Method and apparatus for extracting circular luminous spot second-pixel center

An extraction method and sub-pixel technology, applied in the field of image processing, can solve the problems of long extraction time and large amount of calculation

Inactive Publication Date: 2009-04-15
BEIHANG UNIV
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Problems solved by technology

Although the extraction accuracy of the Gaussian surface fitting method is high, it is usually necessary to perform Gaussian convolution on the larger neighborhood of the circular spot before performing Gaussian surface fitting on the pixel grayscale, so as to eliminate the irregular shape of the circular spot. The influence of rules on Gaussian surface fitting, so the calculation is large and the extraction time is long

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  • Method and apparatus for extracting circular luminous spot second-pixel center
  • Method and apparatus for extracting circular luminous spot second-pixel center
  • Method and apparatus for extracting circular luminous spot second-pixel center

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Embodiment Construction

[0028] In the solution provided by the present invention, at first utilize the centroid method to determine the initial position of the center of the circular light spot; then in a window centered on the initial position, determine the pixel of the center of the circular light spot according to the eigenvalue of the Hessian matrix position; finally, the second-order Taylor expansion is used to determine the image grayscale function continuously distributed in the neighborhood of the pixel position in the center of the circular spot. The extreme point position of the image grayscale function is the sub-pixel position in the center of the circular spot.

[0029] figure 1 It is a flowchart for extracting the sub-pixel center of the circular light spot in the present invention, such as figure 1 As shown, the extraction process of the sub-pixel center of the circular spot includes the following steps:

[0030] Step 101: Utilize the centroid method to determine the initial position...

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Abstract

The invention discloses a method for extracting circular facula sub-pel center and a device thereof. In the proposal of the invention, firstly, the initial position of the circular facula center is determined by utilizing a center of mass method; then, the pel position of the circular facula center is determined in a window by taking the initial position as a center according to the characteristic value of Hessian matrix; finally, image gradation function which is continuously distributed in a neighborhood of the pel position of the circular facula center is determined by using second order taylor expansion, and the position of extreme point of the image gradation function is the sub-pel position of the circular facula center. The searching range of the circular facula center is narrowed to a smaller area fast by the proposal of the invention, thus leading the follow-up operation such as gauss convolution, the calculation of S and the searching of the extremum to be carried out in the smaller area, and the calculated amount is small and the extracting speed is rapid. Therefore, the sub-pel position of the circular facula center is determined by the taylor expansion and the extracting precision of the circular facula center is ensured.

Description

technical field [0001] The invention relates to image processing technology, in particular to a method and device for extracting the center of a circular light spot sub-pixel. Background technique [0002] Spot extraction is an important link in the calibration and measurement process of the 3D visual inspection system. In order to ensure the accuracy and stability of the measurement system, the extraction accuracy of the spot is required to be at the sub-pixel level. Circular spot is widely used in extraction, because its unique circular shape is easy to identify and extract, and the extraction accuracy is relatively high. The traditional circular spot sub-pixel extraction methods mainly include: edge fitting method and Gaussian surface fitting method. [0003] One implementation of the edge fitting method is to use the Canny operator to extract the edge of the circular spot, and perform least squares ellipse fitting on the edge of the circular spot to obtain the center of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/60G01B11/00
Inventor 张广军杨珍孙军华刘谦哲吴子彦
Owner BEIHANG UNIV
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