Fast and accurate 3D reconstruction based on grating projection

Abstract

The principle model and calibration method of measurement are very important to the measurement system. In the vision measurement system, the auxiliary light source, such as laser, interference light, sine grating and so on, is usually needed in order to achieve high precision measurement results. In the existing 3D measurement methods for the surface topography of complex objects, in order to complete the measurement of absolute phase, it is usually necessary to process at least 6 fringe images, which limits the measurement speed. A method for obtaining the 3D shape of an object by using four sinusoidal fringes is presented. The truncated phase of the sinusoidal fringe is obtained by using the four-step phase shift. When the fringe order is obtained, the time of data processing can be reduced and the measurement speed can be further improved. The reconstruction time is less than two minutes and the maximum absolute error and maximum RMS error are 0.033mm and 0.029mm respectively when the height of the face model is 45mm. The validity and practicability of the method are verified, and it has a wide application prospect in high-speed and real-time 3D measurement of complex topography.