A large-capacity, robust coded marker and its decoding method

Abstract

The invention relates to coding sign points high in capacity and high in robustness. The coding sign points comprise a positioning sign position, an initial sign position and coding positions. The initial sign position and the coding positions are evenly distributed on a circle the center of which is the positioning sign position. The positioning sign position is equipped with a positioning sign point. The initial sign position is equipped with an initial sign point. The coding positions are equipped with coding points. Different coding sign points are formed by a situation whether the coding points are arranged in the coding positions or not. The positioning sign point, the initial sign point and the coding points form a circle, and can be differentiated from each other in area. Compared with the prior art, the coding sign points have the beneficial effects that: 1, sign positions are easy to identify; 2, the coding capacity is high; 3, the coding positions that are on the same line with the positioning sign position and the initial sign position are equipped with the coding points, and the included angle between every two adjacent coding points is less than 180 degrees, so the uniqueness of angle identification is exhibited and the identification accuracy is improved; and 4, the decoding accuracy is greatly improved.

Description

technical field [0001] The invention relates to the technical field of close-range photogrammetry, and more specifically, to a large-capacity, robust coded marker point and a decoding method thereof. Background technique [0002] Coded marker points are generally used for three-dimensional measurement of large workpieces. In order to accurately measure the three-dimensional coordinates of large workpieces, a large number of coded marker points are often required. In the prior art, ring-coded marker points are often used in the photogrammetry of large workpieces, but the following problems exist in the actual use of ring-coded marker points: [0003] 1. The width of the coding band is different: when the coding band is longer, the recognition accuracy rate decreases; a single coding bit is easily misidentified as a positioning circle; [0004] 2. There is no unique start flag, and the encoding capacity is small: based on the invariance of photography, each bit of the code ba...

AI Technical Summary

Problems solved by technology

[0003] 1. The width of the coding band is different: when the coding band is longer, the recognition accuracy rate decreases; a single coding bit is easily misidentified as a positioning circle;

[0004] 2. There is no unique start flag, and the encoding capacity is small: based on the invariance of photography, each bit of the code band can be used as the start flag, and the minimum value of all possible values ​​is generally selected as the only start flag. When decoding, it is necessary to cycle through the comparison to get the minimum value, which increases the decoding calculation time. At the same time, since the start flag is not uniquely determined, when the value of the start flag is relatively large, its encoding capacity is small

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