Binary spatiotemporal encoded method used for uneven fringes phase unwrapping

A binary spatiotemporal encoded method for uneven fringes phase unwrapping was proposed to remove the limitation of the existing non-uniform striped phase unwrapping method. From the standard non-uniform stripes cut off the phase reverse to cut off the phase line, the boundary line for binary coding and decoding.By using four step phase shifting method, the absolute phase of deformed uneven fringes can be obtained with three pieces of aided coding patterns. The nonholonomic system was established, and the relationship between the absolute phase and the depth of the object was fitted by quadratic polynomial. Compared with existing methods in simulation environment, the improved amount of average and standard deviation of all symmetric points height difference of arch object are 65% and 51% respectively. The improved amount of average and standard deviation for arch cuboid are 95% and 90% respectively. At the same time, the method is used to measure the surface of the rectangular object, which average error is only 0.64%, compared with the measurement results of the Coordinate Measuring Machine(CMM). The experimental results show that the method can improve the quality of uneven fringes phase unwrapping, and improve the measurement accuracy under the condition that the number of aided coding pattern is not increase.