Efficient detection of constant regions of an image

• US 20070206861A1
• Filed: 03/06/2006
• Published: 09/06/2007
• Est. Priority Date: 03/06/2006
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Technology, Ltd. (Marvell Technology Group Limited)
• Inventors: Shoen, Jay
• Granted Patent: US 7,428,336 B2
• Time in Patent Office: Days
• US Class Current: 382/195
• CPC Class Codes: G06T 7/11 Region-based segmentation

Abstract

A technique that improves image analysis efficiency by reducing the number of computations needed to detect constant regions. Constant region detection according to the present techniques includes determining whether an image analysis window at a current position contains a constant region by analyzing a new line of pixels in the image analysis window if a pixel at a predetermined location in the image analysis window in the current position has a value equal to a pixel at the predetermined location from a previous position of the image analysis window. Analyzing only the new line of pixels saves the computational time that would otherwise go into analyzing all of the pixels in the image analysis window.

Claims

1. A method for detecting a constant region of an image frame, comprising:

shifting an image analysis window to a current position that includes a new line of pixels from the image frame in comparison to a previous position of the image frame;

determining whether the image analysis window at the current position contains the constant region by analyzing the new line of pixels if a pixel at a predetermined location in the image analysis window in the current position has a value equal to a pixel at the predetermined location from the previous position and analyzing all of the pixels in the image analysis window otherwise.

2. The method of claim 1, wherein the predetermined location is a center of the image analysis window.

3. The method of claim 1, further comprising detecting the constant region at the previous position of the image analysis window.

4. The method of claim 1, wherein analyzing the new line of pixels comprises comparing a set of values of the new line of pixels to a value of the pixel at the predetermined location.

5. The method of claim 1, wherein shifting the image analysis window comprises shifting the image analysis window by one pixel.

12. The device of claim 1, wherein the predetermined location is a center of the image analysis window.

13. The device of claim 1, wherein the image processor the constant region at the previous position of the image analysis window.

14. The device of claim 1, wherein the image processor analyzes the new line of pixels by comparing a set of values of the new line of pixels to a value of the pixel at the predetermined location.

15. The device of claim 1, wherein the image processor shifts the image analysis window by shifting the image analysis window by one pixel.

6. An image processing system including means for detecting a constant region of an image frame, comprising:

means for shifting an image analysis window to a current position that includes a new line of pixels from an image frame in comparison to a previous position of the image frame;

means for determining whether the image analysis window at the current position contains the constant region by analyzing the new line of pixels if a pixel at a predetermined location in the image analysis window in the current position has a value equal to a pixel at the predetermined location from the previous position and analyzing all of the pixels in the image analysis window otherwise.

7. The image processing system of claim 6, wherein the predetermined location is a center of the image analysis window.

8. The image processing system of claim 6, further comprising means for detecting the constant region at the previous position of the image analysis window.

9. The image processing system of claim 6, wherein the means for analyzing the new line of pixels comprises means for comparing a set of values of the new line of pixels to a value of the pixel at the predetermined location.

10. The image processing system of claim 6, wherein the means for shifting the image analysis window comprises means for shifting the image analysis window by one pixel.

11. A device, comprising:

image buffer that holds an image frame;

image processor that detects a constant region of the image frame by shifting an image analysis window to a current position that includes a new line of pixels from the image frame in comparison to a previous position of the image frame and determining whether the image analysis window at the current position contains the constant region by analyzing the new line of pixels if a pixel at a predetermined location in the image analysis window in the current position has a value equal to a pixel at the predetermined location from the previous position and analyzing all of the pixels in the image analysis window otherwise.