双色正弦投影傅里叶变换轮廓术方法研究

Study on Fourier transform profilometry by bicolor sinusoidal fringe pattern projection

提出双色正弦条纹投影方法来提高 FTP 的测量范围并保持其实时特点。只需采集一帧双色变形条纹,从中分离出两个有 π 位相差的分量,通过背景和对比度校正,得到一帧消零频的变形条纹图,并且自动生成物体轮廓的二元模板。此模板结合调制度信息相可以生成可靠性模板,指导相位展开,避免物体轮廓以外相位展开误差的传递;结合参考条纹可以完成变形条纹的扩充,提高频域的分辨率。

In order to improve the measuring range of Fourier Transform Profilometry (FTP) and maintain its instantaneous character, a method based on bicolor sinusoidal fringe projection is proposed, by which a bicolor sinusoidal fringe pattern consisting of two interlaced RGB format base color fringe patterns with π phase difference is projected onto the object thought digital light projector. After capturing the deformed color pattern, two individual sinusoidal fringe patterns with π phase difference can be decoded through color-separating technique. After accessing these two fringe patterns, zero order spectra can be eliminated and the binary template function will be automatically established to divide valid unwrapping area so as to prevent error transferring of unwrapping invalid area as well as to shorten the unwrapping time. Further more, using the mask function, the deformed fringe pattern captured can be easily expended to form a full field fringe pattern with certain measurement precision.