Research On Key Technology Of High-precision Methods Of Camera Calibration Based On Grid Nodes Extraction

With the advantages of non-contact,high-efficiency,high-precision,and convenient,image measurement has been gradually applied in industry,agriculture,aerospace,weapons guidance,etc.Camera calibration is an important part of the image measurement,and precise camera parameters is the precondition of the high precision measurement.This paper adopt an approach of calibration technique based on planar gridding plate,realize the high-precision calibration of camera.Based on neighborhood variation,this article uses the idea of minimizing the sum of the squares of the distances to improved Harris corner detection algorithm.This article uses the idea of iterative search to improve the corner detection algorithm based on quadric surface fitting.Simulation results show that the proposed approaches can extract positions of the grid nodes at pixel and Sub pixel level accurately.In the aspect of image distortion,the method based on intersection of gridline might obtain the relatively good results.This paper use Canny operator to extract the pixel level edge points as the high precision extraction of the initial value,improve an edge detection algorithm based on Gaussian curve fitting and vector-gradient-inner.Simulation results show that proposed methods can extract positions of the grid nodes at Sub pixel level accurately.This article uses aberration model of 5 factors derive expressions of grid line on the image,then obtain the intersection of fitting cure equations.In the real calibration experiment,the dissertation implemented the algorithm based on neighborhood variation and intersection of gridline.In comparison,experiment results show that the improved edge detection algorithm based on Gaussian curve fitting can extract positions of the grid nodes at a higher precision.