A research on the correction method of Two-dimensional bar code distortion on free radius cylindrical surface

摘要

In order to solve the recognition problem caused by the distortion of two-dimensional bar code printed directly on the cylindrical units, a correction method has been put forward based on the combination of the information of space geometry calibrated in the camera and that of the image. Firstly, we should obtain the fixed parameters relating to the machine vision and then analyze how the two-dimensional bar code distorts on the cylindrical surface to find the correction method reversely. Since the cylindrical units vary from each other, it would be difficult to calibrate the radius of the units. Only by analyzing the perspective projection of the edge of the two-dimensional bar code on cylindrical surface and then founding the estimating function of radius can the parameters of radius be obtained from the image information. At last, the rationality of the algorithm is proved by experiments.