2维载频条纹傅里叶变换轮廓术

Grid fringe pattern Fourier transform profilometry

为了在3维形貌测量中解决非连续物体所存在的非连续相位解包问题并提高测量精度,提出采用2维网格光栅作为空间载频条纹的傅里叶变换轮廓术。首先应用2维傅里叶变换对2维光栅条纹图像进行频谱分析;然后设计带通滤波器分离出两个1维变形光栅条纹,在1幅变形网格光栅条纹得到两个1维光栅各自所对应的包裹相位分布;最后应用查表法进行解包得到确定的调制相位分布,给出了详细的理论推导和实验结果。结果表明,采用2维网格光栅+查表相位解包法很好地解决了1维单一频率光栅条纹的低测量精度、1维双频光栅的频率混叠以及3维测量中高度不连续所存在相位解包问题,该方法是可行的。

In order to increase measurement precision and overcome discontinuous phase unwrapping in the 3-D shape measurement of discontinuous objects, an improved Fourier transform profilometry（FTP） was presented with a grid fringe pattern as spatial carrier-fringes. Two 1-D deformed grating patterns were extracted from the deformed grid fringe pattern using 2-D Fourier transform and fixed bandwidth filters. Two wrapped phases were obtained from these both one-dimension deformed patterns, respeetively, and the corresponding unwrapped phases were achieved by means of a lookup table method. The experimental results show that the technique can overcome the low measurement precision using 1-D single frequency fringe pattern, the possible frequency overlaps using 1-D dual-frequency fringe pattern and tolerate the height discontinuity of the 3-D shape measurement; the above method is available.