Hologram apparatus, positioning method for spatial light modulator and image pickup device, and hologram recording material

• US 20060039051A1
• Filed: 07/27/2005
• Published: 02/23/2006
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kihara, Nobuhiro, Baba, Shigeyuki
• Granted Patent: US 7,289,255 B2
• Time in Patent Office: Days
• US Class Current: 359/35
• CPC Class Codes: G03H 1/265 Angle multiplexing; Multichannel holograms G03H1/268 takes precedence
• CPC Class Codes: G11B 7/0065 Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
• CPC Class Codes: G11B 7/00781 Auxiliary information, e.g. index marks, address marks, pre-pits, gray codes
• CPC Class Codes: G11B 7/083 relative to record carriers storing information in the form of optical interference patterns, e.g. holograms

Abstract

The present invention provides a hologram apparatus for recording interference fringes formed from reference light and signal light optically spatially modulated by a spatial light modulator on a hologram recording material or picking up an image of reproduction signal light produced by irradiating illumination reproduction light on the hologram recording material by means of an image pickup device to obtain a reproduction image signal. The hologram apparatus includes a matching data acquisition section, an arithmetic operation section, and a positioning control section. The matching data acquisition section directly picks up an image of the signal light optically spatially modulated with a pixel matching pattern displayed on the spatial light modulator by means of the image pickup device to obtain a reproduction image signal. The arithmetic operation section performs predetermined arithmetic operation using a luminance value of the reproduction image signal. The positioning control section moves a relative position between the image pickup device and the spatial light modulator in response to a result of the arithmetic operation of the arithmetic operation section.

Claims

1. A hologram apparatus for recording interference fringes formed from reference light and signal light optically spatially modulated by a spatial light modulator on a hologram recording material or picking up an image of reproduction signal light produced by irradiating illumination reproduction light on the hologram recording material by means of an image pickup device to obtain a reproduction image signal, comprising:

a matching data acquisition section for directly picking up an image of the signal light optically spatially modulated with a pixel matching pattern displayed on said spatial light modulator by means of said image pickup device to obtain a reproduction image signal;

an arithmetic operation section for performing predetermined arithmetic operation using a luminance value of the reproduction image signal; and

a positioning control section for moving a relative position between said image pickup device and said spatial light modulator in response to a result of the arithmetic operation of said arithmetic operation section.

2. The hologram apparatus according to claim 1, wherein said positioning control section moves said image pickup device with respect to said spatial light modulator or moves said spatial light modulator with respect to said image pickup device in response to the result of the arithmetic operation of said arithmetic operation section.

3. The hologram apparatus according to claim 1, wherein said image pickup device has a resolution higher than that of said spatial light modulator, and said matching data acquisition section oversamples the signal light optically spatially modulated with the pixel matching pattern.

4. The hologram apparatus according to claim 3, wherein the resolution of said image pickup device is equal to or higher than twice that of said spatial light modulator.

5. The hologram apparatus according to claim 1, wherein said arithmetic operation section calculates a square sum of differences between luminance values of a plurality of successive pixels of said image pickup device and then calculates a sum total of such square sums or calculates a sum total of differences between luminance values of a plurality of successive pixels.

6. The hologram apparatus according to claim 5, wherein said arithmetic operation section calculates the sum total of the square sums and determines the calculated sum total as an evaluation function or calculates the sum total of the differences and determines the calculated sum total as an evaluation function, takes a plurality of line profiles from the reproduction image signal, integrates the profiles, and calculates an evaluation value based on the evaluation function from the integrated profile.

7. The hologram apparatus according to claim 1, wherein said positioning control section moves the mechanical position of said image pickup device to position said image pickup device so that the result of the arithmetic operation of said arithmetic operation section has a maximum value.

8. The hologram apparatus according to claim 1, wherein the pixel matching pattern is formed from an alternate pattern and is displayed in a scattered manner at a plurality of places on a display screen of said spatial light modulator.

9. The hologram apparatus according to claim 1, wherein the pixel matching pattern is formed from an elongated alternate pattern of two values disposed between each adjacent ones of positioning marks disposed at four corners of a display screen of said spatial light modulator.

10. A hologram apparatus for picking up an image of reproduction signal light reproduced by irradiating illumination reproduction light on a hologram recording material by means of an image pickup device to obtain a reproduction image signal, comprising:

a matching data acquisition section for picking up an image of reproduction signal light obtained by reproduction of a pixel matching pattern recorded in advance in the hologram recording material by means of said image pickup device to obtain a reproduction image signal;

an arithmetic operation section for performing predetermined arithmetic operation using a luminance value of the reproduction image signal; and

a positioning control section for moving a relative position between said image pickup device and said spatial light modulator in response to a result of the arithmetic operation of said arithmetic operation section.

11. The hologram apparatus according to claim 10, wherein said positioning control section moves said image pickup device with respect to said spatial light modulator or moves said spatial light modulator with respect to said image pickup device in response to the result of the arithmetic operation of said arithmetic operation section.

12. The hologram apparatus according to claim 10, wherein said image pickup device has a resolution higher than that of said spatial light modulator, and said matching data acquisition section oversamples the signal light optically spatially modulated with the pixel matching pattern.

13. The hologram apparatus according to claim 12, wherein the resolution of said image pickup device is equal to or higher than twice that of said spatial light modulator.

14. The hologram apparatus according to claim 10, wherein said arithmetic operation section calculates a square sum of differences between luminance values of a plurality of successive pixels of said image pickup device and then calculates a sum total of such square sums or calculates a sum total of differences between luminance values of a plurality of successive pixels.

15. The hologram apparatus according to claim 14, wherein said arithmetic operation section calculates the sum total of the square sums and determines the calculated sum total as an evaluation function or calculates the sum total of the differences and determines the calculated sum total as an evaluation function, takes a plurality of line profiles from the reproduction image signal, integrates the profiles, and calculates an evaluation value based on the evaluation function from the integrated profile.

16. The hologram apparatus according to claim 10, wherein said positioning control section moves the mechanical position of said image pickup device to position said image pickup device so that the result of the arithmetic operation of said arithmetic operation section has a maximum value.

17. The hologram apparatus according to claim 10, wherein the pixel matching pattern is formed from an alternate pattern and is displayed in a scattered manner at a plurality of places on a display screen of said spatial light modulator.

18. The hologram apparatus according to claim 10, wherein the pixel matching pattern is formed from an elongated alternate pattern of two values disposed between each adjacent ones of positioning marks disposed at four corners of a display screen of said spatial light modulator.

19. A positioning method for a spatial light modulator and an image pickup device in a hologram apparatus which records interference fringes formed from reference light and signal light optically spatially modulated by said spatial light modulator or picks up an image of reproduction signal light produced by irradiating illumination reproduction light on the hologram recording material by means of said image pickup device to obtain a reproduction image signal, comprising the steps of:

displaying a pixel matching pattern on said spatial light modulator;

directly picking up an image of the signal light optically spatially modulated with the pixel matching pattern displayed on said spatial light modulator by means of said image pickup device to obtain a reproduction image signal;

performing predetermined arithmetic operation using a luminance value of the reproduction image signal; and

moving a relative position between said image pickup device and said spatial light modulator in response to a result of the arithmetic operation.

20. A positioning method for a spatial light modulator and an image pickup device in a hologram apparatus which picks up an image of reproduction signal light reproduced by irradiating illumination reproduction light on a hologram recording material by means of an image pickup device to obtain a reproduction image signal, comprising the steps of:

reproducing a pixel matching pattern recorded in advance in the hologram recording material to obtain reproduction signal light;

picking up an image of the reproduction signal light by means of the image pickup device to obtain a reproduction image signal;

performing predetermined arithmetic operation using a luminance value of the reproduction image signal; and

moving a relative position between said image pickup device and said spatial light modulator in response to a result of the arithmetic operation.

21. A hologram recording material for recording interference fringes formed from reference light and signal light optically spatially modulated by a spatial light modulator, said hologram recording material having recorded therein a pattern for correction of positional displacement on the pixel level between an image pickup device for picking up a reproduction image when recorded data of said hologram recording material are reproduced and said spatial light modulator.