Noise-compensated LCD display

• US 8,947,339 B2
• Filed: 12/21/2009
• Issued: 02/03/2015
• Est. Priority Date: 12/21/2009
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Laboratories of America Incorporated (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Feng, Xiao-fan, Daly, Scott J.
• Primary Examiner(s): Pappas, Claire X
• Assistant Examiner(s): STONE, ROBERT M
• Application Number:
  US12/655,025
• Publication Number:
  US 20110148900A1
• Time in Patent Office: 1,870 Days
• Field of Search: 345/102
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A method for displaying an input image on a display includes receiving the input image to be displayed on the display. The image is modified with a first process to determine a driving signal for a two-dimensional backlight array of independently selectable light emitting elements of the display. The first modified image is modified with a second noise reducing process to determine a driving signal for a two-dimensional liquid crystal layer defining pixels of the display. The two-dimensional backlight array has a different density of light emitting elements than the two-dimensional liquid crystal layer defining the pixels of the display.

Claims

1. A method for displaying an input image on a display comprising:

(a) receiving said input image to be displayed on said display and separating said input image into a backlight image and an LCD image, separation based at least in part on dividing said input image by said backlight image;

(b) determining a driving signal for a two-dimensional backlight array of independently selectable light emitting elements of said display by using a first process on said input image;

(c) determining a driving signal for a two-dimensional liquid crystal layer defining pixels of said display by using a second process that reduces noise present in pixel data of said input image, said second process occurring after said input image is divided by said backlight image and reducing noise based on gray-level data from said backlight array;

(d) wherein said two-dimensional backlight array has a density of light emitting elements that differs from the density of LCD elements in said two-dimensional liquid crystal layer defining said pixels of said display.

2. The method of claim 1 wherein said first process includes a non-linear filter.

3. The method of claim 1 wherein said first process sub-samples said input image.

4. The method of claim 1 wherein said first process includes a non-linear filter and sub-samples said input image.

5. The method of claim 4 further including up-sampling said input image as modified by said first process to substantially simulate the anticipated illumination from said backlight array.

6. The method of claim 5 further including the step of creating a liquid crystal layer image based upon said up-sampled input image and said input image.

7. The method of claim 6 wherein said liquid crystal layer image is filtered by said second process.

8. The method of claim 7 wherein said creating is based upon a division operation.

9. A method for displaying an input image on a display comprising:

(a) receiving said input image to be displayed on said display;

(b) using said input image to create a first signal suitable for driving a two-dimensional backlight array of independently selectable light emitting elements of said display and a second signal suitable for driving a two-dimensional liquid crystal layer defining pixels of said display, and dividing said second signal by a modified said input image;

(c) applying a noise reduction process to the divided said second signal, said noise reduction process reducing noise present in pixels of said input image.

10. The method of claim 9 wherein said first signal has been processed by a non-linear filter.

11. The method of claim 9 wherein said first signal has been processed by a sub-sampling process.

12. The method of claim 9 wherein said first signal has been processed by a non-linear filter and a sub-sampling process.

13. The method of claim 12 further including up-sampling said first signal to substantially simulate the anticipated illumination from said backlight array.

14. The method of claim 13 further including the step of creating a liquid crystal layer image based upon said up-sampled first signal and said input image.

15. The method of claim 9 wherein said separation is based upon a division operation.