Light source response compensation for light projection system using a graphics processing unit

Patent metadata

Field	Value
Publication number	US-10469813-B2
Application number	US-201816032634-A
Country	US
Kind code	B2
Filing date	Jul 11, 2018
Priority date	Dec 21, 2017
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A light projection system includes a light module emitting a light beam and a movable mirror reflecting the light beam toward a surface. A graphics processing unit processes video data to compensate for a response of the light module. The response is an optical power of the light beam produced by the light module for a given forward current through the light module. A light source driver controls the light module as a function of the processed video data. Colors of the images from the video data produced on the surface by the light beam would otherwise not look as they are intended to look due to changing of the response of the light module, but the processing of the video data alters the video data such that the colors of the images from the video data produced on the surface look as they are intended to look.

First claim

The invention claimed is:

1. A light projection system, comprising:
a light module configured to emit a light beam;
a movable mirror apparatus configured to reflect the light beam toward a surface;
a graphics processing unit (GPU) configured to:
receive video data;
estimate positions of the light beam on the surface to reproduce images encoded within the video data;
generate pixel color values of the video data as a function of the estimated positions of the light beam on the surface; and
process the pixel color values of the video data to compensate for a response of the light module so that a response of the light module is linear, the response of the light module being an optical power of the light beam produced by the light module for a given forward current through the light module;

a light source driver configured to control the light module as a function of the processed video data; and
wherein colors of the images produced on the surface by the light beam would otherwise not look as they are intended to look due to changing of the response of the light module, but the processing of the pixel color values serves to alter the pixel color values such that the colors of the images produced on the surface do look as they are intended to look.

2. The light projection system of claim 1 , wherein the response of the light module would otherwise be non-linear but the processing of the pixel color values of the video data compensates the video data such that the light source driver controls the light module so that the response is linear.

3. The light projection system of claim 1 , wherein the GPU is further configured to store uncompensated pixel color values as correlated to compensated pixel color values in a lookup table; and
wherein the GPU is further configured to compensate the pixel color values using the lookup table by replacing the pixel color values with corresponding ones of the compensated pixel color values from the lookup table so that when the light source driver controls the light module as a function of the processed video data, the light source driver controls the light module so that the response is linear.

4. The light projection system of claim 3 , wherein the GPU processes the pixel color values of the video data by performing a lookup of compensated pixel color values in the lookup table based upon the pixel color values.

5. The light projection system of claim 1 , wherein the GPU is configured to estimate the response of the light module, and to process the pixel color values of the video data based thereupon.

6. The light projection system of claim 1 , wherein the optical power of the light beam produced by the light module for a given forward current through the light module changes as a function of temperature; and wherein the processing of the pixel color values of the video data compensates the video data for that change of the optical power of the light beam produced by the light module for the given forward current through the light module.

7. A light projection system, comprising:
a light module configured to emit a light beam;
a movable mirror apparatus configured to reflect the light beam toward a surface;
a graphics processing unit (GPU) configured to:
receive video data;
estimate positions of the light beam on the surface to reproduce images encoded within the video data;
generate pixel color values of the video data as a function of the estimated positions of the light beam on the surface; and
process the pixel color values of the video data based upon a response of the light module so that a response of the light module is linear, the response of the light module being an optical power of the light beam produced by the light module, the optical power being a function of a color intended to be produced by the light beam;

a light source driver configured to control the light module as a function of the processed video data; and
wherein the processing of the video data serves to alter the pixel color values such that colors produced by the light beam for a given optical power match pixel colors specified by the video data prior to the processing of the pixel color values.

8. The light projection system of claim 7 , wherein the response of the light module would otherwise be non-linear but the processing of the pixel color values of the video data compensates the video data such that the light source driver controls the light module so that the response is linear.

9. The light projection system of claim 7 , wherein the GPU is further configured to store uncompensated pixel color values as correlated to compensated pixel color values in a lookup table; and
wherein the GPU is further configured to compensate the pixel color values using the lookup table so that when the light source driver controls the light module as a function of the processed video data, the light source driver controls the light module so that the response is linear.

10. The light projection system of claim 9 , wherein the GPU, during subsequent operation, processes the pixel color values of the video data by performing a lookup of compensated pixel color values in the lookup table based upon the pixel color values.

11. The light projection system of claim 7 , wherein the optical power of the light beam produced by the light module for a given forward current through the light module changes as a function of temperature; and wherein the processing of the pixel color values of the video data compensates the video data for that change of the optical power of the light beam produced by the light module for a given forward current through the light module.

12. A light projection system, comprising:
a light module configured to emit a light beam;
a movable mirror apparatus configured to reflect the light beam toward a surface;
an input coupled to receive video data;
a light source driver configured to control the light module as a function of the video data; and
a graphics processing unit (GPU) configured to:
receive the video data;
estimate positions of the light beam on the surface to reproduce images encoded within the video data;
generate pixel color values of the video data as a function of the estimated positions of the light beam on the surface; and
process the pixel color values to compensate for an operating temperature of the light module so that colors in an image produced by the light beam on the surface appear as intended regardless of the operating temperature of the light module and sending the processed video data to the light source driver.

13. A method, comprising:
receiving video data from a video source;
estimating a position of a light beam projected by a scanning light projector onto a surface to thereby reproduce an image encoded within the video data;
generate pixel color values for the video data, as a function of the estimated position of the light beam on the surface; and
compensating the pixel color values so that a response of a light module generating the light beam is linear, the response of the light module being an optical power of the light beam produced by the light module for a given forward current through the light module.

14. The method of claim 13 , wherein the pixel color values are compensated by performing a lookup of compensated pixel color values in a lookup table and replacing the pixel color values with corresponding ones of the compensated pixel color values from the lookup table.

15. A light projection system comprising:
a light module configured to emit a light beam;
a movable mirror apparatus configured to reflect the light be

Assignees

• St Microelectronics Srl
• St Microelectronics Ltd

Inventors

• Ratti Massimo
• Petrushevsky Naomi
• Yaser Eli
• Nachimias Yotam

Classifications

• G02B27/017

  Head mounted · CPC title

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B26/0858

  the reflecting means being moved or deformed by piezoelectric means · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• H04N9/3135

  Driving therefor · CPC title