Research On The Phase Error Compensation And Hole-Repairing Of Optical 3D Shape Measurement

With the development of techniques, in recent years, grating projection three-dimensional measurement technology is mature and tend to move towards more areas. The grating projection three-dimensional measurement technology has non-contact, high efficiency, high precision, etc., to gradually replace the contact measurement, become a hot research on the field of measurement technology. The grating projection three-dimensional measurement technology has been widely used in reverse engineering, industrial inspection, medical diagnostics, heritage digitization and garment manufacturing and other fields.The grating projection three-dimensional measurement technology projects a grating strip onto the surface of measurd thing by a digital projection equipment (DLP), generally use the standard sinusoidal gratings, the image of distorted grating stripn modulated things surface hight is collected by the image sensor, through the gray of image to solve object phase, and then calculate 3D point cloud data of the measured object. Based on the principles and key technical systems analysis, the phase error and holes patched in-depth study, to build a three-dimensional measurement system. Main work can be divided as follows:Firstly, to research the principle and the need for technology of the system, such as camera calibration, phase strike, system calibration and so on. Campare the traditional measurement model with the new measurement model, analyze their strengths and weaknesses, to identify new system model for the present model.Secondly, to research the consideration and expansion of phase, compare gray code with binary coding, to analyse the problem of the point cloud stratification, Adoption and innovation of grating complementary coding which is suitable for the system. The problem of phase cycle dislocation can be solved, and then solve the problem of stratification.Thirdly, to compensate for the phase error, the presence of phase error will result in the significant of measurement error, and created phase error lookup table which is suitable for the system, phase error compensation can be used in system calibration and subsequent measurements.Finally, to research the problem of point cloud hole, hole boundary feature points are identified, links, establish characteristic plane polygon angle calculation for holes, it is suitable for flat and similar to the plane of the holes patched.