傅里叶变换轮廓术中新的相位及高度算法分析

在传统傅里叶变换轮廓术三维面型测量中,为了准确得到被测物体的高度分布,必需保证投影仪出射光瞳和摄像机入射光瞳的连线与参考面平行并且在同一水平面,否则存在较大的误差。着眼于更普通的情况,讨论双瞳连线与参考面成某一夹角时的高度计算,推导出了非平行时的参考面光场及物面变形条纹光场的表达式,并给出了高度映射公式。因而,传统的傅里叶变换轮廓术测量成为角度α=0时的特例。该方法使傅里叶变换轮廓术的测量条件得到了放宽;易于通过移动投影装置或成像装置获取全场条纹;并为在难以实现双瞳与参考面平行的特殊环境下的测量提供了可行的方法。计算机模拟及实验均证实了该方法的有效性。

Analysis of New Phase and Height Algorithm in Fourier Transform Profilometry

In order to obtain a correct height distribution of a measured object using the conventional Fourier transform profilometry(FTP), the connecting line between the exit pupil of the projecting system and entrance pupil of the imaging device must parallel to the reference plane and in the same horizontal.Otherwise,severe error will be introduced.We propose a new height calculation method in Fourier transform profilometry for the case of nonparallel,deduce the expression of the reference fringe and deformed fringe,and then obtain the phase-height mapping formula.As a result,we find that the conventional Fourier transform profilometry method,in which the projector and CCD camera are at the same height,is a special example of our method.The new method improved the flexibility in Fourier transform profilometry.It is easier to obtain the full-field fringes through moving either the projector or the camera.Therefore the height distribution in the case that the projector and camera are not at the same height.Both computer simulations and experiments have proved our methods.