High dynamic range images from low dynamic range images

• US 20060104508A1
• 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 8,050,511 B2
• Time in Patent Office: Days
• US Class Current: 382/167
• CPC Class Codes: G06T 2207/20208 High dynamic range [HDR] image processing
• CPC Class Codes: G06T 5/92 based on global image properties
• CPC Class Codes: H04N 1/407 Control or modification of tonal gradation or of extreme levels, e.g. background level

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 dynamic range;

(b) modifying said image to a second dynamic range, wherein said second dynamic range is greater than said first dynamic range;

wherein said modification is based upon at least one of;

(i) said received image is in a substantially gamma domain and is converted to a substantially linear luminance domain prior to said modifying;

(ii) said modifying is further based upon processing at least two color channels of said image in a different manner;

(iii) said modifying based upon a function without discontinuities;

(iv) said modifying based upon a pair of piecewise linear functions;

(c) displaying said modified image a display.

2. The method of claim 1 wherein said received image is in said substantially gamma domain and is converted to said substantially linear domain prior to said modifying.

3. The method of claim 2 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 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.

4. The method of claim 3 wherein said first dynamic range is a first luminance dynamic range, and said second dynamic range is a second luminance dynamic range.

5. The method of claim 1 wherein said modifying is further based upon processing at least two color channels of said image in a different manner.

6. The method of claim 5 wherein said at least two color channels are compared to one another.

7. The method of claim 6 wherein said comparing occurs in a region outside of clipping.

8. The method of claim 1 wherein said modifying is based upon said function without discontinuities.

9. The method of claim 1 wherein said modifying is based upon said pair of piecewise linear functions.

10. The method of claim 5 wherein said first dynamic range is a first luminance dynamic range, and said second dynamic range is a second luminance dynamic range.

11. The method of claim 8 wherein said first dynamic range is a first luminance dynamic range, and said second dynamic range is a second luminance dynamic range.

12. The method of claim 9 wherein said first dynamic range is a first luminance dynamic range, and said second dynamic range is a second luminance dynamic range.

13. A method for displaying an image comprising:

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

(b) selectively modifying said image to a second dynamic range in a manner that amplifies specular highlights, wherein said second dynamic range is greater than said first dynamic range; and

(c) displaying said modified image a display.

14. The method of claim 13 wherein said modifying is free from modifying said image in a manner that said enhances said specular highlights.

15. The method of claim 13 wherein said modifying said enhances said specular highlights.

16. A method for displaying an image comprising:

(a) receiving an image;

(b) low pas filtering said image with a first low pass filter;

(c) determining a first substantial maximum of said image filtered with said first low pass filter;

(d) low pass filtering said image with a second low pass filter, where said second filter is larger than said first filter;

(e) determining a second substantial maximum of said image filtered with said second low pass filter;

(f) modifying said image based upon said first substantial maximum;

(g) modifying said result of said modifying of said image based upon said first substantial based upon said second substantial maximum;

(h) determining regions of said modified image as a result of said second substantial maximum to change a dynamic range of said image;

(i) modifying said image based upon said regions in such a manner as to increase the dynamic range of said image.

17. The method of claim 16 wherein said dynamic range is a dynamic luminance 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 the function for said modification is based upon said image, wherein said second dynamic range is greater than said first dynamic range;

(c) displaying said modified image a display.

19. The method of claim 18 wherein said function includes a maximum diffuse white.

20. The method of claim 18 wherein said function includes a variable slope.