping data or the bump mapping data may not be referred to. In this case, the texture is determined by using the initial value of the texture of the three-dimensional object.

  Then, the interference fringe data is recorded on the substrate 5 by the interference fringe recording unit 19 (step S8). Specifically, interference fringe data is recorded on the substrate 5 in the form of density distribution and / or phase modulation amount distribution by a fine processing apparatus such as an electron beam drawing apparatus, and a computer generated hologram having parallax only in the horizontal direction is produced. Is done.

(Operational effect of computer generated hologram)
As described above, according to the computer generated hologram production apparatus 10 according to the present embodiment, the pattern data of the three-dimensional object corresponding to the observation angle data input by the input unit 15 is read from the image data storage unit 13. The pattern data of the three-dimensional object is converted into the pattern data input by the input unit 15, the interference fringe data for each interference fringe recording point is calculated from the image data of the three-dimensional object obtained by converting the pattern data, and the interference fringe data is converted into the substrate. 5, information that can be read only at a specific observation angle is displayed, and a computer generated hologram having a high forgery prevention effect can be produced.

  Further, according to the computer generated hologram production apparatus 10 according to the present embodiment, a computer generated hologram having different colors and textures on the surface of a three-dimensional object can be produced according to the observation angle, so that a hologram produced using an actual subject. Thus, it is possible to display a three-dimensional object that cannot be expressed. In addition, a computer generated hologram having an improved eye catching effect can be produced by changing the pattern on the surface of the three-dimensional object stepwise according to the observation angle.

  Furthermore, according to the computer generated hologram production apparatus 10 according to the present embodiment, it is possible to produce a computer generated hologram in which character information visible only in a specific viewing zone is displayed on the surface. If a rule is provided in advance in the viewing area in which the character information is visible or the character information to be displayed, the authenticity of the computer generated hologram can be determined. Therefore, by forming a computer generated hologram that displays a pattern or the like that is visible only in such a specific viewing area on the information printed material, it can be used for authenticity determination of the information printed material.

  The computer generated hologram 10 according to the present embodiment can produce a computer generated hologram that displays a three-dimensional object modeled using computer graphics or three-dimensional CAD. Unlike that, it is possible to display what does not actually exist. For this reason, the information printed matter on which the computer generated hologram is attached is more difficult to counterfeit than the information printed matter produced by a general printing technique.

  Supplementally, in recent years, holograms for displaying three-dimensional objects and computer generated holograms have been used for various information prints, and three-dimensional objects by computer graphics can be viewed in various scenes such as movies and TV. Be able to. For this reason, it has become difficult to obtain a sufficient eye-catching effect by simply using image data of a three-dimensional object as a target for a computer generated hologram. On the other hand, in the computer generated hologram production apparatus according to the present embodiment, a computer generated hologram to which texture mapping data or the like different from other regions can be produced only in a specific viewing area can obtain a sufficient eye catching effect. it can.

  In the case of duplicating a computer generated hologram, a metal stamper is produced by a method such as electroforming from an original plate of a display body on which an uneven structure of interference fringes is formed. Using this metal stamper as a matrix, a thermoplastic resin or a photocurable resin is applied onto a transparent base material made of polycarbonate, polyester, or the like, and the metal stamper is brought into close contact therewith. Then, after applying heat and light to cure the resin, the computer generated hologram is duplicated by peeling the resin from the metal stamper.

  When the replicated computer generated hologram is transparent, a light reflecting layer is provided on the surface by a method such as vapor deposition of a metal or dielectric book film layer in vacuum. If a computer generated hologram with such a light reflecting layer is formed in the form of a transfer foil, a sticker, etc., and pasted on a base material such as paper or plastic film via an adhesive layer or an adhesive layer, it has a forgery prevention function. It becomes possible to produce printed information such as securities and cards.

  Further, in the computer generated hologram production apparatus 10 according to the present embodiment, by using texture mapping or pump mapping as pattern data, the color and texture of the surface of the three-dimensional object are changed, and a complex image such as a character or a pattern is displayed. Can also be realized. Therefore, although the surface shape itself is not changed, an object having a higher expressive power and a larger amount of information can be displayed by a computer generated hologram without significantly increasing a calculation load.

  Note that the hologram manufacturing apparatus 10 according to the present embodiment inputs shape data and position data of the interference fringe recording surface S of the substrate 5 on which interference fringe data is recorded, and shape data and position data of the interference fringe recording surface S. Since a plurality of slits D that are long in the horizontal direction are set in the vertical direction of the interference fringe recording surface S and the inside of the slit D is divided in the horizontal direction, a plurality of interference fringe recording points P are set. Thus, a computer generated hologram having parallax only in the horizontal direction is produced, and the amount of calculation can be reduced.

(Example)
Next, a computer generated hologram in which texture mapping or bump mapping data applied to a three-dimensional object is changed only at a specific observation angle will be described.

  Changing the texture mapping or bump mapping data applied to the three-dimensional object only at a specific observation angle is performed in advance among a plurality of object lights reaching the interference fringe recording surface S from the three-dimensional object O. This corresponds to the fact that only the object light that reaches the interference fringe recording surface S at the set arbitrary angle is determined from color and texture data different from the others.

  For example, an interference fringe pattern can be obtained according to the rules shown in FIG. 13 and FIG. 14 in order to obtain an effect in which a three-dimensional object O is subjected to wood grain texture mapping only when a computer generated hologram is observed almost from the front. May be generated. In FIG. 13, the three-dimensional object O is subjected to wood grain texture mapping.

  More specifically, an object that enters the interference fringe recording points P4, P5, and P6 located at the left, right, and center of the computer generated hologram almost perpendicularly from the object points Q5, Q7, and Q9 on the three-dimensional object. The complex amplitude distribution of the lights OL11 to OL13 is determined based on the color data and the texture data by the texture mapping of the wood grain pattern. On the other hand, as shown in FIG. 14, when the object light is incident on the computer generated hologram from an oblique direction, the complex amplitude distribution of the object light is determined without using the color data and the texture data by texture mapping.

  That is, in the computer generated hologram shown in FIGS. 13 and 14, the color data and the texture data of the three-dimensional object O from which the complex amplitude distribution of the object light is calculated according to the incident angle are selected, and the interference fringe pattern Has been derived. Therefore, a wood grain pattern can be observed on a three-dimensional object when observed from the front, and a wood grain pattern can be prevented from being observed when observed from other angles. In FIG. 13 and FIG. 14, in order to simplify the explanation, there are a small number of line segments and interference fringe recording points indicating the object point and the object light far from the object point. Omitted.

  FIG. 15 is a schematic diagram showing an example of a computer generated hologram to which different texture mapping or bump mapping is applied according to the incident angle of object light.

  As shown in FIGS. 16, 17, and 18, by applying different texture mapping or bump mapping according to the incident angle of the object light reaching the computer generated hologram, different colors and textures according to the observation angle Can be displayed.

  Here, in the production of one computer generated hologram, as shown in FIG. 16, for the object light incident on the computer generated hologram from the right direction, a wood grain texture is applied as a three-dimensional object pattern, and as shown in FIG. For the object light incident from the vertical direction, the texture with the letter “TOP” is applied, and for the object light incident from the left direction as shown in FIG. Interference fringe data is obtained by calculating the complex amplitude of the light due to interference with the reference light.

  Then, when the computer generated hologram is observed from various angles under appropriate illumination light, as shown in FIG. 15, the observer E1 located on the left side in the viewing zone has a grain pattern texture. An image G8 is observed, and a texture image G7 on which Wenwoo “TOP” is written is observed by an observer E2 located in the center, and an image G9 of a large stone pattern texture is observed by an observer E3 located on the right side. Is observed.

  Here, by providing information that can be observed only at a specific angle, such as the character “TOP” in FIG. 15, on a three-dimensional object, a special visual recognition that cannot be realized simply by recording a normal three-dimensional object. An effect can be given and an eye catching effect can be improved.

  Further, as shown in FIG. 15, by incorporating characters, symbols, patterns, etc. that can be read only at a specific observation angle into the image data of a three-dimensional object, it is possible to determine the authenticity of a computer generated hologram, thereby preventing forgery. The improvement of the effect can also be expected.

  In addition, computer holograms that display information that can be read only at a specific viewing angle, such as securities such as gift certificates and checks, cards such as credit cards, cash cards, ID cards, passports and licenses, etc. By sticking the information printed matter such as certificates on a paper base material or a plastic base material in the form of a transfer foil or a sticker, the forgery prevention effect of the information printed matter can be improved. As an example of the information printed matter, there is an IC card with a computer hologram attached as shown in FIG. The IC card 60 is partially provided with a computer generated hologram 50 so that an observer can observe an image of a three-dimensional object.

  In addition, when providing a texture that can be read only at a specific angle in anticipation of the information concealment effect, the interference pattern data of the computer generated hologram is calculated so that specific information can be grasped only within a narrow range within the viewing zone. It is more desirable to do. This is because if the specific texture data can be observed over a wide range, the information concealment effect is low and its presence is easily perceived.

  Specifically, it is desirable that the narrow range in which a specific texture can be grasped is a range of approximately 1/5 or less of the entire viewing zone where a three-dimensional object is observed. If the range is about 1/5, the area where the concealment information can be seen is sufficiently limited, and it is difficult to recognize the presence of specific information unless the existence is known beforehand or carefully observed. .

  FIG. 20 is a schematic diagram of a computer generated hologram to which texture mapping is applied so that the sentence “TOP” can be read only in a narrow area R2 including the center line C of the viewing area R1. In such a computer generated hologram, the character “TOP” cannot be read unless the observer E2 observes almost from the front, and cannot be observed by the observers E1 and E3 at other positions. Furthermore, as shown in FIG. 21, when the narrow range R2 is located at the outermost side of the viewing zone R1, the character “TOP” can be read only at a steep angle that is not normally observed. The effect can be improved.

  In general, a computer generated hologram for displaying a three-dimensional image is used for the purpose of preventing forgery of printed information, and is often produced in the form of a sticker or sticker modeled on animals or characters. In the case of such a form, the width of the computer generated hologram is about 1 to 10 cm. The viewing zone is often set to 40 ° or less. If a viewing area larger than that is provided, the stereoscopic image becomes difficult to see as the distance from the center of the viewing area increases, or the depth of the stereoscopic image cannot be sufficiently obtained. When the viewing zone is 40 °, about 8 °, which is 1/5 of the viewing zone, is desirable as the narrow range setting.

<Others>
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

It is a schematic diagram which shows the structure of the computer generated hologram production apparatus 10 which concerns on the 1st Embodiment of this invention. It is a schematic diagram for demonstrating the production method of a computer generated hologram. It is a schematic diagram for demonstrating the production method of a computer generated hologram. It is a schematic diagram which shows the structure of a computer generated hologram. 3 is a schematic diagram illustrating a configuration of an image data storage unit 13. FIG. 3 is a schematic diagram showing a configuration of a pattern data storage unit 14. FIG. It is a schematic diagram which shows an example of the computer generated hologram without a mapping process. It is a schematic diagram which shows an example of the computer generated hologram to which the texture mapping is applied. It is a schematic diagram which shows the concept of the computer generated hologram to which bump mapping was applied. It is a figure for demonstrating the calculation process of the interference fringe data calculation part. It is a schematic diagram which shows the structure of the interference fringe by interference fringe data. The operation of the hologram manufacturing apparatus 10 according to the embodiment will be described with reference to the flowchart of FIG. It is a figure for demonstrating the calculation process when a computer generated hologram is observed from substantially the front. It is a figure for demonstrating the calculation process when a computer generated hologram is observed from diagonally. It is a schematic diagram which shows an example of the computer generated hologram which concerns on the same embodiment. It is a schematic diagram which shows an example of the computer generated hologram observed with a different observation angle. It is a schematic diagram which shows an example of the computer generated hologram observed with a different observation angle. It is a schematic diagram which shows an example of the computer generated hologram observed with a different observation angle. It is a schematic diagram which shows an example of the information printed matter with which the computer generated hologram which concerns on the embodiment was affixed. It is a schematic diagram which shows an example of the computer hologram which can read concealment information only in the narrow area | region R2 containing the center line C of visual field R1. It is a schematic diagram which shows an example of the computer hologram which can read concealment information only in the outermost narrow area | region R2 of visual field R1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Computer hologram production apparatus, 11 ... Interference fringe recording point memory | storage part, 12 ... Interference fringe recording point setting part, 13 ... Image data memory | storage part, 14 ... Pattern data memory | storage part, 15・ ・ ・ Input unit, 16 ... Image data selection unit, 17 ... Pattern data conversion unit, 18 ... Interference fringe data calculation unit, 19 ... Interference fringe recording device, 50 ... Computer hologram, 60 ... IC card, LS ... light source, O ... three-dimensional object, S ... interference fringe recording surface, RL ... reference light, OL ... object light, E ... observer .

Claims (13)

A computer generated hologram method for creating a computer generated hologram by recording interference fringe data calculated by a computer on a substrate,
An interference fringe recording point writing step for writing an interference fringe recording point indicating a position for recording interference fringe data on the substrate into the interference fringe recording point storage means;
Writing the image data including the shape data and pattern data of the three-dimensional object and the observation angle data in association with each other in the image data storage means;
An input step of inputting pattern data that can be pasted on the image data of the three-dimensional object together with observation angle data;
A conversion step of converting the pattern data of the three-dimensional object corresponding to the observation angle data input in the input step into the pattern data input in the input step;
A calculation step of calculating interference fringe data for each of the interference fringe recording points from the image data of the three-dimensional object obtained by converting the pattern data by the conversion step;
An interference fringe recording step for recording the interference fringe data calculated in the calculation step on the substrate. In the computer generated hologram production method according to claim 1,
The interference fringe recording point writing step includes:
Inputting the shape data and position data of the interference fringe recording surface of the substrate on which the interference fringe data is recorded;
In response to the input of the shape data and the position data of the interference fringe recording surface, a plurality of horizontal slits are set in the vertical direction of the interference fringe recording surface, and a plurality of slits are divided in the horizontal direction by dividing the slit in the horizontal direction. And a step of setting an interference fringe recording point. In the computer generated hologram production method according to claim 1 or 2,
The method for producing a computer generated hologram, wherein the interference fringe recording step records the interference fringe data by changing a light transmittance of a transparent material substrate according to a position. In the computer generated hologram production method according to any one of claims 1 to 3,
In the interference fringe recording step, the interference fringe data is recorded by changing a concavo-convex shape of a substrate surface. A computer generated hologram produced by the computer generated hologram producing method according to any one of claims 1 to 4,
A computer generated hologram characterized in that texture mapping data or bump mapping data is applied only at a specific observation angle so as to have parallax only in the horizontal direction and to change the color and texture of the surface of the three-dimensional object. A computer generated hologram for creating a computer generated hologram by recording interference fringe data calculated by a computer on a substrate,
Interference fringe recording point storage means for storing interference fringe recording points indicating positions for recording interference fringe data on the substrate;
Image data storage means for storing image data including shape data and pattern data of a three-dimensional object and observation angle data in association with each other;
Input means for inputting pattern data that can be pasted on the image data of the three-dimensional object together with observation angle data;
Pattern data conversion means for converting pattern data of a three-dimensional object corresponding to observation angle data input by the input means into pattern data input by the input means;
Interference fringe data calculating means for calculating interference fringe data for each interference fringe recording point from the image data of the three-dimensional object converted from the pattern data;
An apparatus for producing a computer generated hologram, comprising: interference fringe recording means for recording the interference fringe data calculated by the interference fringe data calculating means on the substrate. A computer generated hologram displaying parallax only in the horizontal direction and displaying a three-dimensional object,
The image of the three-dimensional object is applied with texture mapping data or bump mapping data only within a specific observation angle range so that the color and texture of the surface changes according to the observation angle. Computer hologram to do. The computer generated hologram according to claim 7,
A computer generated hologram characterized in that a plurality of texture mapping data or bump mapping data is applied to an image of the three-dimensional object so that the color and texture of the surface changes according to the angle to be observed. The computer generated hologram according to claim 7 or 8,
A computer generated hologram characterized in that images such as characters, symbols, and patterns are represented on a three-dimensional object by texture mapping. The computer generated hologram according to any one of claims 7 to 9,
A computer generated hologram characterized in that an image of a three-dimensional object having a specific color and texture can be observed only in a part of a narrow range within a preset viewing zone. The computer generated hologram according to claim 10,
The computer generated hologram characterized in that the narrow range includes the center of the viewing zone and is a range of 1/5 or less of the entire viewing zone. The computer generated hologram according to claim 10,
The computer generated hologram characterized in that the narrow range includes the outermost side of the viewing zone and is a range of 1/5 or less of the entire viewing zone.   An information printed matter, wherein the computer generated hologram according to any one of claims 7 to 12 is provided in at least a part of a region of a surface of a printed matter base material.

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