High dynamic range images from low dynamic range images

• US 8,050,512 B2
• Filed: 09/22/2005
• Issued: 11/01/2011
• Est. Priority Date: 11/16/2004
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Repko; Jason M
• Assistant Examiner(s): Thirugnanam; Gandhi
• Application Number:
  US11/233,747
• Publication Number:
  US 20060104533A1
• Time in Patent Office: 2,231 Days
• Field of Search: 382/232, 382/254, 382/274
• US Class Current: 382/274
• 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, said method comprising:

(a) receiving an image having a low dynamic range into an apparatus capable of displaying said image;

(b) said apparatus having a processor that modifies said image to a high dynamic range free from being based upon other images, wherein said high dynamic range is greater than said low dynamic range, modification of said image comprising the steps of;

(i) partitioning pixels of said image into a diffuse luminance range of said low dynamic range and a specular luminance range of said low dynamic range, where said diffuse-luminance range is characterized by the inclusion pixels of said image primarily having the color of the respective objects displayed by said image, and said specular luminance range is characterized by the inclusion of pixels of said image having the color of a light source illuminating the respective objects displayed by said image;

(ii) rescaling pixels of said diffuse-luminance range of said low dynamic range to a diffuse luminance range of said high dynamic range using a first function linear in a luminance domain of the pixels of said image, in a manner free from rescaling pixels of said specular luminance range of said low dynamic range using said first function, where said diffuse luminance range of said high dynamic range is larger than said diffuse luminance range of said low dynamic range; and

(iii) rescaling pixels of said specular luminance range of said low dynamic range to a specular luminance range of said high dynamic range using a second function linear in a luminance domain of the pixels of said image, different than said first function, where said specular luminance range of said high dynamic range is larger than said specular luminance range of said low dynamic range and where said specular luminance range of said high dynamic range has a size automatically calculated as a function of a maximum diffuse white value received from said image; and

(c) displaying said modified image on said apparatus.

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

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

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

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

6. The method of claim 1 wherein said first function has a white point in said high dynamic range different than said second function.

7. The method of claim 1 wherein the lower boundary of said specular luminance range of said high dynamic range is based on the dynamic range capable of being displayed by said apparatus.