A new method for eliminating background signal in Fourier transform profilometry by using images of object and reference plane is proposed. In comparison with the phase-shifting method, the proposed method employs the same number of grating projections and is less affected by jitter from LCD projector. Experimental verifications of the height reconstruction by using the proposed method is in agreement with that by using the direct contact method.
3-D shape reconstructions by using Fourier transform profilometry via a first-order derivative of Gaussian and Morlet wavelet are experimentally studied. The advantage of using the wavelet filters is that they have the same shape in the spatial and the spectra domains. Experimental results show that Morlet wavelet gives better shape reconstruction, because its transfer function is well localized.
A new method for eliminating unwanted background of Fourier transform profilometry (FTP) by using simple dc bias and background eliminations from the deformed grating images is proposed. The proposed method has an advantage over a conventional FTP in that the 3-D object profile can be accurately measured although original fundamental spectra are corrupted by a zeroth-order spectrum. Experimental verifications of the proposed method are presented.