A direct calibration method for line structured light measurement system based on parallel lines

In view of the complexity of the traditional calibration methods for the line structured light measurement system, this paper proposes a direct system calibration method and corresponds to a direct calibration model. This method adopts a planar target to create the feature lines and uses the moving distance of linear guide as constraints, which can determine the mathematical relationship between the pixel and world coordinates directly. Compared with traditional calibration models, the proposed model does not need to consider the spatial structure of this system and calibrate each component separately, which simplifies the calibration process and reduces accumulative errors. Furthermore, the target used in this approach can be an ordinary plane, which avoids the difficulty of manufacturing special targets. Experimental results show that the root mean square error (RMSE) is 0.0238 mm and the mean absolute error (MAE) is 0.0255 mm, which can be used for industrial measurement more effectively.