Method for reducing enhancement of artifacts and noise in image color enhancement

• US 20070172118A1
• Filed: 03/30/2006
• Published: 07/26/2007
• Est. Priority Date: 01/24/2006
• 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: Pan, Hao
• Granted Patent: US 8,121,401 B2
• Time in Patent Office: Days
• US Class Current: 382/162
• CPC Class Codes: H04N 1/58 Edge or detail enhancement; Noise or error suppression, e.g. colour misregistration correction H04N1/62 takes precedence

Abstract

A method for enhancing the color of an image to be displayed on a display includes receiving an image having a plurality of pixels where each of the pixels has a plurality of color components. The image is filtered using a spatial filter in such a manner that the lower frequency content of the image is enhanced in such a manner that the dynamic range of the lower frequency content is increased. The filtered image is modified such that the higher frequency content of the image to obtain a modified image that includes the higher frequency content and the lower frequency content.

Claims

1. A method for enhancing the color of an image to be displayed on a display comprising:

(a) receiving an image having a plurality of pixels where each of said pixels has a plurality of color components;

(b) filtering said image with a spatial filter in such a manner that the lower frequency content of the image is enhanced in such a manner that the dynamic range of said lower frequency content is increased;

(c) modifying said filtered image with the higher frequency content of said image to obtain a modified image that includes said higher frequency content and said lower frequency content.

2. The method of claim 1 wherein said lower frequency content is defined by a low pass filter.

3. The method of claim 1 wherein said lower frequency content includes edges.

4. The method of claim 1 wherein said lower frequency content is defined using a sigma filer.

5. The method of claim 1 wherein said spatial filter includes a region defined around a pixel of interest.

6. The method of claim 5 wherein said spatial filter determines pixels within said region that are sufficiently similar to said pixel of interest.

7. The method of claim 1 wherein said image is separated into a base image and a residual image, said base image is said filtered and said residual image includes said higher frequency content.

8. The method of claim 1 wherein said lower frequency content contains sharp edges.

9. The method of claim 1 wherein said higher frequency content includes high frequency details, noise, and artifacts.

10. The method of claim 1 wherein said filter includes a threshold.

11. The method of claim 1 wherein said threshold is based upon the content of said image.

12. A method for enhancing the color of an image to be displayed on a display comprising:

(a) receiving an image having a plurality of pixels where each of said pixels has a plurality of color components;

(b) filtering each of said color components of said plurality of components with a sigma filter to obtain a base image wherein said base image is characterized by having primarily low frequency components of said image;

(c) modifying said input image based upon said base image to obtain a residual image wherein said residual image is characterize by having primarily high frequency components of said image;

(d) filtering said base image with a pixel-based color enhancement technique to obtain an enhanced base image in such a manner that the dynamic range of said base image is increased;

(e) modifying said enhanced base image based upon said residual image to obtain an enhanced image that includes said high frequency content of said image.

13. The method of claim 12 wherein said residual image is further processed using a decontouring technique.