Technique that preserves specular highlights

• US 20060103621A1
• Filed: 09/22/2005
• Published: 05/18/2006
• Est. Priority Date: 11/16/2004
• 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
• Granted Patent: US 7,525,528 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements and a light valve. A image signal is received and a first light emitting element is illuminated based upon a substantial maximum of a non-uniform image signal in a first region. A second light emitting element is illuminated based upon a substantial maximum of a non-uniform image signal in a second region including, where the first and second light emitting elements are simultaneously illuminated.

Claims

1. A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements and a light valve comprising:

(a) receiving an image signal;

(b) illuminating a first light emitting element based upon a substantial maximum of a non-uniform said image signal in a first region including said first light emitting element;

(c) illuminating a second light emitting element based upon a substantial maximum of a non-uniform said image signal in a second region including said second light emitting element;

(d) wherein said first and second light emitting elements are simultaneously illuminated.

2. The method of claim 1 wherein said illumination of said light emitting element is based upon said image signal.

3. The method of claim 1 wherein said light emitting element is located in a spatial region behind said light valve.

4. The method of claim 1 wherein the light provided by said display in said first region is based upon the transmittance of said light valve in said first region and the luminance of said first light emitting element in said first region.

5. The method of claim 1 wherein said light valve in said first region is operated at a range between 0.25 and 0.75 of its dynamic range.

6. The method of claim 5 wherein said light valve in said first region is operated at a range between 0.4 and 0.6 of its dynamic range.

7. The method of claim 1 wherein said image signal is re-sampled to a lower resolution before determining said substantial maximum for said first region.

8. The method of claim 7 wherein said image signal is re-sampled in a plurality of overlapping regions.

9. The method of claim 1 wherein said substantial maximum is characterized by is an image signal that has a substantially uniform distribution of intensity values across the image where the variability in the luminance has one standard deviation and said substantial maximum is selected as being within 0.5 standard deviation.

10. A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements and a light valve comprising:

(a) receiving an image signal;

(b) low pass filtering and re-sampling said image signal;

(c) defining a substantial maximum of a re-sampled said image signal;

(d) selectively selecting one of said re-sampled signal and said substantial maximum signal;

(e) providing a signal based upon said selected signal to one of said light emitting elements.

11. The method of claim 10 wherein steps (a) though (e) are performed for another said light emitting elements.

12. The method of claim 11 wherein said signal for said one of said light emitting elements and said signal for another said light emitting elements are modified based upon crosstalk.

13. A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements and a light valve comprising:

(a) receiving an image signal;

(b) providing light from said display in a first region of said display based upon light from a first light emitting element in said first region together with the transmittance of said light valve in said first region;

(c) providing light from said display in a second region of said display based upon light from a second light emitting element in said second region together with the transmittance of said light valve in said second region;

(d) wherein said image signal in said first region provides a signal to said first light emitting element and said light valve in such a manner that a maximum image signal is displayed at an illumination greater than the illumination of a next smaller image signal than said maximum image signal and wherein said light valve has the same value for said maximum image signal and said next smaller value;

(e) wherein said image signal in said second region provides a signal to said second light emitting element and said light valve in such a manner that a maximum image signal is displayed at an illumination greater than the illumination of a next smaller image signal than said maximum image signal and wherein said light valve has the same value for said maximum image signal and said next smaller value;

(f) wherein light is simultaneously provided from said first region and said second region.

14. The method of claim 13 wherein said illumination of said light emitting element is based upon said image signal.

15. The method of claim 13 wherein said light emitting element is located in a spatial region behind said light valve.

16. The method of claim 13 wherein said image signal is re-sampled in a plurality of overlapping regions.

17. A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements and a light valve comprising:

(a) receiving an image signal;

(b) filtering different regions of said image signal in such a manner that regions with low specular highlights are filtered in a first manner and regions with high specular highlights are filtered in a second manner;

(c) providing said filtered image data to said plurality of light emitting elements.

18. A method for displaying an image on a liquid crystal display that includes a plurality of light emitting elements arranged as an array and a light valve comprising:

(a) receiving an image signal including an indication of red, green, and blue for a pixel;

(b) illuminating a first light emitting element, wherein said first light emitting element is a light emitting diode, based upon a luminance determination from said indication where said blue comprises at least 15% of the total of said luminance.