Hologram data generation device and program

Abstract

To provide a hologram data generator which can generate hologram data with reduced information amount.SOLUTION: A hologram data generator 1 includes: phase addition means 10 for adding a phase to object target data and generating a complex amplitude distribution; propagation calculation means 11 for calculating the complex amplitude distribution of a hologram surface by a propagation calculation; hologram data calculation means 12 for calculating hologram data from the complex amplitude distribution of the hologram surface and the complex amplitude distribution of reference light; and hologram data thinning means 13 for thinning data in a preset missing pixel position from the hologram data calculated by the hologram data calculation means 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention is a hologram data generation device. and Regarding the program. [Background technology]

[0002] Holography is a technique that utilizes the interference and diffraction of light to faithfully reproduce the wavefront of light emitted from an object. This holography is known as an ideal three-dimensional imaging technique free from convergence and accommodation contradictions. Furthermore, a medium on which three-dimensional information of an object is recorded using holographic technology is called a hologram. Electronic holography is a technique that treats this hologram as digital data and displays the hologram data on an electronic device called a spatial light modulator (SLM) to display a three-dimensional image as a moving image.

[0003] The viewing angle (2θ) at which a 3D image reproduced by electronic holography can be correctly observed depends on the pixel pitch p of the SLM and the wavelength λ of the incident light, where 2θ = 2sin -1 This is expressed as [λ / (2p)]. Therefore, in order to expand the viewing angle, it is necessary to narrow the pixel pitch of the SLM. On the other hand, if the number of pixels in the width direction of the SLM is Nx, the number of pixels in the height direction of the SLM is Ny, and the pixel pitch of the SLM is p, then the area S of the SLM is S = p 2 Since it is NxNy, increasing the pixel count of the SLM is necessary to enlarge the screen size of 3D images. Conventionally, there are technologies for enlarging such 3D images to a large screen by arranging multiple SLMs horizontally and vertically to increase the number of pixels across the entire SLM (see Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-215332 [Overview of the project] [Problems that the invention aims to solve]

[0005] In hologram reproduction, for example, to obtain a viewing angle of 30° at a wavelength of 532nm, an SLM with a pixel pitch of 1μm is required. And, for example, 10cm 2 Using an SLM of that size would require handling a massive amount of hologram data, specifically 100k x 100k pixels. Thus, with conventional methods, when scaling up 3D images to a large screen, the amount of information in the hologram data becomes enormous, leading to problems such as increased time required to record the hologram data onto the recording medium, transmit the hologram data to the display device, and write the hologram data to the display device.

[0006] This invention has been made in view of the above-mentioned conventional problems, and is a hologram data generation device capable of generating hologram data with reduced information content. and The objective is to provide a program. [Means for solving the problem]

[0007] To solve the aforementioned problems, the hologram data generation apparatus according to the present invention is a hologram data generation apparatus that generates hologram data in which a part of the pixels is missing from subject data which is three-dimensional data, and comprises a phase addition means, a propagation calculation means, a hologram data calculation means, and a hologram data decimation means.

[0008] In this configuration, the hologram data generation device generates a complex amplitude distribution by adding phase to the subject data using a phase-adding means. The hologram data generation device then uses propagation calculation means to calculate the complex amplitude distribution of the hologram surface from the complex amplitude distribution of the subject data through propagation calculation. The hologram data generation device then calculates the hologram data from the complex amplitude distribution of the hologram surface and the complex amplitude distribution of the reference light using a hologram data calculation means. This generates the hologram data.

[0009] Furthermore, the hologram data generation device uses a hologram data decimation means to decimate data at preset missing pixel locations from the hologram data calculated by the hologram data calculation means. This reduces the amount of information in the hologram data. In this way, the hologram data with downsampled pixels is displayed as a reconstructed image of the subject by an electronic holography display device, which interpolates the missing pixels with arbitrary pixel values. In this case, the user does not perceive the location of the missing pixels in the reconstructed image of the subject through the hologram reconstruction. Furthermore, the hologram data generation device can be operated using a hologram data generation program that enables the computer to function as each of the aforementioned means. [Effects of the Invention]

[0012] The present invention provides the following excellent effects. According to the present invention, it is possible to generate hologram data with reduced information content. 。 As a result, the present invention can shorten the time required to record hologram data, transmit it, and write it to a display device compared to conventional methods. [Brief explanation of the drawing]

[0013] [Figure 1] This is a block diagram showing the configuration of a hologram data generation device according to an embodiment of the present invention. [Figure 2] This is an explanatory diagram illustrating the process by which the propagation calculation means in Figure 1 calculates the complex amplitude distribution of the hologram plane from the complex amplitude distribution of the tomographic image. [Figure 3A]It is an explanatory diagram for explaining an example of thinning out hologram data for each row in the hologram data thinning means of FIG. 1. [Figure 3B] It is an explanatory diagram for explaining an example of thinning out hologram data for each column in the hologram data thinning means of FIG. 1. [Figure 3C] It is an explanatory diagram for explaining an example of thinning out hologram data for each block in the hologram data thinning means of FIG. 1. [Figure 3D] It is an explanatory diagram for explaining an example of randomly thinning out hologram data in the hologram data thinning means of FIG. 1. [Figure 4] It is a flowchart showing the operation of a hologram data generation device according to an embodiment of the present invention. [Figure 5] It is a block configuration diagram showing the configuration of an electronic holography display device according to an embodiment of the present invention. [Figure 6] It is a flowchart showing the operation of an electronic holography display device according to an embodiment of the present invention. [Figure 7] It is a graph showing the image quality evaluation between the image obtained by simulating and reproducing hologram data in which pixels missing due to thinning are interpolated and the original image. The horizontal axis represents the ratio of missing pixels to all pixels (missing data amount [%]), and the vertical axis represents PSNR (maximum signal-to-noise ratio [dB]). [Figure 8] It is a block configuration diagram showing a modified example of a hologram data generation device using the GS algorithm for propagation calculation. [Figure 9] It is a graph showing the image quality evaluation between the image obtained by simulating and reproducing hologram data in which pixels missing due to thinning are interpolated using the GS algorithm for propagation calculation and the original image. The horizontal axis represents the ratio of missing pixels to all pixels (missing data amount [%]), and the vertical axis represents PSNR (maximum signal-to-noise ratio [dB]).

Mode for Carrying Out the Invention

[0014] [Configuration of Hologram Data Generation Device] First, with reference to Figure 1, the configuration of the hologram data generation device 1 according to an embodiment of the present invention will be described. The hologram data generation device 1 generates hologram data from three-dimensional subject data by removing some of the pixels. The subject data can be any type of 3D data. Here, we will explain using an example of a tomographic image composed of 3D data organized by distance. As shown in Figure 1, the hologram data generation device 1 comprises a phase addition means 10, a propagation calculation means 11, a hologram data calculation means 12, a hologram data decimation means 13, and a condition data storage means 14.

[0015] The phase addition means 10 adds phase to the subject data to generate a complex amplitude distribution. The phase addition means 10 receives subject data via an input means (not shown in the illustration). The phase addition means 10 then takes the value of each pixel in the subject data as the amplitude and adds an initial phase (for example, random phase, equiphase, linear phase, etc.) to each pixel. As a result, the subject data becomes a complex amplitude distribution. The phase addition means 10 outputs the complex amplitude distribution generated by adding the initial phase to the propagation calculation means 11.

[0016] The propagation calculation means 11 calculates the complex amplitude distribution of a predetermined hologram surface from the complex amplitude distribution of the subject data generated by the phase addition means 10 through propagation calculation. The propagation calculation in the propagation calculation means 11 is not particularly limited and can be the angular spectral method, Fresnel propagation method, etc.

[0017] Here, with reference to Figure 2, an example of using the angular spectral method for propagation calculation in the propagation calculation means 11 will be explained. The propagation calculation means 11 considers the display surface of the spatial light modulator (SLM100) as the hologram surface H, and the distance from the hologram surface H (z i Multiple complex amplitude distributions U for each of the ) i (x,y,z iFrom this, the complex amplitude distribution U(x, y, 0) on the hologram plane H is calculated. Specifically, when the propagation calculation means 11 sets the number of samplings in the depth direction of the tomographic image to N z and z i is the propagation distance to the hologram plane H of the i-th tomographic image, the complex amplitude distribution U(x, y, 0) on the hologram plane H (z = 0) is calculated by the following formula (1).

[0018] [Number]

[0019] Here, FT is the fast Fourier transform (FFT), and FT -1 is the inverse fast Fourier transform (IFFT), x and y are spatial coordinates, and u and v represent the spatial frequencies in the x-direction and y-direction, respectively. At this time, for the pixels at the positions that are the targets of the missing hologram data stored in the condition data storage means 14, the propagation calculation means 11 may have indefinite values or may set specific values (for example, "0"). Returning to FIG. 1, the description of the configuration of the hologram data generation device 1 will be continued.

[0020] The propagation calculation means 11 outputs the complex amplitude distribution on the hologram plane calculated by the propagation calculation to the hologram data calculation means 12.

[0021] The hologram data calculation means 12 calculates hologram data from the complex amplitude distribution of the hologram plane calculated by the propagation calculation means 11 and the complex amplitude distribution of the reference light. The hologram data calculation means 12 calculates hologram data by using the complex amplitude distribution U(x, y, 0) of the hologram plane as the complex amplitude distribution of the object light and the complex amplitude distribution of the reference light prepared in advance.

[0022] The complex amplitude distribution of the reference light is stored in the condition data storage means 14 in advance. The wavefront of the reference light may be an arbitrary wavefront such as a plane wave or a spherical wave. Furthermore, the hologram data generated by the hologram data calculation means 12 may be of amplitude type, phase type, or complex amplitude type. Since the method for generating hologram data from the complex amplitude distribution of object light and the complex amplitude distribution of reference light can be done using general methods, a detailed explanation will be omitted here. The hologram data calculation means 12 outputs the hologram data obtained by the calculation to the hologram data decimation means 13.

[0023] The hologram data decimation means 13 decimates the data at pre-set missing pixel locations from the hologram data calculated by the hologram data calculation means 12. In other words, the hologram data decimation means 13 generates missing hologram data by decimating the data at the predetermined missing pixel positions. Here, the locations of the missing pixels are pre-stored in the condition data storage means 14, and the hologram data decimation means 13 generates missing hologram data by decimating the pixels at the locations of the missing pixels set in the condition data storage means 14.

[0024] The hologram data thinning means 13 transmits the missing hologram data to an electronic holography display device (see Figure 4) via a transmission means (not shown). Alternatively, the hologram data thinning means 13 records the missing hologram data on a recording medium (not shown) and has the electronic holography display device (see Figure 4) read it.

[0025] Here, we will explain examples of missing pixel locations with reference to Figures 3A to 3D. In this example, the hologram data HD consists of 16 pixels in the horizontal (x) direction and 16 pixels in the vertical (y) direction, with normal pixels (pixels that are not missing) NP represented in white and missing pixels TP represented in black.

[0026] Figure 3A shows an example of deleting (downsampling) pixels row by row from hologram data HD. Here, every four rows are designated as rows with missing pixels. Note that there does not need to be only one row of missing pixels; there can be multiple rows. Also, the spacing between rows of missing pixels does not need to be equal.

[0027] Figure 3B shows an example of deleting (downsampling) pixels from hologram data HD column by column. Here, every four columns are used as a column of missing pixels. Note that the column of missing pixels does not have to be a single column; it can be multiple columns. Also, the spacing between the columns of missing pixels does not have to be equal.

[0028] Figure 3C shows an example of deleting (downsampling) pixels block by block from hologram data HD. Here, each 2x2 pixel block is treated as a deleting pixel block. Note that the number of horizontal and vertical pixels in a deleting pixel block is not limited to 2x2. Also, the spacing between deleting pixel blocks does not have to be equal.

[0029] Figure 3D shows an example of randomly deleting (downsampling) pixels from hologram data HD. Here, randomly deleting pixels are set across the entire hologram data HD. However, randomly deleting pixels may also be set within a block of a predetermined size (for example, an 8x8 pixel block), and these blocks may be repeated horizontally and vertically. Returning to Figure 1, we will continue our explanation of the configuration of the hologram data generation device 1.

[0030] The condition data storage means 14 stores various condition data for generating hologram data. The condition data storage means 14 can be made of a general storage medium such as a semiconductor memory. The condition data storage means 14 pre-stores, as condition data, the location of missing pixels used by the propagation calculation means 11 and the hologram data decimation means 13, the number of grayscale levels, and so on. The condition data storage means 14 also pre-stores, as condition data, the complex amplitude distribution of the reference light used by the hologram data calculation means 12. Furthermore, the condition data storage means 14 stores various conditions for generating hologram data, such as the modulation method (phase modulation type, amplitude modulation type, complex amplitude modulation type), the number of gradations, and the size of the hologram.

[0031] As explained above, the hologram data generation device 1 generates hologram data by thinning out predetermined missing pixels using the hologram data thinning means 13. Therefore, when displaying a large-screen 3D image, the amount of information in the hologram data can be reduced. Furthermore, the hologram data generation device 1 can be operated using a hologram data generation program that enables a computer (not shown in the figure) to function as each of the aforementioned means.

[0032] [Operation of the hologram data generation device] Next, with reference to Figure 4 (and Figure 1 as appropriate for the configuration), the operation of the hologram data generation device 1 according to an embodiment of the present invention will be described. It should be assumed that the condition data storage means 14 has various condition data for generating missing hologram data stored in advance.

[0033] In step S1, the phase addition means 10 receives subject data, which is 3D data, via an input means (not shown). In step S2, the phase-adding means 10 takes the value of each pixel of the subject data input in step S1 as the amplitude and adds an initial phase (for example, a random phase) to each pixel. As a result, the subject data becomes a complex amplitude distribution. In step S3, the propagation calculation means 11 generates a predetermined complex amplitude distribution of the hologram surface from the complex amplitude distribution of the subject data generated in step S2 by propagation calculation such as the angular spectral method.

[0034] In step S4, the hologram data calculation means 12 uses the complex amplitude distribution on the hologram surface generated in step S3 as the complex amplitude distribution of object light, and generates hologram data using the complex amplitude distribution of a pre-prepared reference light. In step S5, the hologram data decimation means 13 decimates the pixels at the locations of missing pixels from the hologram data generated in step S4. As a result, the hologram data generation device 1 can generate hologram data with reduced data volume (missing hologram data).

[0035] [Configuration of an electronic holography display device] Next, with reference to Figure 5, the configuration of the electronic holography display device 2 according to an embodiment of the present invention will be described. The electronic holography display device 2 displays a reconstructed image of the subject from the missing hologram data generated by the hologram data generation device 1 (see Figure 1). As shown in Figure 5, the electronic holography display device 2 comprises a missing data storage means 20, a missing pixel interpolation means 21, a display means 22, and a light-emitting means 23.

[0036] The missing data storage means 20 stores missing data information in advance for interpolating missing pixels in the missing hologram data. The missing data storage means 20 can be made of a general storage medium such as a semiconductor memory. The missing data storage means 20 stores missing data information in advance, such as the position of the missing pixel and the number of grayscale levels. The missing data information may also include a fixed pixel value to be assigned to all missing pixels.

[0037] The missing pixel interpolation means 21 interpolates pixels into the missing pixels of the missing hologram data. The missing pixel interpolation means 21 receives the missing hologram data generated by the hologram data generation device 1 (see Figure 1) via an input means (not shown). The missing pixel interpolation means 21 then interpolates the missing pixels in the missing hologram data by inserting pixels at the positions of the missing pixels stored in the missing data storage means 20. At this time, the values ​​of the pixels to be interpolated may be any values, or the pixel values ​​stored in the missing data storage means 20 may be used. Furthermore, the location of the missing pixels does not need to be stored in the missing data storage means 20 in advance; it may be input externally as data associated with the missing hologram data.

[0038] This allows the missing pixel interpolation means 21 to interpolate the missing pixels TP shown in Figures 3A to 3D, for example, to generate hologram data HD. The missing pixel interpolation means 21 outputs the hologram data with the missing pixels interpolated to the display means 22.

[0039] The display means 22 displays hologram data in which missing pixels have been interpolated by the missing pixel interpolation means 21. Note that the data for missing pixels does not depend on the input hologram data. Therefore, the missing pixel interpolation means 21 does not need to write the data for missing pixels to the display means 22 every frame. The display means 22 can be composed of a spatial light modulator (SLM). If the spatial light modulator is a reflective liquid crystal, the display means 22 reproduces the reproduced image by being illuminated from the front by light emitted from the light-emitting means 23 as illumination light. If the spatial light modulator is a transmissive liquid crystal, the display means 22 reproduces the reproduced image by being illuminated from the back by light emitted from the light-emitting means 23 as illumination light.

[0040] The light-emitting means 23 illuminates the display means 22 with illumination light. The light-emitting means 23 includes, for example, a laser light-emitting device and two convex lenses as a light source. The first convex lens expands the diameter of the laser light emitted by the laser light-emitting device, and the second convex lens converts it into parallel light, which is then irradiated onto the display means 22.

[0041] As explained above, the electronic holography display device 2 can interpolate missing pixels in the missing hologram data and display a reconstructed image. Furthermore, the electronic holography display device 2 can be operated using an electronic holography display program that enables a computer (not shown in the figure) to function as each of the aforementioned means.

[0042] [Operation of Electronic Holographic Display Devices] Next, with reference to Figure 6 (and Figure 5 as appropriate for the configuration), the operation of the electronic holography display device 2 according to an embodiment of the present invention will be described. It should be assumed that the missing data storage means 20 has missing data information for interpolating missing pixels in the missing hologram data stored in advance.

[0043] In step S10, the missing pixel interpolation means 21 receives the missing hologram data generated by the hologram data generation device 1 (see Figure 1) via an input means (not shown). In step S11, the missing pixel interpolation means 21 generates hologram data with the missing pixels interpolated by inserting pixels into the missing hologram data at the positions of the missing pixels stored in the missing data storage means 20. In step S12, the display means 22 displays the hologram data generated in step S11. At this time, the display means 22 displays the reconstructed image by being illuminated with illumination light from the light-emitting means 23. This allows the electronic holography display device 2 to display a reconstructed image of a three-dimensional subject from the missing hologram data.

[0044] (Regarding image quality due to missing pixels) Here, we will explain the results of a simulation that shows the quality of the reconstructed image when missing pixels are introduced into the hologram data. Here, as subject data, we used a mandrill image publicly available in a standard image database for simplicity. The display means 22 (SLM) to be displayed has 1024 × 1024 pixels. Since the subject data image is 512 × 512 pixels, we filled the surrounding area with zeros to make it 1024 × 1024 pixels. The display device 22 is a phase-modulated SLM. The number of gradations is 8 bits, and the pixel pitch is 1 μm both horizontally and vertically. In addition, a random phase was added as the initial phase. The initial phase was optimized by performing 50 iterative calculations using the GS algorithm described later. The reference light was a plane wave incident perpendicularly to the display device 22.

[0045] The distance z between the subject plane and the hologram plane (SLM) was set to z = Np / 2tanθ, which eliminates errors in propagation calculations and maximizes the in-plane resolution of the reconstructed image. Here, N is the number of pixels in one direction of the SLM (here, "1024"), p is the pixel pitch (here, "1"), and θ is half of the viewing angle (θ = sin). -1 [λ / (2p)], where λ is the wavelength of light.

[0046] Under these conditions, hologram data was generated from subject data, and after randomly deleting some of the data (pixel value "0"), the subject data was regenerated by performing backpropagation calculations. The original subject data (original image) and the regenerated subject data (reconstructed image) were then compared and evaluated. Here, the PSNR (Maximum Signal-to-Noise Ratio), an objective image quality evaluation index, was used to evaluate the image quality of the reproduced images. Note that other objective image quality evaluation indices, such as SSIM (Structural Similarity Index), or subjective evaluation experiments may also be used for image quality evaluation.

[0047] Figure 7 shows the simulation results. In the graph in Figure 7, the horizontal axis represents the percentage of missing pixels relative to the total number of pixels (missing data amount [%]), and the vertical axis represents the PSNR (maximum signal-to-noise ratio [dB]). Here, the amount of data loss was set from 0.5% to 50%. As shown in Figure 7, image quality (PSNR) deteriorates as the amount of missing data increases. This result is the same if the ratio of the number of pixels in the SLM to the original image is equal. Even if hologram data is corrupted by the hologram data generation device 1, the reconstructed image will not appear to have missing pixels, but rather the overall image quality will be affected. Therefore, the hologram data generation device 1 can determine the amount of missing data within a range of image quality acceptable to the user. This makes it possible to reduce the amount of hologram data.

[0048] [Modified version of a hologram data generation device] Next, referring to Figure 8, we will describe Hologram Data Generation Device 1B, which is a modified version of the Hologram Data Generation Device.

[0049] Hologram data generation device 1B generates hologram data by deleting some pixels from three-dimensional subject data, and is the same as hologram data generation device 1 (see Figure 1). As shown in Figure 8, the hologram data generation device 1B comprises a phase addition means 10, a propagation calculation means 11B, a hologram data calculation means 12, a hologram data decimation means 13, and a condition data storage means 14. The configuration other than the propagation calculation means 11B is the same as that of the hologram data generation device 1 (see Figure 1), so its explanation is omitted.

[0050] The propagation calculation means 11B calculates the complex amplitude distribution of a predetermined hologram surface from the complex amplitude distribution of the subject data generated by the phase addition means 10 through propagation calculation. Note that the propagation calculation means 11 shown in Figure 1 only performs the propagation calculation from the subject plane to the hologram plane once. In contrast, the propagation calculation means 11B uses the GS (Gerchberg-Saxton) algorithm to repeatedly perform the "propagation calculation" from the subject plane to the hologram plane and the "backpropagation calculation" from the hologram plane to the subject plane, while applying "constraint conditions" (subject plane constraint conditions, hologram plane constraint conditions) to both planes.

[0051] The propagation calculation means 11B calculates the complex amplitude distribution on the hologram surface by performing a propagation calculation on the complex amplitude distribution generated by the phase addition means 10, for example, using equation (1). For example, when creating phase-modulated hologram data, the propagation calculation means 11B extracts only the phase of the complex amplitude distribution on the hologram surface as a hologram surface constraint condition. In this case, the propagation calculation means 11B assigns a specific value (e.g., "0") to the pixels corresponding to missing pixels. Then, the propagation calculation means 11B performs a backpropagation calculation corresponding to equation (1) on the phase distribution and calculates the complex amplitude distribution on the subject surface. Then, the propagation calculation means 11B replaces the amplitude of the complex amplitude distribution on the subject surface with the pixel value (amplitude) of the original subject surface as a subject surface constraint condition.

[0052] The propagation calculation means 11B can optimize the phase distribution by repeatedly performing propagation and backpropagation calculations with constraints applied using the GS algorithm. The propagation calculation means 11B terminates the iterative calculation using the GS algorithm after a predetermined number of iterations (for example, 50 times), or when the amount of variation in the complex amplitude distribution on the hologram surface falls below a threshold. The propagation calculation means 11B outputs the complex amplitude distribution on the hologram surface obtained by the GS algorithm to the hologram data calculation means 12.

[0053] As a result, the hologram data generation device 1B can generate hologram data with better image quality than the hologram data generation device 1. The missing hologram data generated by this hologram data generation device 1B can be reproduced as a three-dimensional image of the subject by the electronic holography display device 2 (see Figure 5). Furthermore, the hologram data generation device 1B can be operated using a hologram data generation program that enables a computer (not shown in the figure) to function as each of the aforementioned means.

[0054] The operation of this hologram data generation device 1B differs only from the operation of step S3 of the hologram data generation device 1 described in Figure 4, in that it uses the GS algorithm; therefore, a detailed explanation is omitted.

[0055] (Regarding image quality using the GS algorithm) Here, we will explain the results of a simulation of the quality of the reconstructed image by generating hologram data using the GS algorithm and introducing missing pixels into the hologram data.

[0056] Figure 9 shows the simulation results. In the graph in Figure 9, the horizontal axis represents the percentage of missing pixels relative to the total number of pixels (missing data amount [%]), and the vertical axis represents the PSNR (maximum signal-to-noise ratio [dB]). The subject data and other conditions used are the same as those described in the simulation in Figure 7. Comparing the results in Figure 7 and Figure 9, the results in Figure 9, i.e., using the GS algorithm, show that image quality degradation can be minimized. For example, if the amount of missing data is 25%, using the GS algorithm can improve image quality by approximately 4 dB.

[0057] The configuration and operation of the hologram data generation apparatus 1, 1B and the electronic holography display device 2 according to embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. For example, while tomographic images were used as subject data here, point cloud data, polygon data, depth images, multi-view image sets, etc., may also be used. Furthermore, in the examples shown in Figures 3A to 3D, the ratio of missing pixels (amount of missing data) to the total pixels of the hologram data HD is shown as 25%. However, this ratio can be any ratio as long as the image quality degradation when hologram playback is within an acceptable range for the user. [Explanation of Symbols]

[0058] 1.1B Hologram Data Generation Device 10. Phase Addition Means 11,11B Propagation calculation means 12 Hologram data calculation means 13 Hologram data thinning method 14. Condition data storage means 2. Electronic Holographic Display Device 20. Means for storing missing data 21 Missing Pixel Interpolation Means 22 Display means (spatial light modulator) 23 Light-emitting means

Claims

1. A hologram data generation device that generates hologram data by deleting some pixels from three-dimensional subject data, A phase-adding means for generating a complex amplitude distribution by adding phase to the subject data, A propagation calculation means that calculates the complex amplitude distribution of the hologram surface from the complex amplitude distribution of the subject data by propagation calculation, A hologram data calculation means that calculates hologram data from the complex amplitude distribution of the hologram surface and the complex amplitude distribution of the reference light, A hologram data decimation means that decimates data at pre-set missing pixel positions from the hologram data calculated by the hologram data calculation means, A hologram data generation device characterized by comprising the following features.

2. The hologram data generation apparatus according to claim 1, characterized in that the hologram data thinning means thins out data from the hologram data row by row, column by column, block by block, or randomly, as the missing pixel positions.

3. The hologram data generation apparatus according to claim 1 or 2, characterized in that the propagation calculation means calculates the complex amplitude distribution of the hologram surface using a GS algorithm.

4. A hologram data generation program for causing a computer to function as a hologram data generation device according to any one of claims 1 to 3.

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