JP3272752B2 - White light reproduction hologram recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white light reproducing hologram recording apparatus for calculating and scanning and recording a white light reproducing hologram pattern.

[0002]

2. Description of the Related Art Computer holograms include those which are created by calculating a diffraction image of an object and those which calculate interference fringes. The former divides the hologram surface into small cells, calculates the diffracted light (expressed by complex amplitude) from the object at a representative point in the cell, and creates an aperture in the cell according to the amplitude and phase values of this value. It is made by providing in.

FIG. 2 shows an example of this type of computer hologram. Reference numeral 21 denotes one cell formed by dividing a hologram surface into several parts, and reference numeral 22 denotes an opening in the cell. The height W of the opening 22 is determined according to the amplitude value, and the phase φ
The distance P between the center of the opening 22 and the center of the cell 21 is determined according to the value of. The hatched portion 23 is opaque. Such cells 21 are assembled to form a computer hologram, and the object light can be reproduced by irradiating coherent light (AWLohmann & DPParis:
“Binary Fraunhofer holograms, generated by cmpute
r ”, Appl. Opt., Vol. 6, No. 10, pp. 1739-1748 (Oct. 1
967)).

On the other hand, the latter type of computer hologram for calculating interference fringes, like an optical hologram,
It is created by superimposing a diffraction image of an object on a reference light and determining the transmittance of the hologram cell according to the intensity of the interference fringes of the two. In the former type of computer hologram,
In many cases, the center of the aperture in the cell and the position of the representative point for which the phase is calculated are shifted, resulting in a poorer image quality than a reproduced image obtained from an optically produced hologram. Is expressed in the form of interference fringes, so that a reproduced image with good image quality without a phase error can be obtained.

[0005] Such a conventional type of computer hologram does not require an optical system or an anti-vibration device as compared with an optical hologram formed by interfering a coherent light beam. There are advantages such as making a hologram of an object. However, on the other hand, it takes a lot of time to calculate the diffraction image, and a huge memory is required to store the hologram data. Therefore, it is difficult to create a hologram capable of reproducing a three-dimensional image or a type of hologram capable of reproducing white light. In addition, there is a disadvantage that the image quality is poor, and further, a procedure for reducing the hologram is required for reproduction.

[0006]

As described above, in the conventional computer hologram, the calculation efficiency is low (the calculation time is long and the amount of memory is large), the image quality is poor (there is a phase error, the reproduction of white light is not good). It is difficult to reproduce a three-dimensional image), and it is necessary to reduce the hologram by photographic technology.

The present invention makes it possible to shorten the calculation time and save the memory while utilizing the advantages of computer holograms, such as simple equipment and the ability to create holograms of imaginary objects other than real objects (or CG images). Accordingly, an object of the present invention is to provide a white light reproduction hologram pattern recording apparatus capable of increasing the calculation efficiency and obtaining a three-dimensional reproduction image with excellent image quality and a reproduction image using white light.

[0008]

In order to solve the above-mentioned problems, a white light reproducing hologram recording apparatus according to the present invention has the following features.
Diffraction pattern of a three-dimensional object or
A real image of the three-dimensional object from a first interference fringe pattern with illumination
And a real image calculating means for calculating
The calculated real image is defined as the object light, and the distance between this object light and the reference light is calculated.
Fringe pattern calculation for calculating a second interference fringe pattern
Means for scanning and recording the second interference fringe pattern on a recording medium.
Scanning recording means .

According to the present invention, a set of one or a plurality of scanning lines is set as one block in scan printing, and a procedure of performing scan printing in accordance with an interference fringe pattern of a portion corresponding to one block is repeated for each block. Alternatively, the procedure is performed in parallel with a plurality of blocks to scan and record the entire interference fringe pattern. In this case, it is preferable that the calculation of the interference fringe pattern of one block and the scanning printing are performed in parallel.

Further, the present invention provides a method for calculating a real image .
From the real image reproducible partial pattern of the interference fringe pattern of No. 2 to 3
It is characterized in that a real image of a three-dimensional object is calculated.

A thin slit is provided when a real image of a three-dimensional object is reproduced from a second interference fringe pattern of the diffraction image pattern and the reference light or a pattern of a real image reproducible portion thereof , and the slit portion is provided. It is desirable to use a reconstructed real image calculated from only the above data. In this case, in the calculation of the second interference fringe pattern used for reproducing the real image or the real image reproducible part thereof , if the incident angle of the diffraction image and the incident angle of the reference light are made equal, the interference fringe pattern or the interference fringe pattern can be obtained. The sample density required for the real image reproducible part can be reduced.

Also, a three-dimensional object beam (referred to as one line of three-dimensional object light) parallel to the slit and coming from a direction of a certain angle (elevation angle) from the position of the slit used for reproducing the real image is generated at the slit position. An interference fringe pattern of one block can be scanned and recorded by using an interference fringe pattern of the pattern or diffraction image pattern and the reference light or a reproduced real image calculated from a real image reproducible portion of the interference fringe pattern.

A fixed angular direction from the slit position is discretized, and one line of three-dimensional object light obtained from the discretized angular direction and one block of one line calculated from one line of three-dimensional object light. It is desirable that the positional relationships of the interference fringe patterns correspond to each other.

[0014]

[0015]

[Function] A hologram created by superimposing a real image of an object and a reference beam is a hologram of a type that can be reproduced with white light. If scanning recording is performed using a laser beam that is narrowed down, direct recording of the hologram becomes possible. Time reduction processing can be omitted. That is, it is not necessary to reduce the hologram at the time of reproduction, and a hologram capable of white light reproduction and three-dimensional reproduction can be produced.

In the real image reproduction, not a high-resolution hologram in which the angle between the diffracted light and the reference light is large, but a diffraction image pattern with a relatively low resolution or an interference fringe in which the angle between the diffracted light and the reference light is in the same direction. By using a pattern (hologram pattern), calculation time can be reduced and memory can be saved.

Further, in scan printing, only one line or an interference fringe pattern corresponding to one block in which several lines are put together is calculated and scanning printing is performed, so that memory can be saved, and one line or one block can be saved. By performing the calculation of the interference fringe pattern and the scan recording in parallel, the time required for producing the hologram can be reduced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram of an image hologram production system shown as a basic embodiment of a hologram recording apparatus of the present invention, and shows a three-dimensional object 1 to be displayed as a hologram.
A first real image calculation unit 12, the reference beam 1 to the real image object light
8 and the interference fringe pattern (second interference fringe pattern
And a scan recording unit 19 for scanning and recording on a recording medium such as a photosensitive agent using a laser beam narrowed down in accordance with the intensity of the second interference fringe pattern.
Consisting of Further, the real image calculation portion 12 and the diffraction image calculation unit 13 for calculating a diffraction image pattern of a three-dimensional object, the diffracted
Were added interference Watarushima pattern reference beam 15 on the image pattern (first
Hologram calculating unit 14 for calculating the interference fringe pattern)
And a real image reproducing unit 16 for reproducing a real image from the second interference fringe pattern . As a method of reproducing a real image, there is a method of calculating based on an image forming mechanism of a lens. In this embodiment, a method using a method of reproducing a real image from a hologram will be described.

A hologram used when a real image is reproduced by an optical system, forms interference fringes by superposing object light from a three-dimensional object and reference light such as a plane wave or a spherical wave, and exposing the photosensitive agent to a hologram. . In this case, the hologram needs to be made with a large difference between the incident angle of the object light and the incident angle of the reference light on the hologram surface in order to effectively separate the virtual image and the real image generated when reproduced by the laser light. . As a result, the resolution of the hologram pattern becomes very high. When the process of reproducing the real image is realized by calculation, if the process in the optical system is performed as it is, the efficiency becomes extremely poor in terms of calculation time and memory amount.

Therefore, in this embodiment, the real image is reproduced from a hologram having a low resolution to improve the efficiency. That is, after the diffraction image pattern of the three-dimensional object is calculated by the diffraction image calculation unit 13, the hologram calculation unit 14 superimposes the reference light 15 from the same direction as the diffraction image pattern and calculates the hologram pattern. Only the components (real image components) to be calculated are calculated, and the real image reproducing unit 16 reproduces a real image from the real image components. The pattern of the real image component is represented by a complex amplitude, and the resolution is considerably reduced compared to the hologram pattern of the optical system. Therefore, the memory amount is considerably reduced, and the calculation time is also significantly reduced. The object light on the hologram surface is O (x, y), and the reference light is R (x, y)
When the hologram pattern I (x, y) is I (x, y) = | O (x, y) + R (x, y) | 2 = | O (x, y) | 2 + | R (x, y) ² + O (x, y) R (x, y) ^* + O (x, y) ^* R (x, y) (1), of which the fourth term is a real image reproduction component. *
Means complex conjugate. Another possible real image reconstruction method is a diffraction image pattern (complex amplitude) before calculating interference fringes.
Can be used to reproduce a real image. In this case, the memory amount can be reduced and the calculation time can be reduced. The above-described method of calculating the diffraction image pattern and the method of calculating the real image reproduction have already been formalized (these are detailed in optical reference books and literature). For example, taking a case where a Fresnel hologram is calculated using a two-dimensional image as an object, Fresnel diffraction image data can be obtained by the following algorithm.

(1) A two-dimensional image is represented by sample values.
The sample density is affected by the performance of the hologram creation system and the image quality required for the reproduced image from the hologram, but about 8 to 10 lines / mm is sufficient to obtain a high-quality reproduced image. Would.

(2) Calculate a Fresnel diffraction image pattern (two-dimensional) formed on the hologram surface by light emitted from each sample point. This calculation may be thought of as calculating the wavefront of light emitted from the point light source, or assuming that there is a minute aperture at the position of the sample point, and irradiating a plane wave having an intensity equivalent to the sample value from behind the aperture. It may be considered to calculate the wavefront of light from the minute aperture at the time, and a two-dimensional Fresnel diffraction image is obtained from each sample point. Fresnel integration is used for these calculations (the details are given in reference books on optics and in the literature).

(3) Finally, if all Fresnel diffraction image patterns from each sample point are added together, a Fresnel diffraction image pattern for a two-dimensional object can be obtained.

The Fresnel diffraction image pattern of a three-dimensional object is expressed in a three-dimensional space in the same manner as in the case of a two-dimensional object (sample value is assigned to each point of a three-dimensional grid) or the three-dimensional object surface is What is necessary is to express sample values and add Fresnel diffraction image patterns from each sample point. At this time, it is also possible to perform hidden surface removal. The diffraction image calculation unit 13 may perform the Fresnel transformation of the above method, and when calculating the real image from the real image component of the hologram,
Fresnel conversion of this real image component may be performed (when the incident angle of the object light and the reference light is different, a signal obtained by multiplying the real image component by reproduction light in the opposite direction to the reference light may be subjected to Fresnel conversion). When a real image is reproduced from a diffraction image pattern, Fresnel conversion is performed after the phase of the diffraction image pattern is inverted.

The real image reproduced in this manner is projected onto the hologram surface of the hologram calculation unit 17, the interference fringe pattern is calculated by superimposing the actual image on the hologram calculation unit 17, and then scanning and recording is performed by the laser scanning and recording unit 19. Basically, an image hologram capable of reproducing white light can be produced.

There are two considerations in calculating the interference fringe pattern in the hologram calculation units 14 and 17. The first point is three kinds of signals (object, diffraction image, interference fringe)
The different sample densities required to represent each are different. For example, a sample density of about 8 to 10 lines / mm is sufficient for expressing an object, but it is sufficient for a diffraction image pattern to be about several tens to 100 lines / mm, and for an interference fringe pattern, at least several hundred lines / mm. (More than 1000 / mm in some cases) is required, and the sample density varies considerably. Ultimately, a calculated value at the density of the interference fringe pattern is required. However, if all calculations are performed at this density, a huge amount of memory is required, which is inconvenient.

The second point is that the calculation of the diffraction image pattern takes a considerable amount of time. In such a situation, in order to minimize the calculation time and the required memory amount, calculation is performed with the sample density of the diffraction image pattern as small as possible, and the sample value of the diffraction image pattern is interpolated (linear density conversion). If the interference fringe pattern is calculated while increasing the sample density of the interference fringe pattern, the amount of time required to calculate the diffraction image pattern, that is, the calculation time, is reduced, and the memory amount is reduced.

Therefore, in the hologram apparatus of this embodiment, the diffraction image pattern is calculated at a sample density of about several tens / mm, and when calculating the interference fringe pattern, the sample points of the diffraction image pattern for two lines are calculated. Then, the data between sample points is interpolated to increase the required density by interpolating the data, and is superimposed on the reference light to obtain a final interference fringe pattern and scan and record the pattern. As a result, it is possible to realize a system capable of reducing calculation time and saving memory without storing an interference fringe pattern having a high sample point density.

Next, the sample value interpolation of the diffraction image pattern will be described. Interpolation processing is processing for matching the sampling density of diffraction image data with the sampling density of interference image data to be finally recorded, and is basically the same processing as the linear density conversion processing performed in general image processing. . Here, a case is considered in which a line memory for two lines is provided and two-dimensional interpolation processing is performed by electronic processing for both main scanning and sub-scanning.

FIG. 3 shows a diffraction image pattern for two lines and two diffraction image patterns.
It is an example illustrating a procedure of a dimension interpolation processing method. The white circles represent the i-th and (i + 1) -th sample points of the diffraction image pattern, and are data obtained by interpolating black triangles and black squares. In the case of interpolation, first, an interpolation point (indicated by a black square) in the main scanning direction is determined using the sample point of the i-th line (an example of three-point interpolation), and its value is calculated to calculate the interference fringe pattern. One line of diffraction image data required for calculation is constructed. The interference fringe data for one scanning line is calculated from the diffraction image data for one line, and the diffraction image pattern corresponding to the next scanning line is calculated after or while performing the scanning recording. The diffraction image data corresponding to the next scanning line is i
An interpolation point (indicated by a black triangle) is determined in the sub-scanning direction between the two lines at the positions of the sample points (white circles) of the i-th diffraction image line and the (i + 1) -th diffraction image line (example of three-point interpolation) , The value of the interpolation point closest to the i-th diffraction image line that has already been scanned and recorded. Then, an interpolation point (indicated by a black square) in the main scanning direction is determined (an example of three-point interpolation), and its sample value is calculated and executed, whereby diffraction image data for the next scanning line is obtained. If this procedure is continued up to the (i + 1) th diffraction image line, 2
The dimensional interpolation is completed. This process is repeated for all diffraction image lines. The interpolation processing in this description is basically one-dimensional interpolation, and conventional interpolation processing such as simple linear interpolation, Lagrange interpolation, and spline interpolation can be used, but the processing for interpolating data is not limited to these methods. It goes without saying that anything is fine.

Furthermore, in this description, an example has been described in which interpolation processing is performed using two lines, but it is also possible to use more lines.

The calculation method of the interference fringe pattern obtained by superimposing the interpolated diffraction image data and the reference light (plane wave or spherical wave) is as follows. Diffraction image pattern 2
Diffraction image data with high resolution for each scanning line (meaning one line of an interference fringe pattern to be scanned and recorded, not one line of a diffraction image pattern) obtained by interpolation processing using data for a line, and a plane wave or Reference light 18 of spherical wave
Is independently added at each sample point, and the absolute value is squared. As a specific calculation method, an interference fringe pattern is obtained by multiplying the real part and the imaginary part of the interpolated diffraction image data and the reference light data by each, and adding the multiplication results. Since the amplitude of this interference fringe pattern also fluctuates in the negative direction, after multiplying the interference fringe data by an appropriate constant to adjust the amplitude value of the interference fringe pattern, the bias fringe pattern is further added by adding a bias constant. Have only positive amplitude values. This is because only a positive value can be recorded when scanning and recording on a recording medium.

As described above, the interference fringe pattern for one scanning line can be calculated. The interference fringe pattern of the next scanning line can also be calculated by repeating the same processing from the interpolated diffraction image data corresponding to this scanning line position.

The interference fringe data for one scanning line obtained from the hologram calculation unit 17 is recorded on a recording medium by the laser scanning recording unit 19. At this time, in order to correct the gradation characteristics of the exposure characteristics of the recording material and the modulation characteristics of the recording light source, and to suppress noise generation due to distortion of the gradation characteristics of the finally generated interference fringe pattern, the gradation correction is performed. It is desirable to perform the processing. In the conventional optical interferometry, control of gradation is difficult due to the characteristics of the recording material itself. However, the gradation correction processing according to the present invention is easy to control, and is important for high image quality. There are benefits.

The corrected interference image data subjected to the gradation correction is
The data is written on the recording material by the scanning recording unit 19. To create an interference fringe type hologram, 1000 lines / mm
To 3000 lines / mm in some cases. Here, FIG. 4 shows the configuration of a rotary drum type scanning system and a scanning recording unit 19 which is multi-beamed to increase the recording speed.

In FIG. 4, a recording material is mounted on a drum 100. Drum 100 is a drum rotation drive motor 1
01 rotates at a constant speed. This rotation direction X corresponds to the main scanning direction. The rotation state of the drum 100 is monitored by a rotary encoder 102 attached to the rotation shaft.
04, which is further sent to the clock control circuit 105 and fed back to the write timing of the recording data.

On the other hand, the sub-scan is performed by moving the recording light source. Three LDs (semiconductor lasers) 107, 108, and 109 are attached to the recording light source unit 106 at intervals.
At 1,112, the spot size on the recording surface is narrowed down to approximately the wavelength order. The interval between the LDs 107 to 109 is a value obtained by dividing the recording width in the sub-scanning direction Y into three equal parts, and is basically adjusted so as to satisfy a positive multiple of the scanning line pitch. Should be satisfied. The recording light source unit 106 is moved and scanned in the sub-scanning direction Y by a ball screw 113 and a light source driving motor 114 that rotates the ball screw 113. Thus, the scanning is completed at a moving distance of 1/3 of the entire recording width in the sub-scanning direction Y.

The drum rotation driving motor 101 corresponding to the main scanning and the light source driving motor 114 corresponding to the sub-scanning
Are driven by motor drive circuits 115 and 116, respectively. In this drive control, control synchronized with a control signal from the control circuit 117 and a clock from the clock control circuit 104 is performed.

The corrected interference image data to be recorded is inputted to the buffer circuit 118 in three channels in parallel. The print data captured by the buffer circuit 118 is converted into the digital-to-analog converter 11 in accordance with the scanning drive timing.
9 This digital-to-analog converter 119
The recording data signal converted into an analog signal in parallel with the channel is supplied to the light source array driving circuit 120, whereby the light intensity of each of the LDs 107 to 109 is modulated, and a two-dimensional interference image pattern is formed in combination with the multi-beam scanning. The key is recorded. The recording control unit 121 controls the entire multi-beam scanning recording in response to an instruction from the host control unit.

Thus, the recording of the hologram is completed. The written recording material is subjected to processing such as development and fixing as necessary, and a final hologram is completed.
The configuration of the processing of this recording material differs depending on the recording material to be used.
It is better not to need recording material processing for performing processing such as development and fixing. For example, if a photochromic using photochemical change, an electro-optical material such as LiNbO ₃ whose refractive index is changed by light, or an amorphous semiconductor whose refractive index changes with light blackening is used, no recording material treatment is required.
Recording materials that can be handled by a relatively simple dry process include thermo plastics used in electrostatic recording and thermal development.
Photopolymers (monomers, initiators,
Polymer matrix type containing a sensitizing dye).
Silver salt photosensitive materials, dichromated gelatin, photoresists, and the like, which have been often used in the past, require a wet process, but there is no problem from the viewpoint of the present invention as long as they can be incorporated in an apparatus or system.

(Embodiment 2) FIG. 5 shows an embodiment in which the present invention is applied to a rainbow hologram. In the real image calculation unit 12, a direction designation unit 3 for diffracted light is provided at a stage preceding the diffraction image calculation unit 13.
1 is different from the first embodiment. The hologram of this type has a parallax in only one direction because a real image is reproduced from interference fringes in a narrow slit portion.
It is characterized by less blurring and better image quality than the image hologram of the above.

In order to make a rainbow hologram by an optical method, a method of once making a hologram by an ordinary method, providing a thin slit in the hologram, reproducing a real image from the slit portion, and then converting the reproduced real image into a hologram again. General. When you calculate according to this procedure,
It is clear that the computation time and the amount of memory are extremely inefficient. Therefore, in this embodiment, the calculation efficiency is improved by utilizing the fact that the finally obtained hologram basically has parallax in only one direction. That is, the hologram used for reproducing the real image by the direction designation unit 31 of the diffracted light in the real image calculation unit 12 may be a hologram having only one-way parallax, and may be calculated for each line. A specific calculation method when a two-dimensional plane is used as an object will be described below.

(1) One line (parallel to the slit) that intersects the two-dimensional object plane when a light beam emitted from the slit at a constant angle (elevation angle) and parallel to the slit from the position of the slit is determined.

(2) Calculate a diffraction image pattern, an interference fringe pattern, or a real image reproducible portion of the interference fringe pattern generated by one line of the two-dimensional object plane at the slit position. Since this calculation is only for one line, the diffraction image with this method has a smaller resolution than the calculation of the diffraction image pattern as the sum of the diffracted light reaching the slit position from the entire object as in the case of the optical method. Calculation of patterns is allowed.
Further, if the direction of the reference light used for calculating the interference fringes is the same as the direction of the object light for one line, the calculation of the interference fringe pattern can be performed with a small resolution, so that the calculation can be performed with a short calculation time and a small memory amount.

(3) One line of real image is reproduced from the diffraction image pattern or interference fringe pattern of the slit portion or the real image reproducible portion of the interference fringe.

(4) Interpolate the reproduced real image for one line,
After increasing the sample density to the resolution required for the interference fringe pattern, superimposing the reference beam, calculating the interference fringe pattern,
Perform laser scanning recording. Normally, a plane wave is often used as the reference light. The number of scanning lines obtained at this time depends on the angle of incidence of the plane wave of the reference light. For example, when the incident angle of the plane wave is in the vertical direction (parallel to the slit), interference fringes are formed in the vertical direction, so that it is necessary to record many scanning lines. That is, the object image corresponding to the width of one line is
This produces many scan lines in the same width. On the other hand, when the incident angle of the plane wave is set in the left-right direction (perpendicular to the slit), 1
One scanning line can fill the width of one line.

(5) A fixed angle (elevation angle) from the slit position
Is changed, and the calculations from (1) to (4) are repeated to complete the rainbow hologram. How to change the elevation value
The angles may be discretized at equal intervals, or unequal intervals may be obtained by changing the discretization angle between a large angle portion and a small angle portion. Alternatively, the elevation angle may be determined so that the width of the object image for one line is fixed, instead of being discretized by the angle. A discretization density of about 8 to 10 lines / mm is sufficient.

In the above description, a two-dimensional image is taken as an example of an object. However, a three-dimensional object can be calculated in exactly the same manner.

(Embodiment 3) FIG. 6 shows an embodiment in which the present invention is applied to a holographic stereogram. A parallax image calculating section 30 is inserted before a real image reproducing section 30. Image switching unit 32 and real image adding unit 3
3 has been added. First, various angles for observing the three-dimensional object are changed, and a two-dimensional image (referred to as a parallax image) at each angle is calculated by the parallax image calculation unit 30. This is the same as taking a picture at a different angle. Next, as in the second embodiment, from one line of the first parallax image corresponding to the elevation angle direction from the slit position,
Calculate the real image reproducible part of the diffraction image pattern or interference fringe pattern or interference fringe pattern at the slit position,
The real image is reproduced. The calculation method at this time is the same as that of the second embodiment. Next, a real image is reproduced in the same manner using the second parallax image and added to the first real image. If this process is performed on all parallax images, a real image of a three-dimensional object can be obtained.

In the example of FIG. 6, the addition is performed at the stage of the reproduced real image in the real image adder 33. After reconstructing a diffraction image pattern or an interference fringe pattern corresponding to one line or a real image reproducible portion of the interference fringe pattern, the real image may be reproduced.

Finally, an interference fringe pattern is calculated by adding a reference beam, and scanning and recording for one line may be performed. In this procedure, the direction (elevation angle) of the diffracted light is determined by the diffracted light direction designation unit 31.
Is changed and repeated.

In the above embodiment, the number of slits is not limited to one, and if a plurality of slits are used, parallax is generated not only in the horizontal direction but also in the vertical direction. In order to color the hologram, the calculation procedures of Examples 1 to 3 are performed using three wavelengths of red, blue, and green, and the respective interference fringe patterns are superimposed on a recording medium capable of recording a three-color signal. What is necessary is just to scan and record together.

[0053]

As described above, according to the present invention, the computation time can be reduced and the amount of memory can be reduced while taking advantage of the characteristics of a conventional computer hologram such as the ability to create a hologram of an imaginary object without the need for a complicated optical system. It is possible to improve the calculation efficiency by saving the image and to create a hologram capable of reproducing white light of a three-dimensional object having excellent image quality.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment in which a hologram recording device of the present invention is applied to an image hologram.

FIG. 2 is a diagram for explaining the relationship between cells and openings in a conventional computer hologram pattern;

FIG. 3 is an explanatory diagram of an interpolation process in the embodiment.

FIG. 4 is a diagram showing a configuration example of a scanning recording apparatus in the embodiment.

FIG. 5 is a block diagram showing an embodiment in which the hologram recording device of the present invention is applied to a rainbow hologram.

FIG. 6 is a block diagram showing an embodiment in which the hologram recording device of the present invention is applied to a holographic stereogram.

[Explanation of symbols]

REFERENCE SIGNS LIST 11 three-dimensional object 12 real image calculation unit 13 diffraction image calculation unit 14 hologram calculation unit 15 reference light 16 real image reproduction unit 17 hologram calculation unit 18 reference light 19 laser scanning recording device 21 cell 22 Aperture 23 ... Opacity part 30 ... Parallax image calculation unit 31 ... Diffraction light direction designation unit 32 ... Parallax image switching unit 33 ... Real image addition unit 106 ... Recording light source unit 107-10
9 Semiconductor laser 110-112 Focusing lens 113 Ball screw

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-71078 (JP, A) JP-A-59-69775 (JP, A) Hiroyuki Nagai One other person, Generalization and application of Fourier transform computational hologram Physics, Japan, November 10, 1976, Vol. 45, No. 11, p. 1033-1038 (58) Field surveyed (Int.Cl. ⁷ , DB name) G03H 1/00-5/00

Claims (3)

(57) [Claims] 1. A diffraction image pattern of a three-dimensional object or said diffraction pattern
From the first interference fringe pattern between the image pattern and the reference light,
A real image calculating means for calculating the real image dimension object, a real image calculated by said real image calculating means and the object beam,
An interference fringe pattern calculating unit for calculating a second interference fringe pattern between the object light and the reference light; and a scanning recording unit for scanning and recording the second interference fringe pattern on a recording medium. White light reproduction hologram recording device. 2. The method according to claim 1, wherein the scanning recording means sets a set of one or a plurality of scanning lines of the scanning recording as one block and performs a scanning recording procedure according to an interference fringe pattern of a portion corresponding to one block. 2. The white light reproduction hologram recording apparatus according to claim 1, wherein the whole interference fringe pattern is scanned and recorded by repeating or executing the procedure in a plurality of blocks in parallel. Wherein the real image calculating means, the first interference Shimapa
2. The hologram recording apparatus for white light reproduction according to claim 1, wherein a real image of the three-dimensional object is calculated from a pattern of a real image reproducible portion of a turn .