Accurate and robust calibration method based on pattern geometric constraints for fringe projection profilometry.
In fringe projection profilometry, the relationship between phase and height is of the utmost significance to perform accurate measurement. To enhance accuracy and robustness, a calibration method is presented based on pattern geometric constraints. By analyzing the pattern distribution in the image coordinate, this method establishes a one-to-one mapping relationship between phase and height directly, and the lens distortion of the camera is considered and involved in the mathematical description, so as to eliminate error propagation. The (x, y) coordinates are calculated from camera calibration with known height values. This method is practical for the reason that strict system constraints are not needed and the calibration procedure is efficient. Experiments including error evaluation and robustness evaluation are conducted to verify its accuracy and robustness, respectively. The results reveal that this method has the desired properties of high accuracy and strong robustness. These performances guarantee its flexibility under different circumstances.