Artifact removal method and system for contoured images and video

• US 9,042,644 B2
• Filed: 01/27/2014
• Issued: 05/26/2015
• Est. Priority Date: 03/19/2012
• Status: Active Grant

• Current Assignee: Cinova Media
• Original Assignee: Cinova Media
• Inventors: Mendhekar, Anurag, Sanghavi, Sunil
• Primary Examiner(s): Alavi, Amir
• Application Number:
  US14/165,467
• Publication Number:
  US 20140140618A1
• Time in Patent Office: 484 Days
• Field of Search: 382/167, 382/254, 382/274, 382/275, 375/240.03, 375/240.2, 375/240.21, 375/240.26, 348/607, 348/E5.078
• US Class Current: 382/167
• CPC Class Codes: G06T 2200/12 involving antialiasing
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 5/70 Denoising; Smoothing
• CPC Class Codes: G06V 10/30 Noise filtering
• CPC Class Codes: H04N 19/86 involving reduction of coding artifacts, e.g. of blockiness

Abstract

A system and method that reduce or eliminate step-contouring generated by compression algorithms are provided because many types of compression algorithms introduce a step-contoured artifact for images and video with slow gradients. The system and method restores the gradient to a piece of content by detecting a start and end of the step contour in each row and column of the piece of content and increments a pixel in certain regions of the row or the column to restore the gradient in the piece of content.

Claims

1. A system for removing a compression artifact from an original piece of content, the system comprising:

an artifact removal unit implemented on a computer system that restores a gradient to a piece of content by removing a step contour artifact; and

the artifact removal unit detects a start of a step contour and an end of a step contour in each row of the piece of content or each column of the piece of content, determines a gradient of the step contour in each row or each column and increments a pixel in certain regions of the row or the column to restore the gradient in the piece of content.

2. The system of claim 1, wherein the artifact removal unit increments the pixel in a certain region of the row or the column by multiplying a position of the pixel relative to a start of the row or column by a determined gradient for the row or column.

3. The system of claim 1, wherein the artifact removal unit detects the start of the contour by detecting a first pair of pixels scanned with a difference of one of N and 0.

4. The system of claim 1, wherein the artifact removal unit detects the end of the contour by detecting a first pair of pixels where the difference the pixels is one of Not 0 or N and a direction of the difference has changed.

5. The system of claim 1, wherein the artifact removal unit further comprises a plurality of lines of computer code.

6. The system of claim 1, wherein the piece of content is one of an image, a color image and a video frame.

7. The system of claim 6, wherein the color image is an image for each color that makes up the color image.

8. The system of claim 6, wherein the video frame is a series of images.

9. A method for removing a compression artifact from an original piece of content, the method comprising:

detecting a start of a step contour and an end of a step contour in each row or column of the piece of content;

determining a gradient of the step contour in each row or column; and

incrementing a pixel in certain regions of the row or column to restore the gradient in the piece of content.

10. The method of claim 9, wherein incrementing the pixel in certain region of the row or column further comprising multiplying a position of the pixel relative to a start of the row or column by a determined gradient for the row or column.

11. The method of claim 9, wherein detecting the start of the contour further comprises detecting a first pair of pixels scanned with a difference of one of N and 0.

12. The method of claim 9, wherein detecting the end of the contour further comprises detecting a first pair of pixels where the difference the pixels is one of Not 0 or N and a direction of the difference has changed.

13. The method of claim 9, wherein the piece of content is one of an image, a color image and a video frame.

14. The method of claim 13, wherein the color image is an image for each color that makes up the color image.

15. The method of claim 14, wherein the video frame is a series of images.