Method and circuit for detecting edge of fixed pattern
First Claim
1. A method for detecting an edge of a fixed pattern, comprising:
- receiving a current input image;
receiving a history image and a corresponding history edge information;
adding the current input image and the history image according to a weight ratio to obtain a current analyzing image;
calculating an edge strength value of each pixel of the current analyzing image, wherein the edge strength value is calculated based on a predetermined condition of edge characteristic, and when the edge strength value is greater than a predetermined value, the pixel is a possible edge pixel, the current analyzing image is taken as the history image for next edge detection and analysis, and the edge pixel and the edge strength are recorded in the history edge information;
calculating a consistent pixel number that meets a predetermined consistent condition and an inconsistent pixel number that meets a predetermined inconsistent condition for the edge pixel of the current analyzing image and the edge pixel of the history image; and
when the consistent pixel number is greater than a first predetermined value and meanwhile the inconsistent pixel number is less than a second predetermined value, detecting the current input image having a fixed pattern with a fixed edge.
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Abstract
Method for detecting edge of fixed pattern includes receiving and analyzing a first image to obtain a first edge information. Second image and a corresponding second edge information are received, in which the second image includes an accumulation of image history information. According to the first edge information and the second edge information, a consistent number and an inconsistent number for pairs of pixels at the corresponding location of the first image and the second image are calculated, in which the consistent number represents how many pairs of pixels of which two compared pixels of each pair are both edge pixels, and the inconsistent number represents one of the two compared pixels is not the edge pixel. When the consistent number is greater than first predetermined value and meanwhile the inconsistent number is less than second predetermined value, first image and second image have a fixed pattern with fixed edge.
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Citations
15 Claims
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1. A method for detecting an edge of a fixed pattern, comprising:
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receiving a current input image; receiving a history image and a corresponding history edge information; adding the current input image and the history image according to a weight ratio to obtain a current analyzing image; calculating an edge strength value of each pixel of the current analyzing image, wherein the edge strength value is calculated based on a predetermined condition of edge characteristic, and when the edge strength value is greater than a predetermined value, the pixel is a possible edge pixel, the current analyzing image is taken as the history image for next edge detection and analysis, and the edge pixel and the edge strength are recorded in the history edge information; calculating a consistent pixel number that meets a predetermined consistent condition and an inconsistent pixel number that meets a predetermined inconsistent condition for the edge pixel of the current analyzing image and the edge pixel of the history image; and when the consistent pixel number is greater than a first predetermined value and meanwhile the inconsistent pixel number is less than a second predetermined value, detecting the current input image having a fixed pattern with a fixed edge. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detecting an edge of a fixed pattern, comprising:
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receiving and analyzing a first image to obtain a first edge information; receiving a second image and a corresponding second edge information, in which the second image comprises an accumulation of image history information; according to the first edge information and the second edge information, calculating a consistent number and an inconsistent number for pairs of pixels at the corresponding location of the first image and the second image, wherein the consistent number represents how many pairs of pixels of which two compared pixels of each pair are both edge pixels, and the inconsistent number represents one of the two compared pixels is not the edge pixel; and when the consistent number is greater than a first predetermined value and meanwhile the inconsistent number is less than a second predetermined value, the first image and the second image have a fixed pattern with a fixed edge. - View Dependent Claims (8, 9, 10)
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11. A circuit for detecting an edge of a fixed pattern, comprising:
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an image overlapping unit, for receiving and storing a current input image and a history image and a corresponding history edge information, wherein the current input image and the history image are added according to a weight ratio to obtain a current analyzing image; an edge detecting unit, for calculating an edge strength value of each pixel for the current analyzing image, wherein the edge strength value is calculated based on a predetermined condition of edge characteristic, and when the edge strength value is greater than a predetermined value, the pixel is a possible edge pixel, wherein the current analyzing image is taken as the history image for next edge detection and analysis, and the edge pixel and the edge strength are recorded in the history edge information; and a fixed pattern detecting unit, for calculating a consistent pixel number that meets a predetermined consistent condition and an inconsistent pixel number that meets a predetermined inconsistent condition for the edge pixel of the current analyzing image and the edge pixel of the history image, wherein when the consistent pixel number is greater than a first predetermined value and meanwhile the inconsistent pixel number is less than a second predetermined value, the current input image is detected to have a fixed pattern with a fixed edge. - View Dependent Claims (12, 13, 14, 15)
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Specification