JP2006084526A - Hologram reproduction device and hologram reproduction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a bright reproduced image free from deterioration in the whole screen even when an image except an image bright only in a part of a reproduced image can not be obtained though the incident angle of reproduction illumination light to a recording material is finely adjusted to a change in the volume of the recording material. <P>SOLUTION: When the change in the volume and the change on the refractive index in a hologram recording material are generated during hologram recording and when one defectless reproduced image can not be obtained even if the angle of reproduction illumination light is changed and the closest state where a Bragg condition is satisfied is made, the position on the recording material of the reproduction illumination light is changed while the incident angle at this time is held, and reproduced images 51, 52, 53 are acquired on the same page. Then, the satisfactory parts in these images are connected by image composition, so that one defectless satisfactory reproduced image 54 is obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hologram reproducing apparatus that reproduces a hologram volume-recorded on a hologram recording material (hologram recording medium), and more particularly to a hologram reproducing method that corrects and reproduces the shrinkage of the recording material during hologram recording.

  In recent years, a hologram recording / reproducing system for recording / reproducing large-capacity data using hologram technology has been proposed. This hologram recording / reproducing system, for example, generates a hologram recording material (with a predetermined angle) between a signal light including recording data generated by a spatial light modulator such as a liquid crystal element and a reference light set corresponding to the signal light. The recording system records the interference fringes generated by the signal light and the reference light on the recording material, and the hologram recording material is irradiated with the reproduction illumination light. In this configuration, diffracted light (reproduced signal light) corresponding to the interference fringes is generated, received by a light receiving element such as a CCD image sensor, and analyzed to reproduce the data. A hologram per spatial light modulator recorded in this way is called a page.

  In the hologram recording / reproducing system, a technique called multiple recording is used to improve the recording density. This is different from recording on a conventional optical disc in that a large number of independent pages are recorded in one place. Typical examples of such multiplex recording methods are angle multiplex recording, shift multiplex recording, phase code multiplex recording, and many other multiplex methods are known.

  The angle multiplexing method records and reproduces a large number of independent pages in one place by changing the angle of the reference beam. Shift multiplex performs multiplex recording by shifting the recording position little by little. In phase code multiplexing, when one page is recorded, recording is performed by simultaneously applying reference light from various directions. However, at that time, a phase change is given to the reference light from each direction. By combining this phase change in various ways, a large number of independent pages are recorded and reproduced in one place. In addition to the above three types, many multiplexing schemes such as speckle multiplexing are known.

  By the way, it is known that a hologram recording material, particularly a photopolymer material, undergoes a volume change during or after recording due to a chemical reaction of the photosensitive material, and as a result, a reproduced image is deteriorated (for example, non-photosensitive material). Patent Document 1). As an example of the volume change after recording, recording and reproduction of a hologram formed by two parallel beams will be described with reference to FIGS.

  FIG. 7 is a diagram illustrating a case where the recording material has no volume change. As shown in FIG. 7A, the interference fringes 30 of the signal light 100 and the reference light 200 are volume-recorded on the recording material 20. In FIG. 7A, the interference fringes are displayed as parallel light. However, since the signal light is not actually parallel light, the recorded interference fringe does not become parallel light. When there is no volume change, there is no change in the recorded interference fringe 30 as shown in FIG. 7B, and if the reproduction illumination light 200 ′ is incident at the same angle as the reference light 200 at the time of recording, the desired direction is obtained. The reproduction signal light 300 can be obtained.

However, when there is a volume change as shown in FIG. 8, the interference fringes 30 recorded on the recording material 20 as shown in FIG. 8 (A) are shrunk (reduced) by the recording material 20 as shown in FIG. 8 (B). It changes as shown. When the reproduction illumination light 200 ′ is incident on the recording material 20 thus changed at the same angle as the reference light 200 at the time of recording, the Bragg condition with the interference fringes recorded on the recording material 20 is not satisfied, and the reproduction signal The light 300 becomes dark and in some cases cannot be reproduced. In such a case, in order to obtain the bright reproduction signal light 300 by correcting the volume change of the recording material 20, it is necessary to change the angle of the reproduction illumination light 200 ′.
(For example, non-patent literature: Holographic Data Storage; HJCoufal, D.Psaltis, GTSincerbox ED; Springer; p.185 Photopolymer System)

  In the angle multiplexing system as described above, bright reproduction signal light can be obtained by correcting the volume change of the recording material by approximately satisfying the Bragg condition by changing the incident angle of the reference light during recording and reproduction. Can do. However, since the signal light 100 has an angle of view, even if the incident angle of the reproduction illumination light is finely adjusted as described above when the volume of the recording material changes, the interference fringes in which the Bragg conditions are recorded The angle of view is not equally satisfied, and the brightness of the reproduced image is non-uniform as shown in FIG. 9B with respect to the recorded image shown in FIG. It only brightens to satisfy the Bragg condition. Therefore, how to correct the volume change of the recording material 20 in such a case becomes a problem.

  The present invention has been devised in view of the above circumstances, and the object of the present invention is to provide only a part of a reproduced image even if the incident angle of the reproduction illumination light to the recording material is finely adjusted with respect to the volume change of the recording material. An object of the present invention is to provide a hologram reproducing method and a hologram reproducing apparatus capable of obtaining a bright reproduced image having no deterioration on the entire screen even when a bright image cannot be obtained.

  In order to achieve the above object, the present invention provides a hologram reproducing apparatus that obtains a reproduced image by irradiating a hologram recording material with reproduction illumination light, and the position at which the reproduction illumination light is irradiated onto the hologram recording material is the reproduction illumination at that time. Position changing means for changing while maintaining the incident angle of light, and image acquisition means for acquiring a plurality of reproduced images of the same page reproduced from the hologram recording material each time the irradiation position of the reproduction illumination light is changed Determining means for determining a predetermined characteristic portion of the acquired reproduction image for each of the irradiation positions; image cutting means for cutting out a predetermined characteristic portion of the reproduction image for each of the determined irradiation positions; And image synthesizing means for synthesizing predetermined characteristic portions of the reproduced image into a single reproduced image.

  Further, the present invention is a hologram reproducing apparatus for obtaining a reproduced image by irradiating a reproduction illumination light onto a hologram recording material, wherein the relationship between the irradiation position of the hologram recording material of the reproduction illumination light and a predetermined characteristic partial position of the reproduced image Storage means for preliminarily storing data indicating position, position changing means for changing the position at which the reproduction illumination light is irradiated onto the hologram recording material while maintaining the incident angle of the reproduction illumination light at that time, and the reproduction illumination light Image acquisition means for acquiring a plurality of reproduced images of the same page reproduced from the hologram recording material each time the irradiation position is changed, and a predetermined characteristic portion of the acquired reproduced image for each irradiation position is stored in the memory Image cutting means for cutting out based on the extracted data, and image combining means for combining the predetermined characteristic portions of the clipped reproduction image into a single reproduction image Characterized in that it Bei.

  As described above, in the present invention, when the hologram recording material undergoes a volume change and a refractive index change during hologram recording, the incident angle or irradiation position of the reproduction illumination light to the hologram recording material is changed to satisfy the Bragg condition. If a single reconstructed image without defects cannot be obtained even in the closest state, a plurality of sheets on the same page can be obtained by changing the irradiation position of the reproduction illumination light onto the hologram recording material while maintaining the incident angle at that time. By collecting good images of these multiple images and synthesizing a single bright image without defects, the incident angle of the reproduction illumination light with respect to the recording material against the volume change of the recording material can be adjusted. Even when a fine image can be obtained by only a part of the reproduced image even if fine adjustment is performed, a bright reproduced image with no deterioration can be obtained on the entire screen.

  According to the present invention, a plurality of images on the same page are obtained by changing the irradiation position of the reproduction illumination light onto the hologram recording material while maintaining the incident angle at that time, and good portions of the plurality of images are obtained. By collecting and synthesizing a bright image without a single defect, even if the incident angle of the reproduction illumination light with respect to the recording material is finely adjusted with respect to the volume change of the recording material, only a part of the reproduced image is bright. Even in this case, it is possible to obtain a bright reproduced image without deterioration on the entire screen.

  The purpose is to obtain a bright reproduced image with no deterioration on the entire screen even when a bright image is obtained only in a part of the reproduced image even if the incident angle of the reproducing illumination light to the recording material is finely adjusted with respect to the volume change of the recording material. By changing the irradiation position of the reproduction illumination light onto the hologram recording material while maintaining the incident angle at that time, a plurality of images of the same page are obtained, and good portions of these images are collected to obtain a single sheet. Realized by synthesizing bright images without defects.

FIG. 1 is a block diagram showing a configuration of a hologram reproducing apparatus according to an embodiment of the present invention. The hologram reproducing apparatus performs hologram recording by a shift multiplexing method, and includes a laser light source 1, a polarizing beam splitter 2, a mirror 3, a Fourier lens 4, a mirror 5, a spatial light modulator 6, a Fourier lens 7, a hologram recording material 8, and an inverse Fourier lens. 9, an imaging device 10, a spindle motor 11, an actuator 12, and a control device 13 such as a personal computer.
In addition to the normal shift multiplex control, the control device 13 minutely changes the position of the reproduction illumination light while maintaining the incident angle. Each time the reproduction illumination light is minutely changed, a plurality of images of the same page are obtained. It is assumed that control is performed such as obtaining, extracting and cutting out predetermined characteristic portions of these acquired images, and combining the obtained predetermined characteristic portions into a single image to form a reproduced image.

  FIG. 2 is a block diagram showing a detailed configuration example of the control device shown in FIG. The control device 13 includes a CPU 201, a memory 202, an image processing unit 203, an image memory 204, an interface 205, and an interface 206. The interface 205 connects the imaging device 10 shown in FIG. 1, and the interface 206 connects the actuator 12. is doing. The CPU 201 controls the movement of the reference light optical system through the interface 206 and inputs reproduced image data from the imaging apparatus 10 into the apparatus through the interface 205.

  Next, the operation of the present embodiment will be described. At the time of recording, the data page to be recorded is displayed on the spatial light modulator (transmissive liquid crystal display device) 6, and then the coherent laser light emitted from the laser light source 1 is incident on the polarization beam splitter 2 and recorded. The light 100 and the reference light 200 are branched. The recording light 100 is incident on the spatial light modulator 6 via the mirror 5. The recording light 100 undergoes spatial light modulation (intensity modulation) by passing through the spatial light modulator 6 on which the data page is displayed. The modulated recording light 100 is condensed on the recording area of the hologram recording material 8 by the Fourier lens 7. On the other hand, after the traveling direction of the reference light 200 is changed by the mirror 3, the reference light 200 is irradiated by the Fourier lens 4 so as to intersect the recording light 100 and the hologram recording material 8 at a certain angle to generate interference fringes. The data page described above is recorded on the hologram recording material 8 as a refractive index distribution according to the spatial distribution of the interference fringes.

  After recording one hologram, the control device 13 controls the spindle motor 11 to move the hologram recording material 8 by a certain distance relative to the optical system to record the next hologram. In this case, every time one hologram recording material 8 is recorded, the disk-shaped hologram recording material 8 is rotated by a certain angle by the spindle motor 11. When the hologram recording material 8 is rotated once, the optical system or the hologram recording material 8 is moved in the radial direction, and recording in the material circumferential direction is performed again. By repeating the above, a large number of holograms are recorded over the entire surface of the hologram recording material 8.

  When the hologram recorded in this way is reproduced, the hologram recording material 8 is irradiated with reference light (reproduction illumination light) 200 having the same incident angle from the same position as when the hologram was recorded. Thereby, diffracted light corresponding to the interference fringes recorded on the recording track of the hologram recording material 8 is generated, and this diffracted light is condensed and received by the inverse Fourier lens 9 on the image pickup device in the image pickup device 10. The obtained light reception signal is analyzed and becomes the original image data (data page).

  Here, when a volume change or a refractive index change occurs in the hologram recording material 8 during recording, the Bragg condition remains even if the hologram recording material 8 is irradiated with the same reproduction illumination light as the reference light 200 during recording as described above. Since it is not satisfied, the diffraction efficiency decreases and only a dark reproduced image can be obtained. In such a case, the control device 13 performs a series of operations for correcting volume change or refractive index change as described below.

  When the reference beam is not parallel light, such as spherical wave shift multiplex recording, hologram recording material speckle multiplex recording, or phase code multiplex recording, and there is a volume change or refractive index change of the hologram recording material (recording material) As described above, the image quality of the reproduced image deteriorates due to the deviation from the Bragg condition. In order to correct this, conventionally, as shown in FIG. 3 (A), the reproduction illumination light 200 'is performed by a minute change in the incident angle to the hologram recording material 8. However, in the present embodiment, FIG. As shown in FIG. 4, the irradiation position on the hologram recording material 8 of the reproduction illumination light 200 ′ is changed by a minute distance from the time of recording. Thereby, at least a part of the reproduced image can approximately satisfy the Bragg condition. This is because the change in the angle of the reference beam can be equivalently replaced by the position movement.

  This method of moving the position of the reference light is applicable only to the case where the entire reproduced image matches the Bragg condition within an allowable range, and as described above, only a part of the reproduced image matches the Bragg condition. There wasn't. Even in such a case, when the reproduced image is viewed while moving the reproduction illumination light 200 ′, there is a fact that the portion that matches the Bragg condition and is in a good reproduction state also changes with the movement of the reproduction illumination light. The applied method is the correction method of the present invention.

Here, when the recording image displayed on the spatial light modulator 6 as described above is recorded on the hologram recording material 8, when the hologram recording material 8 changes in volume or refractive index, the control device 13 of the present embodiment. Controls the actuator 12 and moves the reference light optical system by a minute distance with respect to the surface direction of the hologram recording material, as shown in FIGS. 4A to 4C, the hologram recording material of the reproduction illumination light 200 ′. The irradiation position on 8 is moved by a minute distance. As a result, the control device 13 obtains reproduced images 31, 32, and 33 as shown in FIGS. 4 (A) to 4 (C) from the imaging device 10. These images have some bright parts 311, 321, and 331 (parts reproduced beautifully as in the original image), but none of them is a complete reproduced image.

  That is, in a shift multiplex hologram having a volume change or refractive index change, only a part of the reproduced image is closest to a state satisfying the Bragg condition and is reproduced as a beautiful image having no defect. If the good reproduced part and the defective part with poor image quality are determined by the image processing of the control device 13 and only the good part is connected, it is possible to obtain a single reproduced image that is entirely good.

  Therefore, the control device 13 acquires a plurality of images that are not partially defective as indicated by 51, 52, and 53 in FIG. A beautiful image with no defects is obtained as shown in FIG.

  That is, the CPU 201 of the control device 13 controls the actuator 12 to move the reference light optical system, thereby changing the position of the reproduction illumination light 200 ′ on the hologram recording material 8 while changing the position on the hologram recording material 8 from the imaging device 10 to a plurality of FIGS. The reproduced images 51 to 53 as shown are acquired and stored in the image memory 204. Thereafter, the CPU 201 takes out the reproduced images in the image memory 204 one by one and sends them to the image processing unit 203. The image processing unit 203 recognizes which part of the reproduced image 51 to 53 is good in image range, and stores the correspondence between the irradiation position of the reproduction illumination light 200 ′ and the good image partial position in the memory 202. Keep it.

  As a method for determining a good portion of a reproduced image by image processing, (1) the brightness or diffraction efficiency of each image portion is determined. (2) The contrast ratio of each image portion is determined. (3) There is a method of determining the noise amount of each image portion. Next, the CPU 201 refers to the recognition result stored in the memory 202, extracts only the good portions of each reproduced image from the image memory 204, and continuously combines these good portions to reproduce a single defect-free reproduction. The image 54 is synthesized.

  At that time, the image processing unit 203 takes out each reproduced image acquired from the image memory 204 in units of columns (width is, for example, one pixel), looks at the diffraction efficiency (or contrast ratio) of the portion, and exceeds a predetermined level. The image range of the diffraction efficiency (or contrast ratio) is cut out as a good image portion, and the cut out good image portion is connected to synthesize one beautiful reproduced image 54 having no defect. Alternatively, a plurality of reproduced images acquired in the image memory 204 are all cut out in units of columns (width is, for example, one pixel), and a reproduced image portion having a diffraction efficiency (or contrast ratio) of a predetermined level or more in the reproduced images in units of columns. May be combined into a single reproduced image 54 without any defects.

  The predetermined level of diffraction efficiency (or contrast ratio) may be a fixed value or may have a different value for each part of the image. For example, although depending on the laser emission mode, basically, the reproduction diffraction efficiency of the reproduction light is good at the center portion of the page depending on the recording state, and the diffraction efficiency and the like are poor at the edge of the page. Therefore, the diffraction efficiency of the predetermined level is set in accordance with a Gaussian distribution that is high for the center portion of the page of the image area divided by the reproduced image row and low for the end portion of the page.

  In this way, a very good reproduced image can be obtained at the center of the page, and the edge of the page is not reproduced as being less than a certain diffraction efficiency. Also, the diffraction efficiency at the center of the page is not always good depending on the laser emission mode. Therefore, if a predetermined level of diffraction efficiency corresponding to the laser mode at the time of recording is set for each column, an image can be reproduced with higher accuracy.

  Incidentally, in the above embodiment, the correspondence between the irradiation position of the reproduction illumination light 200 ′ and the good portion position of the reproduction image at that time is obtained by image processing for each reproduction image (data page). Is not effective for only one reproduced image, and is usually effective for other reproduced images. Therefore, after obtaining the above-described correspondence for one reproduced image, it may be stored in the memory 202 in the apparatus, and a good image portion may be cut out using the correspondence for other reproduced images. In addition, when measuring the above correspondence relationship for the first time, prepare a data page for measurement (a data page with a pattern in which the diffraction efficiency and contrast ratio of each part of the reproduced image can be easily measured), and reproduce this data page. If the above-described correspondence is obtained, the measurement accuracy can be improved.

  According to the present embodiment, when a volume change and a refractive index change occur in the recording material 8 during hologram recording, the closest state that satisfies the Bragg condition by changing the irradiation position of the reproduction illumination light 200 ′ However, when a single reconstructed image without defects cannot be obtained, the irradiation position of the reconstructed illumination light 200 ′ is changed little by little to obtain a plurality of good reconstructed images 51 to 53 that are partially free of defects. Thus, it is possible to obtain a good reproduced image 54 having no defect by connecting the good portions of the reproduced images by image synthesis.

  In this embodiment, an example in which the present invention is applied to a shift multiplex type hologram recording / reproducing apparatus has been described. However, in an angle multiplex method, a speckle multiplex method using a reference light having a random wavefront, or a phase code multiplex method. The same effect can be obtained by applying the present invention.

  Note that the correspondence relationship between the irradiation position of the reproduction illumination light 200 ′ and the good portion position that is clearly reproduced in one reproduction image as shown in FIG. 6 can be obtained theoretically. This correspondence can be stored in the memory 202 of the control device 13 in advance, and the above-described one good reproduced image 54 having no defect can be obtained by using the correspondence data in the memory 202 at the time of hologram reproduction. However, since the amount of change such as temperature change at the time of recording and reproduction enters the theoretical parameter at that time, for example, in the case of temperature, it is necessary to measure the temperature of the hologram recording material 8 at the time of reproduction. If necessary, it is necessary to measure the temperature at the time of recording and record the temperature in the hologram recording material 8.

  In the above embodiment, the position of the reproduction illumination light 200 ′ is moved by moving the reference light optical system. However, the same effect can be obtained by moving the hologram recording material while fixing the reference light optical system. Obtainable.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can implement also with another various form in a concrete structure, a function, an effect | action, and an effect. For example, in the above embodiment, only correction of the reproduced image due to volume change and refractive index change of the recording material has been mentioned. However, for example, reference light (laser light) at the time of recording and reproduction that causes a deviation from the Bragg condition. The method of the above embodiment is also effective for the difference in wavelength of light and the temperature change of the hologram recording material during recording and reproduction, and a plurality of factors that cause deviation from the Bragg condition can be corrected collectively. And a good reproduction image can be obtained.

It is the block diagram which showed the structure of the hologram reproduction apparatus which concerns on one embodiment of this invention. It is the block diagram which showed the detailed structural example of the control apparatus shown in FIG. It is a figure explaining the correction | amendment method which changes not the incident angle on the hologram recording material of reproduction | regeneration illumination light but an irradiation position for a minute distance. It is the figure which showed the example of a reproduction | regeneration image of the same page with respect to the irradiation position on the hologram recording material of reproduction | regeneration illumination light. It is a figure explaining the image processing operation of the control apparatus shown in FIG. FIG. 2 is a diagram illustrating an example of a target reproduction image when an image processing operation of the control device illustrated in FIG. 1 is performed. It is a figure explaining the recording operation and reproducing operation in the conventional hologram recording / reproducing apparatus. It is a figure explaining reproduction | regeneration operation | movement when the volume change or refractive index change has arisen in the recording material with the conventional hologram recording / reproducing apparatus. It is the figure which showed the recorded image and reproduction | regeneration image in case the volume change was in the conventional recording material.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Laser light source, 2 ... Polarizing beam splitter, 3, 5 ... Mirror, 4, 7 ... Fourier lens, 6 ... Spatial light modulator, 8 ... Hologram recording material, 9 ... Inverse Fourier lens, DESCRIPTION OF SYMBOLS 10 ... Imaging device, 11 ... Spindle motor, 12 ... Actuator, 13 ... Control apparatus.

Claims (15)

A hologram reproducing device that obtains a reproduced image by irradiating the hologram recording material with reproduction illumination light,
Position changing means for changing the position of irradiating the hologram recording material with the reproduction illumination light while maintaining the incident angle of the reproduction illumination light at that time;
Image acquisition means for acquiring a plurality of reproduced images of the same page reproduced from the hologram recording material each time the irradiation position of the reproduction illumination light is changed;
A determination means for determining a predetermined characteristic portion of the reproduced image for each of the acquired irradiation positions;
Image cutting means for cutting out a predetermined characteristic portion of the reproduced image for each of the determined irradiation positions;
Image synthesizing means for synthesizing a predetermined characteristic portion of the clipped reproduction image into one reproduction image;
A hologram reproducing apparatus comprising: A hologram reproducing device that obtains a reproduced image by irradiating the hologram recording material with reproduction illumination light,
Storage means for preliminarily storing data indicating the relationship between the irradiation position of the hologram recording material of the reproduction illumination light and the predetermined characteristic portion position of the reproduction image;
Position changing means for changing the position of irradiating the hologram recording material with the reproduction illumination light while maintaining the incident angle of the reproduction illumination light at that time;
Image acquisition means for acquiring a plurality of reproduction images of the same page reproduced from the hologram recording material each time the irradiation position of the reproduction illumination light is changed;
Image cutout means for cutting out a predetermined characteristic portion of the reproduced image for each of the acquired irradiation positions based on the stored data;
Image synthesizing means for synthesizing a predetermined characteristic portion of the clipped reproduction image into one reproduction image;
A hologram reproducing apparatus comprising:   Once the determination unit determines the predetermined characteristic portion of the reproduced image for each irradiation position, the image cutout unit subsequently cuts out the predetermined characteristic portion of another reproduced image using the determination result. The hologram reproducing apparatus according to claim 1.   The determination means determines whether or not all of the acquired reproduced images are predetermined characteristic portions for each image area divided by a column of one pixel, and the image composition means is a predetermined characteristic portion. 2. The hologram reproducing apparatus according to claim 1, wherein only the determined image areas are collected to synthesize one reproduced image.   3. The hologram reproducing apparatus according to claim 1, wherein the predetermined characteristic portion of the reproduced image has a contrast ratio or diffraction efficiency of a predetermined value or more.   6. The hologram reproducing apparatus according to claim 5, wherein a threshold value is set for each image area partitioned by the reproduced image row.   7. The threshold value set for each image area partitioned by the reproduced image row is set such that the threshold value at the center portion of the page is higher than the threshold value at the edge portion of the page. The hologram reproducing apparatus as described.   8. The hologram reproducing apparatus according to claim 7, wherein a threshold value is set in accordance with a laser mode at the time of recording for each image area divided by the reproduced image row.   2. The hologram reproducing apparatus according to claim 1, wherein the determination unit determines whether or not each image region divided by a column of reproduced images has a predetermined characteristic.   10. The hologram reproducing apparatus according to claim 9, wherein the width of the image area partitioned by the reproduced image row is one pixel or more.   3. The hologram reproducing apparatus according to claim 1, wherein image data is recorded in a multiplex manner by shift multiplexing on the hologram recording material. A hologram reproducing device that obtains a reproduced image by irradiating the hologram recording material with reproduction illumination light,
Incident angle changing means for changing the angle at which the reproduction illumination light is incident on the hologram recording material;
Position changing means for changing the position of irradiating the hologram recording material with the reproduction illumination light while maintaining the incident angle of the reproduction illumination light at that time;
Image acquisition means for acquiring a reproduction image reproduced from the hologram recording material each time the irradiation position of the reproduction illumination light is changed;
A first control unit that controls the incident angle changing unit to change the incident angle of the reproduction illumination light by a predetermined angle and to acquire another image recorded in the same location of the hologram recording material by the image acquiring unit. Incident angle control means,
A plurality of images on the same page recorded at the same location of the hologram recording material are acquired by the image acquisition means by changing the irradiation position while maintaining the predetermined angle at which the reproduction illumination light is incident. Second incident angle control means for controlling the position changing means as described above,
Determination means for determining a predetermined characteristic portion of the reproduced image for each irradiation position acquired by the image acquisition means when controlled by the second incident angle control means;
Image cutting means for cutting out a predetermined characteristic portion of the reproduced image for each of the determined irradiation positions;
Image synthesizing means for synthesizing a predetermined characteristic portion of the clipped reproduction image into one reproduction image;
A hologram reproducing apparatus comprising: A determination result storing means for determining a predetermined characteristic portion of the reproduced image for each irradiation position and storing the determination result;
13. The hologram according to claim 12, wherein when the determination result is stored by the determination result storage unit, the image cutout unit cuts out a predetermined characteristic portion of another reproduced image using the determination result. Playback device. A hologram reproducing method for obtaining a reproduction image by irradiating a hologram recording material with reproduction illumination light,
Changing the position where the hologram recording material is irradiated with the reproduction illumination light; and
Each time the irradiation position of the reproduction illumination light is changed, obtaining a reproduction image reproduced from the hologram recording material;
Determining predetermined characteristic portions of each of the acquired reproduction images, and combining the predetermined characteristic portions into one reproduction image;
A hologram reproducing method comprising: A hologram reproducing method for obtaining a reproduction image by irradiating a hologram recording material with reproduction illumination light,
Storing in advance data indicating the relationship between the irradiation position of the hologram recording material of the reproduction illumination light and the predetermined characteristic portion position of the reproduction image;
Changing the position where the hologram recording material is irradiated with the reproduction illumination light; and
Each time the irradiation position of the reproduction illumination light is changed, obtaining a reproduction image reproduced from the hologram recording material;
Cutting out a predetermined characteristic portion of the reproduced image for each of the acquired irradiation positions based on the stored data;
Combining a predetermined characteristic portion of the clipped reproduction image into one reproduction image;
A hologram reproducing method comprising:

Images