Beer bottle opening positioning method based on multi-time random circle detection and fitting degree assessment

The invention discloses a beer bottle opening positioning method based on multi-time random circle detection and fitting degree assessment. The method is composed of two parts: edge point obtaining and circle detection. The concrete steps are that firstly, outer edge points of a bottle opening are obtained through threshold segmentation, gravity center calculation and radial scanning; secondly, a random circle is determined through three points sampled from the outer edge points of the bottle opening randomly; thirdly, a ratio of number of the outer edge points with distances to the random circle being less than a given threshold to edge point total number is employed as a circle fitting degree of the random circle and a fitting degree is calculated; fourthly, the second step and the third step are carried out repeatedly until the situation that number of circle detection or total number of three-point random circle detection reaches the given threshold is achieved successfully; fifthly, the maximum fitting degree is searched, and the circle center of the random circle corresponding to the maximum fitting degree is employed as the center of the bottle opening. The method solves the problem effectively that a present beer bottle opening positioning method has great positioning errors when a bottle opening is damaged seriously or illumination is uneven.