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Newton's theorem-based method for detecting ellipses in shot object images

A technology for capturing images and detecting ellipses, applied in image analysis, image data processing, instruments, etc., can solve problems such as time-consuming, inaccurate ellipse edge information, and misdetection of non-elliptical objects

Active Publication Date: 2018-07-31
ZHEJIANG UNIV
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Problems solved by technology

[0004] The above research has improved the effect of ellipse detection, but still faces the problems of false detection of non-ellipse targets, inaccurate ellipse edge information, and time-consuming problems.

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  • Newton's theorem-based method for detecting ellipses in shot object images
  • Newton's theorem-based method for detecting ellipses in shot object images
  • Newton's theorem-based method for detecting ellipses in shot object images

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Embodiment Construction

[0063] The present invention will be further described below in conjunction with accompanying drawing and example.

[0064] Embodiments of the present invention and its implementation process are as follows:

[0065] (1) Acquisition of target images containing elliptical elements, specifically implementing the acquisition of cylindrical objects or pure images with approximate ellipses.

[0066] First establish the image coordinate system, take the pixel point located in the upper left corner of the target image as the origin, horizontally to the right as the positive direction of the horizontal axis, and vertically downward as the positive direction of the vertical axis, and construct a plane Cartesian coordinate system.

[0067] Use the Canny edge detector to perform edge detection on the target image to obtain each arc, and use the pixel points on the arc as edge points, and obtain each edge point according to the gradient information calculated by the sobel operator in the ...

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Abstract

The invention discloses a Newton's theorem-based method for detecting ellipses in shot object images. According to the method of the invention, in a pre-processing stage, invalid edge information is removed according to arc dimension constraints; edge gradient information is extracted, the slope of each edge point is calculated, and edges are divided into four categories according to the slope information; arcs which satisfy a condition of constituting an ellipse are aggregated according to the relative positional relationships of endpoints and Newton's theorem-based geometric constraints; theleast squares method is directly adopted to estimate the parameters of arcs belonging to the same set; and the validity of fitted ellipses is verified, ellipses that do not satisfy a verification condition are removed, and ellipses requiring repeated detection are aggregated. Since a large number of invalid edges are removed, dimensions, relative positions and Newton's theorem-based geometric constraints are adopted, the precision and speed of ellipse detection are significantly improved.

Description

technical field [0001] The invention relates to an image detection method, in particular to an ellipse detection method in an object shot image based on Newton's theorem. Background technique [0002] Since ellipses are one of the most common geometric shapes, ellipse detection is a fundamental task in fields such as machine vision and pattern recognition. In recent years, the extraction of ellipse parameters has played an important role in technical fields such as camera calibration, pose detection, target segmentation, and iris recognition. At present, the existing ellipse detection algorithms have problems such as incomplete coincidence between the fitted ellipse contour and the actual contour, misdetection of non-ellipse targets, long detection time, and inability to meet the requirements of real-time detection. Therefore, fast and high-accuracy ellipse detection is still a challenging task. [0003] In 1996, in the paper "Direct least square fitting of ellipses" of "I...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T7/13G06T7/50
CPCG06T7/13G06T7/50
Inventor 段桂芳刘夏刘振宇谭建荣
Owner ZHEJIANG UNIV
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