窗口傅里叶变换的三维面形测量

由于窗口傅里叶变换具布局部分析特性，且局部谱比全局的谱更简单、更不容易频谱混叠。本文提出在基于频谱分析的三维面形测量中，用窗口傅里叶变换（WFT）代替传统的快速傅里叶变换（FFT）去获取三维物体面形分布。理论分析和实验结果表明：窗口傅里叶变换不但可以减小频谱混叠对测量精度的影响，并且若在窗口傅里叶变换的处理过程中，设置合理的“门限”，还能够有效的抑制噪声。从而在一定程度上保证了基于频谱分析的三维面形测量的精度。

Windowed Fourier transform for 3 - D shape measurement

Based on the local analysis characteristic of Windowed Fourier transfo rm(WFT),The spectrum of partial fringes formed by scanning the whole fringe pattern by a window function is simpler and less-aliasing than that of a whole fringe.A WFT method is introduced to retrieve the 3-D shape of the tested object,Instead of the traditional Fourier transform profilometry in this paper.We give the theoretic analysis and carry out the experiment to verify our theory. It shows that the WFT method can not only reduce the influence of frequency aliasing to guarantee the measurement precision,But also eliminate noise more effectively if a suitable threshold is selected during WFT processing.