正弦条纹打在三维物体上，CCD记录到的条纹由于受到三维物体高度的调制而发生扭曲，扭曲的条纹（deformed fringe）实质上为原始条纹在物体具有高度存在的位置有了附加相位，各点的相位表现为由CCD图像采集获得的被调制的条纹数字图像的灰度值。通过扭曲的条纹和原始条纹比对计算得出相位变化值。(Sinusoidal fringe strikes a three-dimensional object, and the fringes recorded by CCD are distorted due to the modulation of the height of the three-dimensional object. The deformed fringe essentially has an additional phase for the position where the original fringe exists at the height of the object. The phase of each point is shown as the gray value of the digital image of the modulated fringe acquired from the CCD image. The phase change is calculated by comparing the twisted fringes with the original fringes.)