LCD image compensation for LED backlighting

• US 8,564,528 B1
• Filed: 05/18/2011
• Issued: 10/22/2013
• Est. Priority Date: 05/18/2011
• Status: Active Grant

• Current Assignee: Pixelworks Incorporated
• Original Assignee: Pixelworks Incorporated
• Inventors: Chen, Tao, Woodall, Neil D., Zhang, Bob, Zhou, James
• Primary Examiner(s): HALEY, JOSEPH R
• Application Number:
  US13/110,745
• Time in Patent Office: 888 Days
• Field of Search: None
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A method, includes receiving original image data having a first resolution, dividing the original image data into zones based upon a second resolution, wherein the second resolution corresponds to a resolution of backlight elements, determining a backlight value for each zone, and adjusting the original image data in each block to compensate for the backlight value for each zone to produce compensated image data, wherein adjusting the original image data comprises using the backlight value and an original image data value as indexes into at least one look-up table to acquire compensated image data. An apparatus has a source of original image data, a display panel of individual elements, a backlight of individual lighting elements, at least one look-up table having compensated image data, and a processor to determine a backlight value for each individual lighting element, and adjust the original image data to compensate for the backlight value and produce compensated image data by using the backlight value and an original image data value as indexes into the look-up table.

Claims

1. A method, comprising:

receiving original image data having a first resolution;

dividing the original image data into zones based upon a second resolution, wherein the second resolution corresponds to a resolution of backlight elements;

determining a backlight value for each zone and a backlight image value; and

adjusting the original image data in each block to compensate for the backlight value for each zone to produce compensated image data, wherein adjusting the original image data comprises using the backlight image value and an original image data value as indexes into a two-dimensional look-up table to acquire a compensated image data.

2. The method of claim 1, wherein receiving image data having a first resolution comprises receiving image data for a liquid-crystal device display.

3. The method of claim 1, wherein determining the backlight value for each zone comprises setting the backlight value to a maximum image data value for the zone.

4. The method of claim 1, wherein determining the backlight value for each zone comprises setting the backlight value to an average image data value for the zone.

5. The method of claim 1, wherein determining the backlight value for each zone comprises blending of an average image data value and a maximum image data value for the zone.

6. The method of claim 5, wherein blending the average image data value and the maximum image data value comprises providing a weight factor based upon a histogram of the zone.

7. An apparatus, comprising:

a source of original image data;

a display panel of individual elements;

a backlight of individual lighting elements;

a two-dimensional look-up table having compensated image data;

a processor to;

determine a backlight image value for each individual element; and

adjust the original image data to compensate for the backlight value and produce compensated image data by using the backlight image value and an original image data value as indexes into the two-dimensional look-up table.

8. The apparatus of claim 7, wherein the processor comprises a video processor.

9. The apparatus of claim 7, wherein the processor comprises a post-processor.

10. The apparatus of claim 9, wherein the display panel comprises a liquid crystal device panel.

11. The apparatus of claim 7, wherein the processor is further to multiply the weight by the initial compensated image data value to determine produce the compensated image data.

12. A method, comprising:

receiving original image data having a first resolution;

dividing the original image data into zones based upon a second resolution, wherein the second resolution corresponds to a resolution of backlight elements;

determining a backlight image value for each zone and a backlight image value; and

adjusting the original image data in each block to compensate for the backlight value for each zone to produce compensated image data, wherein adjusting the original image data comprises;

using the backlight image value to access a first one-dimensional look-up table to acquire a weight;

using the original image data value to access a second one-dimensional look-up table to acquire an initial compensated image data value; and

multiplying the weight by the initial compensated image data value to produce a compensated image data value.

13. An apparatus, comprising:

a source of original image data;

a display panel of individual elements;

a backlight of individual lighting elements;

two one-dimensional look-up tables having compensated image data;

a processor to;

determine a backlight image value for each individual element; and

adjust the original image data to compensate for the backlight value and produce compensated image data by using the backlight value as an index into a first of the two look-up tables to acquire a weight and the original image data value as an index into a second of the two look-up tables to acquire an initial compensated image data value.