Phase unwrapping algorithm based on three-wavelength phase shift profilometry
Aiming at problems of low measurement speed and limited measurement range for method of multi-wavelength phase shift profilometry, a three-wavelength phase shift profilometry was presented to realize the measurement of color three-dimensional object with step change on surface. Direct problem of equivalent wavelength and wrapped phase of three-wavelength phase shift profilometry was introduced. Then, starting with the phase solution of the equivalent wavelength, and therefore phase unwrapping equations of three independent light waves were deduced. By analyzing phase noise generation reasons, phase denoising method based on unwrapping phase was presented. Experimental results show that average measurement accuracy of the method is 0.018 mm; processing time of ordinary desktop computer is 0.308 s. By comparing measurement precision, measurement speed, algorithm stability, range of adaptive light source and other performances, it is proved that the proposed method is more superior to the commonly used gray code methods and multi-wavelength phase shift profilometry at present.