Adjustment of color in displayed images based on identification of ambient light sources

• US 7,221,374 B2
• Filed: 10/21/2003
• Issued: 05/22/2007
• Est. Priority Date: 10/21/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Dixon, Brian S.
• Primary Examiner(s): LEWIS, DAVID LEE
• Application Number:
  US10/690,784
• Publication Number:
  US 20050083293A1
• Time in Patent Office: 1,309 Days
• Field of Search: 345/1.1, 345/102, 345/207, 345589- 59, 345600-602, 348/602, 348/223, 348/222.1, 348/223.1, 348/227.1, 348/366, 396/155, 395/155
• US Class Current: 345/591
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A method for adjusting color of images displayed in ambient light. A signal may be sensed from a plurality of spectral regions of an ambient light source to define a sensed signature of the ambient light source. The sensed signature may be compared to predetermined signatures of candidate light sources to identify a candidate light source that corresponds to the ambient light source. Images may be created so that the images are modified by a predefined color adjustment for the candidate light source identified.

Claims

1. A method of adjusting color of images displayed in ambient light, comprising:

sensing a signal from a plurality of spectral regions of ambient light to define a sensed signature of the ambient light;

comparing the sensed signature to predetermined signatures of light sources of different types to identify a type of light source that corresponds to the ambient light; and

projecting light to create images modified by a predefined color adjustment for the type of light source identified, the predefined color adjustment being configured to reduce a change in color rendition introduced by the type of light source identified as corresponding to the ambient light.

2. The method of claim 1, which further comprises providing a predetermined signature and a predefined color adjustment for each type of light source.

3. The method of claim 2, wherein providing a predetermined signature includes providing data relating to intensity of a type of light source in each of the spectral regions for each of the different types of light sources.

4. The method of claim 2, wherein providing a predefined color adjustment includes defining one or more lookup tables for transformation of input color values to output color values, and wherein projecting light includes modifying input values from digital image files using the one or more lookup tables of the selected color adjustment.

5. The method of claim 4, wherein defining one or more lookup tables includes defining a three-dimensional lookup table configured to transform a plurality of input color values to a single output color value.

6. The method of claim 2, wherein providing a predefined color adjustment includes defining an optical modification of one or more light components used to create the images.

7. The method of claim 6, wherein defining an optical modification includes defining a filter through which one or more of the light components will be passed during projecting light.

8. The method of claim 1, wherein sensing a signal from a plurality of spectral regions includes 1) selecting only two spectral regions that in combination produce distinguishable signatures for each of the different types of light sources, and 2) sensing an intensity from each of the only two spectral regions.

9. The method of claim 1, wherein sensing a signal for a plurality of spectral regions includes sensing the signal for each of three or more spectral regions.

10. The method of claim 1, wherein comparing includes selecting a predetermined signature that most closely corresponds to a signal sensed for each of the spectral regions.

11. The method of claim 1, wherein projecting light includes projecting light onto a refelective vertical surface.

12. The method of claim 1, wherein projecting light includes 1) selecting image representations having data corresponding to the images created by projecting light, 2) modifying the data according to the predefined color adjustment, and 3) sending the data to a light engine after modifying.

13. The method of claim 12, wherein selecting image representations includes selecting digital image files.

30. The method of claim 1, wherein comparing includes comparing the sensed signature to predetermined signatures of different types of light sources selected from the group consisting of the sun, incandescent light sources, fluorescent light sources, hybrid incandescent-fluorescent light sources, light-emitting diodes, and high-intensity discharge light sources.

14. A system for adjusting color of images displayed in ambient light, comprising:

a light engine configured to project light to create images from a set of image representations;

a light sensor for sensing a signal from each of a plurality of spectral regions of ambient light to define a sensed signature of the ambient light; and

a controller in communication with the light sensor and the light engine, the controller having access to a predetermined signature and a predefined color adjustment for each of a plurality of different types of light sources, each predefined color adjustment being configured to reduce a change in color rendition introduced by a corresponding type of light source as ambient light, the controller being configured to compare the sensed signature to the predetermined signatures to identify a type of light source that corresponds to the ambient light, the controller also being configured to select a predefined color adjustment corresponding to the type of light source identified, the controller further being configured to modify each of the images created by the light engine with the predefined color adjustment for the type of light source identified as corresponding to the ambient light.

15. The system of claim 14, wherein the light sensor includes a plurality of filters that selectively permit light from each of the spectral regions to reach the light sensor.

16. The system of claim 14, wherein the light sensor includes a plurality of sensor elements, each sensor element of the plurality being configured to sense a different one of the spectral regions.

17. The system of claim 14, wherein the controller is configured to send instructions corresponding to the image representations to the light engine, and wherein the controller is configured to apply the selected color adjustment before sending.

18. The system of claim 17, wherein the image representations include image elements each having a plurality of input color values, and wherein the selected color adjustment defines a lockup table configured to relate the plurality of input color values to a single output color value for at least a subset of the image elements.

19. The system of claim 14, wherein the controller is configured to send instructions for optical modification of light components by the light engine, the optical modification including selecting a filter through which to pass one or more of the light components.

20. A program storage device readable by a processor, tangibly embodying a program of instructions executable by the processor to perform methods steps for adjusting color of images displayed in ambient light, the method steps comprising:

providing a predetermined signature and a predefined color adjustment for each of a plurality of different types of light sources, each predefined color adustment being configured to reduce a change in color rendition introduced by a correspondinp type of light source as ambient light;

sensing a signal from a plurality of spectral regions of ambient light to define a sensed signature of the ambient light;

comparing the sensed signature to each predetermined signature to identify a type of light source that corresponds to the ambient light, thereby selecting a color adjustment based on the type of light source identified; and

projecting light to create images modified by the selected color adjustment.

21. The program storage device of claim 20, wherein providing a predetermined signature includes providing data relating to intensity of a type of light source in each of the spectral regions for each of the different types of light sources.

22. The program storage device of claim 20, wherein providing a predefined color adjustment includes defining one or more lockup tables for transformation of input color values to output color values, and wherein projecting light includes modifying input values from digital image files using the one or more lookup tables of the selected color adjustment.

23. The program storage device of claim 22, wherein defining a lockup table includes defining a three-dimensional lookup table configured to transform a plurality of input color values to a single output color value.

24. The program storage device of claim 20, wherein providing a predefined color adjustment includes defining an optical modification of one or more light components used to create the images.

25. The program storage device of claim 24, wherein defining an optical modification includes defining a filter through which one or more of the light components will be passed when projecting light.

26. The program storage device of claim 20, wherein sensing a signal from each of a plurality of spectral regions includes 1) selecting only two spectral regions that in combination produce distinguishable signatures for each of the different types of light sources, and 2) sensing an intensity from each of the only two spectral regions.

27. The program storage device of claim 20, wherein sensing a signal from a plurality of spectral regions includes sensing a signal for each of three or more spectral regions.

28. The program storage device of claim 20, wherein comparing includes selecting a predetermined signature that most closely corresponds to signals sensed from the spectral regions.

29. A system for adjusting color of images displayed in ambient light, comprising:

moans for sensing a signal from a plurality of spectral regions of ambient light to define a sensed signature of the ambient light;

means for comparing the sensed signature to predetermined signatures of different types of light sources to identify a type of light source that corresponds to the ambient light; and

projecting light to create images modified by a predefined color adjustment for the type of light source identified, the predefined color adjustment being configured to reduce a change in color rendition introduced by the type of light source identified as corresponding to the ambient light.