Method of motion detection using adaptive threshold

• US 8,077,926 B2
• Filed: 01/14/2009
• Issued: 12/13/2011
• Est. Priority Date: 01/14/2009
• Status: Expired due to Fees

• Current Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Original Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Inventors: Chen, Ying-Ru
• Primary Examiner(s): AZARIAN, SEYED H
• Application Number:
  US12/353,679
• Publication Number:
  US 20100177935A1
• Time in Patent Office: 1,063 Days
• Field of Search: 382/100, 382/103, 382/104, 382/106, 382/107, 382/117, 382/162, 382/168, 382/172, 382/173, 382/181, 382190-195, 382/209, 382219-224, 382/232, 382/254, 382/260, 382274-275, 382/276, 382/291, 382/305, 382/312, 375/240.12, 375/240.16, 737/15, 706/18, 706/20
• US Class Current: 382/107
• CPC Class Codes: G06T 2207/20012 Locally adaptive
• CPC Class Codes: G06T 7/136 involving thresholding
• CPC Class Codes: G06T 7/246 using feature-based methods, e.g. the tracking of corners or segments

Abstract

A method of motion detection using an adaptive threshold, adaptive for determining whether a plurality of target pixels in a current scan line are moving pixels or not, is provided. First, a first threshold is given for determining whether the target pixels in the current scan line are moving pixels. Then, a number of moving pixels in a previous scan line of the current scan line is calculated and determined whether larger than a second threshold. If the number of moving pixels is larger than the second threshold, the first threshold is adjusted by a decrement, and then whether the target pixels in the current scan line are moving pixels is determined by using the adjusted first threshold.

Claims

1. A method of motion detection using an adaptive threshold, adaptive for determining whether a plurality of target pixels are moving pixels or not, the method comprising:

giving a first threshold for determining whether the target pixels in a current scan line are moving pixels, wherein the first threshold has an upper limit and a lower limit;

calculating a number of moving pixels in a previous scan line of the current scan line;

determining whether the number of moving pixels is larger than a second threshold;

if the number of moving pixels is larger than the second threshold, adjusting the first threshold by a decrement; and

determining whether the target pixels in the current scan line are moving pixels by using the adjusted first threshold,

wherein after the step of giving the first threshold, the method further comprises;

adjusting the first threshold by an increment when the motion detection of every L scan lines is completed, wherein L is a positive integer.

2. The method for motion detection using a content adaptive penalty function according to claim 1, wherein the first threshold is set as the upper limit when the adjusted first threshold is larger than the upper limit.

3. The method for motion detection using a content adaptive penalty function according to claim 1, wherein the first threshold is set as the lower limit when the adjusted first threshold is smaller than the lower limit.

4. The method for motion detection using a content adaptive penalty function according to claim 1, wherein after the step of determining whether the target pixels in the current scan line are moving pixels by using the adjusted first threshold, the method further comprises:

recording a result of motion detection of the target pixels in the current scan line as a reference for calculating the number of moving pixels when performing motion detection on a next scan line.

5. The method for motion detection using an adaptive threshold according to claim 1, wherein the step of determining whether the target pixels in the current scan line are moving pixels by using the adjusted first threshold comprises:

calculating a sum of a plurality of differences between the corresonding neighboring pixels of each of the target pixels in adjacent fields;

comparing the sum with the adjusted first threshod to determine whether the target pixel is the moving pixel.

6. The method for motion detection using an adaptive threshold according to claim 5, wherein the step of comparing the sum with the adjusted first threshod to determine whether the target pixel is the moving pixel comprises:

determining the target pixel as the moving pixel if the sum is larger than the first threshold; and

determining the target pixel as a static pixel if the sum is not larger than the second threshold.