时间相位展开方法投射一系列不同频率的条纹图到物体表面,然后将每点的相位在时间序列上独立进行展开,从而避免了误差的扩散,在近年来得到了很好的发展.本文对时间相位展开方法的效率、可靠性和精度之间的关系进行了研究和分析,并针对三种典型的时间相位展开方法:负指数拟合法,三频展开法和外差法,在上述三个方面作了定量计算和比较.根据几种方法的特点,提出了结合三频展开法和外差法优点的算法设计方法——三频外差法.计算机仿真和实验表明,该方法在仅使用三频条纹图的情况下,可以达到较高的可靠度和精度,应用前景比较好.
Temporal phase unwrapping method projects grating fringes with different pitches, the phase unwrapping process is then carried out for each pixel along the time axis independently, so as to avoid the error spreading, and has been developed well in recent years. This article researches and analyses on time efficiency, reliability and accuracy of phase unwrapping methods, compares above aspects of three typical temporal phase unwrapping methods: Fitting negative exponential, three pitches unwrapping and heterodyne method. According to the charateristics of those methods, we present a new algorithm disignment that combines the advantages of three pitches unwrapping and heterodyne method-three pitches heterodyne method. It is shown in computer simulation and experiment results that using only three grating fringes, the new method still has high reliability and accuracy, so it has a broad application prospect.