STEREOSCOPIC IMAGE INTENSITY BALANCING IN LIGHT PROJECTOR

• US 20100328429A1
• Filed: 06/25/2009
• Published: 12/30/2010
• Est. Priority Date: 06/25/2009
• Status: Active Grant

• Current Assignee: IMAX Corporation
• Original Assignee: Eastman Kodak Company
• Inventors: Corey, Richard P., Silverstein, Barry D.
• Granted Patent: US 8,237,777 B2
• Time in Patent Office: Days
• US Class Current: 348/46
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/327 Calibration thereof
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/346 using prisms or semi-transparent mirrors
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388

Abstract

In a light projection system, potentially hierarchical levels of light intensity control ensure proper laser-light output intensity, color channel intensity, white point, left/right image intensity balancing, or combinations thereof The light projection system can include a light intensity sensor in an image path, in a light-source subsystem light-dump path, in a light-modulation subsystem light-dump path, in a position to measure light leaked from optical components, or combinations thereof.

Claims

1. A stereoscopic light projection system comprising:

a stereoscopic image forming subsystem configured at least to output stereoscopic light comprising left-eye and right-eye light beams; and

a light-intensity-correction subsystem configured at least to (a) determine a difference in light intensity between the left-eye and right-eye light beams and (b) control the stereoscopic image forming subsystem to change an intensity of the left-eye light beam or right eye light beam if an absolute value of the determined difference in light intensity exceeds a threshold amount.

2. The system of claim 1, wherein the light-intensity-correction subsystem comprises a light-intensity sensor in a path of the left-eye light beam and the right-eye light beam.

3. The system of claim 2, wherein the stereoscopic image forming subsystem comprises:

a light source subsystem configured at least to alternately generate the left-eye and right-eye light beams of the stereoscopic light, wherein when the left-eye light beam or the right-eye light beam is being generated for the stereoscopic light, the other of the left-eye or right-eye light beams is transmitted along a light dump path to a beam dump associated with the light source subsystem, and

a light modulation subsystem configured at least to generate stereoscopic images from the stereoscopic light in a manner consistent with image data,

wherein the light-intensity sensor is in the light dump path.

4. The system of claim 2, wherein the sensor is on a shutter in a closed position that prevents further projection of the left-eye light beam and the right-eye light beam.

5. The system of claim 1, further comprising:

a projection subsystem configured at least to project a stereoscopic image,

wherein the stereoscopic image forming subsystem comprises;

a coherent light source subsystem configured at least to emit coherent light; and

a light modulation subsystem configured at least to interact with the coherent light in a manner consistent with image data,

wherein the light modulation subsystem causes the left-eye and right-eye light beams each to follow either a light dump path or an image path in a manner consistent with the image data, and

wherein the light dump path does not lead to the projection subsystem and the image path does lead to the projection subsystem.

6. The system of claim 5, wherein both the left-eye and right-eye light beams share a light dump path, and wherein the light-intensity-correction subsystem includes a light-intensity sensor in the shared light dump path.

7. The system of claim 1, wherein the stereoscopic image forming subsystem is configured at least to output stereoscopic light of multiple color channels, and wherein the left-eye and right-eye light beams are stereoscopic light of a single color channel of the multiple color channels.

8. The system of claim 7, wherein each of the multiple color channels has its own associated left-eye and right-eye light beams, and wherein the light-intensity-correction subsystem is configured at least to (a) determine a difference in light intensity between the left-eye and right-eye light beams for each of the multiple color channels and (b) control the stereoscopic image forming subsystem to change an intensity of the left-eye light beam or right eye light beam of a color channel if an absolute value of the determined difference in light intensity for that color channel exceeds a threshold amount.

9. The system of claim 8, wherein the light-intensity-correction subsystem comprises a white point control subsystem configured at least to (a) determine a white point of the multiple color channels, and (b) control the stereoscopic image forming subsystem to change an intensity of one or more of the color channels if an absolute value of the determined white point deviates from a predetermined white point by a threshold amount.

10. The system of claim 1, wherein the left-eye and right-eye light beams have polarization or spectral differences.

11. A method for correcting light intensity generated by an image forming system, the method comprising:

generating, from the image forming system, stereoscopic light comprising left-eye and right-eye light beams;

determining a difference in light intensity between the left-eye and right-eye light beams; and

changing an intensity of the left-eye light beam or the right-eye light beam if an absolute value of the determined difference in light intensity exceeds a threshold amount.

12. The method of claim 11,

wherein the stereoscopic light is generated by alternately generating the left-eye and right-eye light beams with a light source subsystem, the light source subsystem included within the image forming,

wherein when the left-eye light beam or the right-eye light beam is being generated for the stereoscopic light, the other of the left-eye or right-eye light beams is transmitted along a light dump path to a beam dump associated with the light source subsystem,

wherein the method further comprises generating stereoscopic images from the stereoscopic light with a light modulation subsystem in a manner consistent with image data, and

wherein the difference in light intensity between the left-eye and right-eye light beams is determined based at least upon information received from a light-intensity sensor in the light dump path.

13. The method of claim 11, further comprising:

generating stereoscopic images from the stereoscopic light with a light modulation subsystem in a manner consistent with image data;

projecting the stereoscopic images with a projection subsystem,

wherein the light modulation subsystem causes the left-eye and right-eye light beams each to follow either a light dump path or an image path in a manner consistent with the image data,

wherein the light dump path does not lead to the projection subsystem and the image path does lead to the projection subsystem, and

wherein the difference in light intensity between the left-eye and right-eye light beams is determined based at least upon information received from a light-intensity sensor in the light dump path.

14. The method of claim 11, wherein the determining and changing occurs during or contemporaneously with completion of construction of the image forming system.

15. The method of claim 11, wherein the determining and changing occurs during or contemporaneously with a startup procedure initiated by a powering-on or rebooting of the image forming system.

16. The method of claim 11, wherein the determining and changing occurs just prior to projecting a video with the image forming system.

17. The method of claim 11, wherein the image forming system comprises a plurality of light source subsystems each configured at least to generate a single color channel of multiple different color channels of light capable of being generated by the image forming system, wherein the left-eye and right-eye light beams are stereoscopic light of a single color channel of the multiple color channels, and wherein the determining occurs when only one of the plurality of light source subsystems are generating light.

18. The method of claim 17, wherein the determining occurs at least by a light-intensity sensor on a shutter, and wherein the method further comprises closing the shutter into a closed position that prevents further projection of the left-eye light beam and the right-eye light beam, the closing occurring prior to the determining.

19. The method of claim 18,

wherein the determining determines a difference in light intensity between the left-eye and right-eye light beams at least by taking light-intensity measurements from the left-eye light beam and the right-eye light beam during blanking periods between generation of the left-eye and right-eye light beams.

20. The method of claim 11, wherein the image forming system comprises a plurality of light source subsystems each configured at least to generate a single color channel of multiple different color channels of light generated by the image forming system, wherein the left-eye and right-eye light beams are stereoscopic light of a single color channel of the multiple color channels, and wherein the method further comprises:

determining a white point of the multiple color channels, and

controlling the image forming system to change an intensity of one or more of the color channels if an absolute value of the determined white point deviates from a predetermined white point by a threshold amount.