Fourier transform profilometry based on a projecting-imaging model.

In order to obtain the correct height reconstruction of a measured object, a projection lens and a camera lens must be placed at equal heights above the reference plane in the traditional Fourier transform profilometry (FTP) method. We propose an improved phase-height mapping formula based on an improved description of the reference fringe and the deformed fringe in FTP when the projection lens and the camera lens are not placed at equal height. With our method, it is easier to obtain the full-field fringe by moving either the projector or the imaging device. In some cases, where the required parallel condition cannot be met, the proposed method offers a flexible way to calculate the height distribution.