JP4977886B2 - Computer-generated hologram reproduction simulation method, computer-generated hologram production method using the reproduction simulation method, and computer-generated hologram produced using the computer-generated hologram production method - Google Patents

Description

  The present invention relates to a computer-generated hologram reproduction simulation method, a computer-generated hologram production method using the reproduction simulation method, and a computer-generated hologram produced using the computer-generated hologram production method.

2. Description of the Related Art Conventionally, there are those in which a hologram is attached to a cash voucher or a credit card or integrally formed to prevent forgery. As this hologram, there are computer-generated holograms that are produced by recording interference fringes on a predetermined recording surface by calculation using a computer (Patent Document 1 and Patent Document 2).
Japanese Patent No. 3708349 Japanese Patent No. 3892619 JP 2002-72837 A JP 2005-215570 A "3D Image Conference '99 -3D Image Conference '99-" Lecture Collection CD-ROM (June 30-July 1, 1999, Kogakuin University Shinjuku Campus), Paper "Image Binary CGH by EB Drawing ( 3)-Improvement of stereoscopic effect by hidden surface removal and shading- "Hologram white light reproduction simulation", Haruyoshi Fujita, Ken Yamaguchi, Hiroshi Yoshikawa, Journal of the Institute of Image Information and Television Engineers, Vol.10, PP.1481-1485 (issued in October 2007)

  However, the conventional computer-generated holograms proposed so far have not been able to confirm the quality of the computer-generated hologram until EB drawing is performed by an electron beam (EB) drawing device.

  The present invention has been made in view of such problems of the prior art, and its purpose is to confirm the quality of a computer-generated hologram before EB drawing, and is necessary for correction related to the quality of the computer-generated hologram. A computer-generated hologram reproduction method for reducing cost and time, a computer-generated hologram production method using the reproduction simulation method, and a computer-generated hologram produced using the computer-generated hologram production method are provided.

  [1] A computer-generated hologram reproduction simulation method according to the present invention solves the above-described problem, and object light and reference light from a virtual object made of a three-dimensional CG (Computer Graphics) model are on a predetermined recording surface. A computer-generated hologram that simulates a reproduced image of a computer-generated hologram produced based on image data showing the intensity distribution obtained by calculating the intensity distribution of the interference wave formed by the computer on the basis of the image data In the reproduction simulation method, a step of dividing the image data calculated by a computer into small regions, a step of generating a set of two-dimensional Fourier transform images obtained by two-dimensional Fourier transforming the image data for each small region, The target pixel and the target pixel for all the pixels of the aggregate of the two-dimensional Fourier transform image A step of performing a smoothing process in which peripheral reference regions are set in order, and a pixel value of each target pixel is averaged based on a pixel value of the peripheral reference region, and the two-dimensional Fourier transform in which the smoothing process is performed Obtaining a simulation image of the computer-generated hologram from a collection of images.

  [2] In the computer-generated hologram manufacturing method of the present invention, a step of creating a three-dimensional CG model and a step of determining parameters for making the created three-dimensional CG model a desired computer-generated hologram computer-generated hologram Calculating the intensity distribution of interference waves formed on the recording surface based on the parameters of the computer-generated hologram determined by the computer-generated hologram, executing the computer-generated hologram reproduction simulation method, and the computer A computer-generated hologram having a step of drawing a computer-generated hologram from image data indicating the intensity distribution of the interference wave after confirming the playback simulation image of the synthesized hologram, and the computer-generated hologram playback simulation method comprises: [1] A reproduction method for simulating computer-generated hologram.

  [3] Furthermore, the computer-generated hologram manufactured according to the present invention uses the computer-generated hologram manufacturing method described in [2].

  According to the present invention, the cost and time required for correction related to the quality of a computer-generated hologram can be reduced by checking the quality of the computer-generated hologram before EB drawing.

  Hereinafter, a computer-generated hologram reproduction simulation method and a computer-generated hologram production method using the reproduction simulation method will be described with reference to the drawings. First, the principle of producing the computer-generated hologram 1 will be described.

  In the present embodiment, as shown in FIG. 1, a method of recording the original image 10 on the recording surface 20 as interference fringes is used. Here, for convenience of explanation, it is assumed that an XYZ three-dimensional coordinate system is defined as shown and the recording surface 20 is placed on the XY plane. When the optical method is used, an object to be recorded is prepared as the original image 10. The object light O emitted from an arbitrary point P on the original image 10 travels toward the entire recording surface 20. On the other hand, the recording surface 20 is irradiated with the reference light R, and interference fringes between the object light O and the reference light R are recorded on the recording surface 20.

To produce a computer-generated hologram at the position of the recording surface 20, the original image 10, the recording surface 20, and the reference light R are defined as data on the computer, and the interference wave intensity at each position on the recording surface 20 is calculated. do it. Specifically, as shown in FIG. 2, the original image 10 is treated as a set of _N point light sources P ₁ , P ₂ , P ₃ ,..., P _i ,. light _{O 1, O 2, O 3} , ..., O i, ..., O N are each calculation point Q (x, y) with progression to the reference light R toward the calculation point Q (x, y) And calculating the amplitude intensity at the position of the calculation point Q (x, y) of the interference wave generated by the interference between the _N object lights O _{1 to} O _N and the reference light R. . The object light and the reference light are usually calculated as monochromatic light. A large number of calculation points corresponding to the required resolution are defined on the recording surface 20, and the calculation of the amplitude intensity is performed for each of these calculation points. A distribution will be obtained.

  A computer-generated hologram in which the original image 10 is recorded as interference fringes can be produced by forming a physical shading pattern or emboss pattern on an actual medium based on such image data showing the intensity distribution. In the form, a simulation is performed before production to confirm the quality of the computer-generated hologram.

  Next, a computer simulation hologram reproduction simulation method will be described. FIG. 3 is a diagram showing a flowchart of the computer-generated hologram reproduction simulation of the first embodiment. The known technique of reproduction simulation is described in detail in Non-Patent Document 2.

  First, in step 1, parameters such as the two-dimensional Fourier transform division size of image data for determining the size of the output simulation image and the parallax information resolution are determined (ST1). Various methods such as discrete Fourier transform (DFT) and fast Fourier transform (FFT) can be applied to the calculation method of the Fourier transform. In the following embodiments, an FFT characterized by high-speed processing is used. Explain how it was. Subsequently, in step 2, image data is read (ST2).

  Next, in step 3, two-dimensional FFT of the image data is performed (ST3). When performing two-dimensional FFT, the image data is divided into small regions as shown in FIG. 4A according to the division size determined in step 1. Two-dimensional FFT is performed for each small area divided into the division sizes shown in FIG. Next, in step 4, a set of two-dimensional FFT images composed of two-dimensional FFT images for each small region as shown in FIG. 5 is output (ST4).

  The two-dimensional FFT image of the small area represents the intensity for each spatial frequency of the grating included in the image data divided into the small areas, and is for each wavelength of light diffracted from all the small areas to the viewpoint of the observer. By obtaining the intensity, a reproduction simulation image can be obtained. This simulation image has more noise and less blur of the reproduction image than the reproduction image of the actual computer-generated hologram. Regarding noise, the difference in pixel value between adjacent pixels in the two-dimensional FFT image of the image data is large. As for the blur of the reconstructed image, when the illumination light has a finite size and distance, the illumination light is incident on the computer-generated hologram from a number of angles so that multiple parallaxes in the left and right directions are reconstructed at the same time. While the reproduced image is blurred as the position moves away from the recording surface, the simulation illumination light is a perfect parallel light or point light source, so even a reproduced image away from the recording surface is a clear simulation This is because an image is obtained.

  Therefore, in order to make the reproduced simulation image closer to the appearance of a real computer-generated hologram, the target pixel and its surrounding reference area are set for all the pixels of the aggregate of the two-dimensional FFT image, and the pixel value of the target pixel is set. It is preferable to add a smoothing process for averaging based on the pixel values of the peripheral reference regions. (For example, in the reference region having the size of 3 pixels vertically and 3 pixels centered on the target pixel as shown in FIG. 6, the pixel value of the target pixel is 0, and the pixel value other than the target pixel is 255 in the reference region. Then, the pixel value of the target pixel becomes 226 by the smoothing process.)

  Therefore, in step 5, it is determined whether smoothing processing is necessary (ST5). If it is determined in step 5 that a smoothing process is necessary, a smoothing process is performed in step 6 (ST6). If it is determined in step 5 that the smoothing process is not necessary, the smoothing process in step 6 is not executed and the process proceeds to step 7.

  Here, the smoothing process will be described. First, a pixel value is set from the intensity distribution of the interference wave on the recording surface. The pixel value is set according to a numerical value of the intensity distribution of the interference wave. Next, a reference area for the target pixel is set. For example, in the present embodiment, as shown in FIG. 7, the target pixel is set to C2, and the reference region is set to 3 × 5 pixels around the target pixel. FIG. 7A shows pixel values before smoothing, and FIG. 7B shows pixel values after smoothing.

In this case, C′2 obtained by smoothing the target pixel C2 = 102 is obtained by the following equation (1).
C'2 = (A1 + A2 + A3 + B1 + B2 + B3 + C1 + C2 + C3 + D1 + D2 + D3 + E1 + E2 + E3) / 15
... (1)

  When formula (1) is calculated, C′2 = 110, which is different from the pixel value of the original target pixel, and is an averaged value based on the pixel value of the reference region. As a result, a two-dimensional FFT image with discrete pixel values of adjacent pixels as shown in FIG. 8A is smoothed as shown in FIG. FIG. 9 is a diagram obtained by smoothing the two-dimensional FFT image of a certain small area shown in FIG.

  Note that when there are no pixels in the reference area, there are a plurality of programming methods, but for example, the reference area may be limited to the existing pixels. In addition, the range of the reference area may be set freely, and in that case, weighting or the like may be set for the pixel values of some areas.

  In step 7, parameters of a computer-generated hologram such as an interference fringe pixel pitch and a reference light angle are input (ST7). Subsequently, in step 8, a viewpoint for observing the computer-generated hologram is set, and the intensity for each wavelength of the diffracted light diffracted in the viewpoint direction from all the divided small regions is calculated (ST8). Next, in step 9, a simulation image is displayed (ST9), and the process ends.

  FIG. 10 is a diagram illustrating a simulation image that is not subjected to the smoothing process and a simulation image that is subjected to the smoothing process. FIG. 10A shows a simulation image without smoothing processing, and FIG. 10B shows a simulation image with smoothing processing.

  In this way, by performing smoothing processing, a plurality of pieces of parallax information are synthesized with a collection of two-dimensional Fourier transform images, and an actual computer-generated hologram illuminated with illumination light having a finite area like a fluorescent lamp A simulation image similar to the appearance of is obtained.

  Moreover, the light source shape can be reflected in the simulation image by setting the reference region of the smoothing process according to the light source shape. For example, a reproduction image of a computer-generated hologram when a light source such as a fluorescent lamp that spreads in the horizontal direction as shown in FIG. 11 is used as illumination light, the blurred image is reproduced as the position of the reproduction image moves away from the hologram surface. However, a blurred simulation image is output by smoothing a collection of two-dimensional FFT images with a reference region extending in the x-axis direction. In the light source arrangement as shown in FIG. 12, when the reproduction wavelength of the computer-generated hologram is 555 nm, the calculation interval of the interference wave in the x-axis direction is 0.5 μm, and the divided small area pixels are 64 × 64 pixels. The size of the reference area may be 21 pixels wide centering on the target pixel as shown in FIG.

  Furthermore, in the reproduction image of the computer-generated hologram when the light source such as a fluorescent lamp having a spread in the depth direction as shown in FIG. 14 is used as the illumination light, the chromatic dispersion in the vertical direction of the computer-generated hologram is averaged, and the saturation An image with reduced saturation is reproduced, but a simulation image with reduced saturation is output by smoothing a collection of two-dimensional FFT images with a reference region extending in the y-axis direction. In the light source arrangement as shown in FIG. 15, when the reproduction wavelength of the computer-generated hologram is 555 nm, the calculation interval of the interference wave in the y-axis direction is 0.2 μm, and the divided small area pixels are 64 × 64 pixels The size of the reference area may be 5 pixels wide centering on the target pixel as shown in FIG.

  Next, a hologram production method using the reproduction simulation method will be described. FIG. 17 is a diagram illustrating a flowchart of a computer-generated hologram manufacturing method using the computer-generated hologram reproduction simulation method of the second embodiment.

  First, in step 11, a three-dimensional CG model as shown in FIG. 18 is created (ST11). Subsequently, in step 12, computer-generated hologram parameters are input (ST12). Here, the computer-generated hologram parameters include an interference fringe calculation interval, a reference light wavelength, an object light divergence angle, an interference fringe pattern period height, an interference fringe pattern repetition period, a computer-generated hologram size, and the like.

  Next, in step 13, object light is calculated (ST13), and in step 14, interference fringes are calculated (ST14). Subsequently, in step 15, it is determined whether simulation is necessary (ST15).

  If it is determined in step 15 that simulation is not necessary, the process proceeds to step 25. If it is determined in step 15 that a simulation is necessary, a computer-generated hologram reproduction simulation is executed. A detailed description of the computer simulation hologram reproduction simulation is omitted with respect to the same parts as in the first embodiment.

  In step 16, parameters such as the two-dimensional FFT division size of the image data for determining the size of the output simulation image and the parallax information resolution are determined (ST 16). Subsequently, in step 17, the image data is read, and the two-dimensional FFT of the image data is performed (ST17). When performing the two-dimensional FFT, as shown in FIG. 4, the image data is divided into the division sizes of the small regions input in step 16, and the two-dimensional FFT is performed for each small region. Next, in step 18, an aggregate of two-dimensional FFT images composed of two-dimensional FFT images for each small region as shown in FIG. 5 is output (ST18).

  Next, in step 19, it is determined whether smoothing processing is necessary (ST19). If it is determined in step 19 that a smoothing process is necessary, a smoothing process is performed in step 20 (ST20). If it is determined in step 19 that the smoothing process is not necessary, the smoothing process in step 20 is not executed and the process proceeds to step 21.

  Since the smoothing process is the same as in the first embodiment, a description thereof will be omitted.

  In step 21, parameters of a computer-generated hologram such as an interference fringe calculation interval and a reference beam angle are input (ST21). Subsequently, in step 22, a viewpoint for observing the computer-generated hologram is set, and the intensity for each wavelength of light diffracted by the viewpoint is calculated (ST22). Next, in step 23, a simulation image is displayed (ST23).

  Subsequently, in step 24, the quality of the computer-generated hologram is confirmed with a simulation image, and it is determined whether or not EB drawing is performed by the electron beam drawing apparatus (ST24). In step 24, the image is confirmed, and when it is determined that EB drawing is not performed with the confirmed image, the process returns to step 1 to correct the parameters of the three-dimensional CG model and the computer-generated hologram as the original image. If the quality of the computer-generated hologram is confirmed in the simulation image in step 24 and it is determined that the EB drawing is performed, the image data indicating the intensity distribution of the interference wave is converted into the EB drawing data in step 25 (ST25). In step 26, EB drawing is performed (ST26), and a computer-generated hologram is produced.

  Here, an example from EB drawing data conversion to computer-generated hologram production will be described.

  If image data showing the intensity distribution is converted into EB drawing data and a physical gray pattern or emboss pattern is formed on an actual medium, a hologram in which the original image 10 is recorded as interference fringes can be produced.

  As a method for forming high-resolution interference fringes on a medium, EB drawing using an electron beam drawing apparatus is suitable. An electron beam drawing apparatus is widely used for drawing a mask pattern of a semiconductor integrated circuit, and has a function of scanning an electron beam with high accuracy. Accordingly, if image data indicating the intensity distribution of the interference wave obtained by calculation is applied to the electron beam drawing apparatus and the electron beam is scanned, an interference fringe pattern corresponding to the intensity distribution can be drawn.

  However, a general electron beam drawing apparatus has only a function of drawing a binary image by controlling drawing / non-drawing. Therefore, the intensity distribution obtained by the calculation may be binarized to create a binary image, and this binary image data may be given to the electron beam drawing apparatus.

  FIG. 19 is a conceptual diagram of a general method for recording an interference fringe pattern using such binarization processing. With the above-described calculation, a predetermined interference wave intensity value, that is, an amplitude intensity value of the interference wave is defined at each calculation point Q (x, y) on the recording surface 20. For example, a predetermined amplitude intensity value is also defined at the calculation point Q (x, y) shown in FIG. Therefore, a predetermined threshold value (for example, an average value of all amplitude intensity values distributed on the recording surface 20) is set for the amplitude intensity value, and an arithmetic point having an intensity value equal to or greater than the threshold value is set. A pixel value “1” is given, and a pixel value “0” is given to a calculation point having an intensity value less than this threshold value. Therefore, a pixel value of “1” or “0” is defined at the calculation point Q (x, y) shown in FIG.

  Therefore, as shown in FIG. 19B, a unit area U (x, y) is defined at the position of the calculation point Q (x, y), and this unit area U (x, y) is set to “1”. If it is handled as a pixel having any pixel value of “0”, a predetermined binary image can be obtained. If the binary image data is supplied to the electron beam drawing apparatus and drawn, interference fringes can be drawn as a physical binary image. Actually, based on the physically drawn interference fringes, for example, an embossed plate is prepared, and embossing using the embossed plate is performed, so that a hologram on which the interference fringes are formed as an uneven structure is formed. Can be mass-produced.

  FIG. 20 shows unit areas U1 to U24 that are two-dimensionally arranged on the recording surface 20. In this example, each unit region is a square having a side of 2 μm, because the calculation points Q1 to Q24 defined on the recording surface 20 are arranged at a pitch of 2 μm vertically and horizontally. . Since the calculation point defined on the recording surface 20 functions as a sample point of the interference wave intensity, the point light source pitch defined on the original image 10, the original image 10 and the recording surface 20, and so on. In consideration of the optical conditions such as the distance, the direction of the reference light R, and the wavelength, they may be arranged at an optimum pitch for recording interference fringes. In the example shown in FIG. 14, the pitch of the calculation points Q is 2 μm in both vertical and horizontal directions, but the vertical and horizontal pitches may be changed (in this case, each unit region is a rectangle). In the example shown in FIG. 20, each unit region is arranged on each calculation point so that the center point of the square unit region overlaps each calculation point. It is not always necessary that the positional relationship is as described above. For example, the upper left corner point of each unit area may be defined as a reference point, and the individual unit areas may be arranged so that the upper left corner reference point overlaps the calculation point.

  As described above, predetermined interference wave intensity values are calculated at the calculation points Q1 to Q24 shown in FIG. In the conventional general method, each intensity value is binarized based on a predetermined threshold value and converted into a pixel value of “1” or “0”. Therefore, for example, if the unit area U including the calculation point Q in which the pixel value “1” is defined is treated as a white pixel and the unit area U including the calculation point Q in which the pixel value “0” is defined as a black pixel, Thus, a binary image is obtained. If a physical concavo-convex structure is formed on the basis of the binary image, the white pixel portion is a concave portion and the black pixel portion is a convex portion (or vice versa), a hologram medium can be obtained.

  However, in such a general method for producing a computer-generated hologram, since it is limited to either a white pixel or a black pixel that can be assigned to each unit area, the interference wave obtained by the calculation is used. The intensity gradation value is lost.

  Therefore, in the present embodiment, a binary pattern defined by dividing a unit area into a first area having a first pixel value and a second area having a second pixel value is expressed as “ A plurality of types are prepared by changing the occupancy ratio of the first area with respect to the unit area, and the occupancy ratios corresponding to the interference wave intensities at the respective calculation points (the “first area with respect to the unit area”) are prepared. The binary pattern having the area occupancy ratio “)” is assigned.

  First, as shown in FIG. 21, a specific gradation value is assigned to a pixel according to the value of the interference wave intensity. In the present embodiment, as shown in FIG. 22, five types of binary patterns D0 to D4 are prepared in advance. Each of the binary patterns is a pattern in a unit region made up of a square having a side of 2 μm, and includes a first region having a first pixel value “1” (a white portion in the figure) and a second pixel value. And a second region having “0” (the hatched portion in the figure). Of course, the binary pattern D0 includes only the second region, and the binary pattern D4 includes only the first region. For convenience, the area of the other region is 0. Consider a special case. Here, paying attention to “occupancy ratio of the first area (white portion) with respect to the unit area (entire square)”, the occupancy ratios of the binary patterns D0, D1, D2, D3, D4 are 0%, 25%, 50%, 75%, and 100%.

  In any binary pattern, as shown in the figure, the first area (white portion) has a vertical width equal to the vertical width of the unit area (whole square) and has a horizontal width corresponding to a predetermined occupation ratio. In addition, the rectangle constituting the first area is arranged at the center position with respect to the lateral width of the unit area. And the remaining part in which the 1st field in a unit field is arranged serves as the 2nd field (part given hatching). The binary pattern is not limited to that shown in FIG. 22, but may be various patterns as shown in FIG. 23 or other patterns. Further, gradation may be expressed by making each refractive pattern correspond to a different refractive index.

  Now, by selectively assigning the five types of binary patterns D0 to D4 thus prepared to the respective calculation point positions on the recording surface, the interference wave intensity at each calculation point is expressed by five levels of gradation. Is possible. In the example shown in FIG. 21, the interference wave intensity at each calculation point is given as five levels of intensity values from 0 to 4. In order to assign five types of binary patterns D0 to D4 to the five levels of intensity values, for example, a binary pattern D0 for intensity value 0, a binary pattern D1 for intensity value 1, and an intensity value 2 Corresponding relationships such as the binary pattern D2 and the intensity value 3 for the binary pattern D3 and the intensity value 4 for the binary pattern D4 may be defined in advance. FIG. 23 is a diagram illustrating an example of a binary image obtained by assigning a binary pattern corresponding to each intensity value illustrated in FIG. 21 based on the above-described correspondence relationship. Compared to a binary image obtained by a general method, all of them are binary images, but the interference wave intensity value at each calculation point is expressed with gradation information.

  When a binary image as shown in FIG. 24 is obtained, a computer capable of reproducing a high-quality gradation image by forming physical interference fringes on the medium based on the binary image. A synthetic hologram medium is obtained. Specifically, an embossed structure having a black portion in FIG. 24 as a convex portion and a white portion as a concave portion (or vice versa) may be formed on the medium. In practice, it is preferable to form such a binary image by electron beam scanning using an electron beam drawing apparatus. At present, a spot pattern of an electron beam in a generally used electron beam lithography apparatus is about 0.05 μm, the scanning accuracy is about 0.01 μm, and a binary pattern having a dimensional configuration as shown in FIG. If so, it can be drawn sufficiently. Of course, the process up to obtaining the binary image as shown in FIG. 24 is performed by a computer in which a predetermined program is incorporated, and the binary image data produced by this computer is provided to the electron beam drawing apparatus. The physical drawing process is performed.

  FIG. 25 is a reproduced image of the produced computer-generated hologram. Thus, it can be seen that the simulation image subjected to the smoothing process shown in FIG. 10B is an image close to the reproduced image of the produced computer-generated hologram.

  Therefore, by performing the smoothing process, a plurality of pieces of parallax information are combined with a collection of two-dimensional FFT images, and the appearance of an actual computer-generated hologram illuminated with illumination light having a finite area, such as under a fluorescent lamp, A similar simulation image is obtained. In addition, since a computer-generated hologram is produced by EB drawing after performing a simulation in advance and confirming the simulation result before performing EB drawing, the cost and time required for correcting the computer-generated hologram can be reduced.

  In the present embodiment, the intensity distribution of the interference wave is used to produce the computer-generated hologram 1. However, a complex amplitude distribution may be applied without causing interference with the reference light.

  For example, as described in Patent Documents 3 and 4, the phase may be recorded by the depth of the groove of a three-dimensional cell having a groove on one side, and the amplitude may be recorded by the width of the groove.

  Alternatively, as described in A.N. W. You may make it record an amplitude and a phase by the method of Lohmann etc., the method of Lee, etc.

In the present embodiment, the EB drawing apparatus is used for producing the computer-generated hologram. However, a laser drawing apparatus or a cutting process may be used.

  In this embodiment, the original image 10 is handled as a set of point light sources, but a method of handling the original image described in Patent Document 2 as a set of line light sources may be used.

  In this way, the computer-generated hologram production method using the reproduction simulation method confirms the quality of the computer-generated hologram before EB drawing, thereby reducing the cost and time loss required for corrections related to the quality of the computer-generated hologram. Therefore, the produced computer-generated hologram is a high-quality computer-generated hologram at low cost.

  The computer-generated hologram reproduction simulation method of the present invention, the computer-generated hologram production method using the reproduction simulation method, and the computer-generated hologram produced using the computer-generated hologram production method have been described above based on the embodiments. However, the present invention is not limited to these embodiments, and various modifications are possible.

It is a perspective view which shows the concept of the recording method of a computer composition hologram. It is a figure which shows the specific example based on the concept of the arithmetic processing of FIG. It is a figure which shows the flowchart of the reproduction simulation of the computer composition hologram of 1st Embodiment. It is a figure which shows the image data which shows intensity distribution of the interference wave divided | segmented into the small area | region. It is a figure which shows the two-dimensional FFT image of a small area | region. It is a figure which shows the concept of the smoothing process. It is a figure which shows the partial pixel value of the two-dimensional FFT image before and behind performing the smoothing process of this embodiment. It is a figure which shows the one part enlarged view of the two-dimensional FFT image before and behind performing the smoothing process of this embodiment. It is the figure which smoothed the two-dimensional FFT image of the small area | region shown in FIG. It is a figure which shows the simulation image which performed the smoothing process, and the simulation image which does not perform a smoothing process. It is a perspective view which shows the concept of the illumination by the light source which spreads in a horizontal direction. It is a figure which shows the specific example based on the concept of FIG. It is a figure which shows the reference area | region of the smoothing process of this embodiment in FIG. It is a perspective view which shows the concept of the illumination by the light source which spreads in the depth direction. It is a figure which shows the specific example based on the concept of FIG. It is a figure which shows the reference area | region of the smoothing process of this embodiment in FIG. It is a figure which shows the flowchart of the hologram production method using the reproduction | regeneration simulation method of the computer-generated hologram of 2nd Embodiment. It is a figure which shows the produced three-dimensional CG model. It is a figure which shows the concept which acquires a binary image from interference wave intensity distribution. It is a figure which shows the area | region arranged in the grid | lattice form on the recording surface form. It is a figure which shows the quinary interference fringe intensity | strength of each area | region. It is a figure which shows the structure of a binary pattern. It is a figure which shows the structure of another binary pattern. It is a figure which shows the binary image obtained by this embodiment. It is the reproduction image of the produced computer-generated hologram.

Explanation of symbols

10 ... Original image 20 ... Recording surface

Claims (3)

It is created based on image data indicating the intensity distribution obtained by computing the intensity distribution of the interference wave formed on the predetermined recording surface by the object light and the reference light from the virtual object made of a three-dimensional CG model. In a computer-generated hologram reproduction simulation method for simulating a reproduced image of a computer-generated hologram by a computer based on the image data,
Dividing the image data calculated by a computer into small regions;
Generating a set of two-dimensional Fourier transform images obtained by two-dimensional Fourier transforming the image data for each small area;
The target pixel and the reference region around the target pixel are sequentially set for all the pixels of the aggregate of the two-dimensional Fourier transform image, and the pixel value of each target pixel is based on the pixel value of the peripheral reference region. Performing a smoothing process to average;
Obtaining a simulation image of the computer-generated hologram from an aggregate of the two-dimensional Fourier transform images subjected to the smoothing process;
A computer-generated hologram reproduction simulation method characterized by comprising: Creating a three-dimensional CG model;
Determining parameters for making the created three-dimensional CG model a desired computer-generated hologram;
Calculating the intensity distribution of the interference wave formed on the recording surface based on the parameters of the computer-generated hologram by a computer;
Executing a computer-generated hologram reproduction simulation method;
Drawing a hologram from image data indicating an intensity distribution of interference waves after confirming a reproduction simulation image of the computer-generated hologram;
Is a method for producing a computer-generated hologram having
The computer-generated hologram reproduction simulation method is the computer-generated hologram reproduction simulation method according to claim 1. The computer-generated hologram production method using the computer-generated hologram reproduction simulation method.   A computer-generated hologram produced by a computer-generated hologram manufacturing method using the computer-generated hologram reproduction simulation method according to claim 2.