Energy linear variation round mark point and extraction method

Abstract

The present invention belongs to the technical field of computer visual measurement and relate to an energy linear variation mark point and an accurate and stable mark point extraction method. The mark point is circular as a whole, the gray scale is linearly varied from the center to the edge, and the center has highest brightness and highest gray scale. The mark point extraction method comprises: firstly, performing crude extraction on the center of the mark point, and by utilizing the symmetry of a graph of the whole mark point, performing crude extraction with a gray-scale centroid method to extract a centroid of the mark point; secondly, performing elliptical cone fitting by using gray-scale linear information of the whole mark point rather than single boundary information; and thirdly, fitting out an optimal elliptical cone with a least square method to obtain precise center coordinates of an energy mark point. According to the energy linear variation round mark point and the extraction method, two extraction methods are used to ensure extraction precision; and compared with a conventional mark point, the energy linear variation round mark point and the fitting method have wider and preciser applications, and mark point extraction precision and robustness are improved.

Description

technical field [0001] The invention belongs to the technical field of computer vision measurement, and relates to a marker point related to energy linear change and an accurate and stable marker point extraction method. Background technique [0002] The visual measurement system based on computer vision theory is widely used in the manufacturing industry because of its advantages of non-contact, high measurement efficiency and high measurement accuracy. Among them, the design of marker points and their extraction methods play a very important role in machine vision. In many cases, marker points are the main objects of image acquisition, and marker point extraction is also the main step of image processing. With the continuous development of modern science and technology, the application of machine vision technology is more extensive, which makes the design of marking points and extraction methods must meet a wider range of requirements, and puts forward relatively stringent...

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Problems solved by technology

For example, Xie Zexiao, Gao Xiang, Cui Jian et al. published in China Laser in 2013 "Circular Marker Extraction Algorithm for Mobile 3D Measurement" uses circular markers with white bright circles inside and black circles around them to extract Only some points on the intersection line of the white inner circle and the black outer circle, the extracted image information and constraints are very limited, and the accuracy of the center of the circle cannot be guaranteed

"AFlexible New Technique for Camera Calibration" published by Zhang Zhengyou and others on IEEETRANSACTIONSONPATTERNANALYSISANDMACHINEINTELLIGENCE in 1988 uses a checkerboard calibration target for calibration, which guarantees the accuracy very well. However, in the operation process, it is necessary to manually specify the intersection range of the checkerboard grid, and then perform corner search. Complicated and less intelligent

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