An affine transform center line extraction and discontinuity deviation correction method for non-orthogonal grid laser

Abstract

The extraction of the laser center line is one of the key steps of laser scanning, which is related to the accuracy of the coordinate calculation. Non - orthogonal grid laser scanning has the advantages of a large measuring range and small translation error. For the extraction of the center line of the laser cross region of non-orthogonal grid, the discontinuity and deviation of the results obtained by the existing methods will cause the error of center line coordinate extraction. To solve these problems, according to the properties of image affine, an improved method of laser center extraction for non-orthogonal grid is proposed in this paper. Firstly, the image is cut into sub-images for affine transformation to become orthogonal grid laser images. Secondly, to solve the discontinuity problem of the center line, the orthogonal grid laser image was rotated 90° from the original image, and the Steger method was used for processing. Inverse affine transformation is performed on the results. Finally, the sub-image is cut according to the slope, and then the center line is obtained by concatenation and union. By comparing various methods and 3D reconstruction experiments, the accuracy of the proposed method is verified in the center line extraction of grid laser cross-region.