Abstract: A new measurement model is proposed to solve this problem, in which the projector light field is regarded as the space swept by projection planes marked by their phase values, and the camera model is regarded as the collection of rays marked by their image coordinates, then the point on the measured part can be determined as the intersection point of corresponding projection plane and the image ray. Based on above analysis, the reverse method for solving the mathematic model of the projector is proposed, which has the benefit of avoiding calibrating projector explicitly. The radical and tangential lens distortion coefficients of the camera are solved by two separately separate steps, and then the camera model can be set up according to the pinhole image model. Enough calibration foundation data is collected by the planar target free location method, so the location and size of the target is no longer been restricted strictly, and the complete calibration result can still be fulfilled while the calibration data is not cover the entire view space. Benefits of our calibration method are that strict construction assembly requirement and accurate displacement device are no longer being needed, and the calibration error caused by lens distortion of both the projector and the camera can be eliminated effectively.

Key words: 3D reconstruction, Lens distortion, Phase measurement profilometry (PMP), System calibration