METHODS AND SYSTEMS FOR ADJUSTING COLOR GAMUT IN RESPONSE TO AMBIENT CONDITIONS

• US 20140063039A1
• Filed: 08/30/2012
• Published: 03/06/2014
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Drzaic, Paul Stephen
• Granted Patent: US 9,019,253 B2
• Time in Patent Office: Days
• US Class Current: 345/589
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

Systems and methods for adjusting a color space of a display. In one embodiment, the method for adjusting the color space of the display may include receiving image data to be rendered on the display and receiving an indication of an amount of ambient light impinging on the display. The method may then include rendering the image data in a first color space when the amount of ambient light is less than a threshold. Alternatively, the method may include rendering the image data in an expanded color space when the amount of ambient light is not less than the threshold. As such, the expanded color space may compensate for one or more color shifts in the image data caused by the ambient light.

Claims

1. A method, comprising:

receiving image data to be rendered on the display;

receiving an indication of an amount of ambient light impinging on the display;

rendering the image data in a first color space when the amount of ambient light is less than a threshold; and

rendering the image data in an expanded color space when the amount of ambient light is not less than the threshold, wherein rendering the image data in the expanded color space is configured to compensate for one or more color shifts in the image data caused by the ambient light.

2. The method of claim 1, wherein rendering the image data in the expanded color space comprises rendering the image data in an Adobe®

RGB color space.

3. The method of claim 1, wherein rendering the image data in the expanded color space comprises:

determining a magnitude in which to expand the first color space based at least in part on the amount of ambient light; and

expanding the first color space based at least in part on the magnitude.

4. The method of claim 3, wherein the magnitude in which to expand the first color space is linearly proportional to a difference between the amount of ambient light and the threshold.

5. The method of claim 1, wherein rendering the image data in the expanded color space comprises rendering one or more colors in the image data at their respective maximum or substantially maximum saturation levels.

6. The method of claim 1, comprising increasing a gamma response of the display based at least in part on the amount of ambient light and the color shifts in the image data.

7. The method of claim 6, wherein increasing the gamma response of the display comprises increasing a luminance difference between one or more lower gray levels in the display and one or more higher gray levels in the display.

8. The method of claim 1, comprising adjusting a gamma curve of the display based at least in part on the amount of ambient light and the color shifts in the image data.

9. The method of claim 1, wherein rendering the image data in the expanded color space comprises:

receiving color data that corresponds to one or more pixels in the image data;

determining reflected color data based at least in part on the display and the amount of ambient light, wherein the reflected color data represents the indication of the amount of the ambient light;

determining the color shifts in the image data due at least in part to the reflected color data, wherein each color shift corresponds to a respective shift in color in each respective pixel due to the reflected color data;

determining one or more color compensation factors for the color shifts based at least in part on the color shifts; and

applying the color compensation factors to the pixels.

10. A system comprising:

a processor configured to generate image data;

a display configured to depict the image data;

an ambient light sensor configured to detect an amount of ambient light impinging on the display; and

a controller configured to adjust a color space of the image data by;

receiving color data that corresponds to the image data;

determining reflected color data based at least in part on the display and an amount of ambient light impinging on the display;

determining one or more color shifts in the image data due at least in part to the reflected color data;

determining one or more color compensation factors for the color shifts based at least in part on the color shifts; and

applying the color compensation factors to the image data.

11. The system of claim 10, wherein the color data comprises Yxy variables for each pixel in the image data.

12. The system of claim 10, wherein the controller is further configured to receive one or more ambient light measurements from the ambient light sensor, wherein the ambient light measurements correspond to the amount of ambient light

13. The system of claim 10, wherein the reflected color data is based at least in part on a portion of the ambient light that reflects off a front surface of the display, one or more interfaces within the display, one or more metallic or conducting layers in the display, or any combination thereof.

14. The system of claim 10, wherein the controller is configured to determine the reflected color data by:

determining a type of ambient light impinging on the display based at least in part on the amount of ambient light; and

setting the reflected color data to have D65 white point x,y values when the type of ambient light corresponds outdoor ambient light.

15. The system of claim 10, wherein the color compensation factors are configured to:

increase a luminance of the display by an amount substantially equal to an amount of luminance in the reflected color data; and

shift one or more color coordinates of the image data in one or more opposite directions with respect to the color shifts.

16. The system of claim 10, wherein the display is a liquid crystal display or an organic light emitting diode (OLED) display.

17. An electronic device, comprising:

a display configured to display one or more images;

a controller configured to adjust a color gamut of the display by;

receiving image data to be rendered on the display;

receiving an ambient light measurement that indicates an amount of ambient light impinging on the display;

rendering the image data in a first color space when the ambient light measurement is less than a threshold; and

rendering the image data in an expanded color space when the amount of ambient light is not less than the threshold.

18. The electronic device of claim 17, wherein the image data rendered in the expanded color space are configured to compensate for a white color component added to the image data by the ambient light.

19. The electronic device of claim 17, wherein the controller is configured to render the image data in the expanded color space by increasing the color saturation levels of each color in the image data.

20. An organic light emitting diode (OLED) display device, comprising:

a controller configured to adjust a color space of the OLED display device based at least in part on an amount of light impinging on the OLED display device by;

receiving Yxy variables for each pixel in image data configured to be depicted on the OLED display device;

determining reflected Yxy variables for each pixel in the image data based at least in part on the amount of light impinging on the OLED display device;

determining a shift in the Yxy variables for each pixel due to the respective reflected Yxy variables for each pixel;

determining Yxy compensation variables for each pixel based at least in part on the shift in the Yxy variables for each pixel due to the respective reflected Yxy variables for each pixel; and

applying the Yxy compensation variables to each pixel.

21. The OLED display device of claim 20, wherein the shift in the Yxy variables for each pixel is determined according to:

22. The OLED display device of claim 21, wherein the Yxy compensation variables are determined according to: