High dynamic range images from low dynamic range images

• US 20060104533A1
• 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: Daly, Scott J., Meylan, Laurence
• Granted Patent: US 8,050,512 B2
• Time in Patent Office: Days
• US Class Current: 382/254
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping

Abstract

A method for displaying an image includes receiving an image having a first luminance dynamic range and modifying the image to a second luminance dynamic range free from being based upon other images, where the second dynamic range is greater than the first dynamic range. The modified image is displayed on a display.

Claims

1. A method for displaying an image comprising:

(a) receiving an image having a first luminance dynamic range;

(b) modifying said image to a second luminance dynamic range free from being based upon other images, wherein said second dynamic range is greater than said first dynamic range; and

(c) displaying said modified image a display.

2. The method of claim 1 wherein said first dynamic range is less than 3 log units.

3. The method of claim 2 wherein said second dynamic range is greater than 4 log units.

4. The method of claim 1 wherein said second dynamic range is at least 1 log unit greater than said first dynamic range.

5. The method of claim 1 wherein said second dynamic range is at least 2 log units greater than said first dynamic range.

6. The method of claim 1 wherein said receiving, modifying, and displaying is all performed by said display.

7. The method of claim 1 wherein said receiving, modifying, and displaying is all performed within said display.

8. A display having a light valve comprising:

(a) receiving an image signal having a first luminance dynamic range and first digital code value dynamic range;

(b) modifying said image signal to a second luminance dynamic range in a non-linear manner and a second digital code value dynamic range, where said second luminance dynamic range is greater than said first luminance dynamic range and said second digital code value is greater than said first digital code value dynamic range;

(c) display said modified image signal on said display.

9. The display of claim 8 wherein said second luminance dynamic range is at least 2 log units greater than said first luminance dynamic range.

10. The display of claim 8 wherein said modifying is free from being based upon other images.

11. The display of claim 8 wherein said modifying is a spatial process.

12. The display of claim 8 wherein said modifying is based upon said image signal.

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

(a) receiving an image having at least one of;

(i) a first dynamic range;

(ii) a first black point;

(iii) a first white point;

(b) modifying said image to a respective at least one of;

(i) a second dynamic range;

(ii) a second black point;

(iii) a second white point;

(c) wherein said second dynamic range is greater than said first dynamic range, said second black point is different than said first black point, and said second white point is different than said first white point;

(d) wherein two different images are received, each of which has a different at least one of said first dynamic range, said first black point, and said first white point, that are said modified to the same respective said second dynamic range, said second black point, and said second white point;

(e) displaying said modified image on said display.

14. The method of claim 13 wherein said at least one of includes said first dynamic range, wherein said second dynamic range free from being based upon other images.

15. The method of claim 13 wherein said at least one of includes said first black point.

16. The method of claim 13 wherein said at least one of includes said first white point.

17. The method of claim 13 wherein said at least one of includes said first dynamic range, wherein said second dynamic range is a second luminance dynamic range, said second luminance dynamic range is greater than said first dynamic range.

18. A method for displaying an image comprising:

(a) receiving an image having a first dynamic range;

(b) modifying said image to a second dynamic range, wherein said second dynamic range is greater than said first dynamic range, wherein the lower range of said first dynamic range is mapped to the lower range of said second dynamic range with a first function, wherein the higher dynamic range of said first dynamic range is mapped to the higher range of said second dynamic range with a second function, wherein said first function has a denser mapping than said second function;

(c) displaying said modified image a display.

19. The method of claim 18 wherein a point between said first function and said second function is generally coincident with the diffuse region maximum value.

20. A method for modifying an image to be displayed on a display comprising:

(a) receiving an image;

(b) determining a substantially specular maximum of said image;

(c) determining a substantially diffuse maximum of said image;

(d) determining a mapping function based upon said substantial specular maximum and said substantial diffuse maximum;

(e) modifying said image based upon said mapping function to provide a modified image with an increased dynamic range;

(f) displaying said modified image on said display.

21. The method of claim 20 wherein said substantially diffuse maximum is determined based upon a low pass filtering operation.

22. The method of claim 20 wherein said substantaially specular maximum of said image is based upon a maximum operation.

23. The method of claim 20 wherein said mapping function includes at least two functions, a first function used below said substantially diffuse maximum and a second function used above said substantially diffuse maximum.