Zero spectrum removal using joint bilateral filter for Fourier transform profilometry

Traditional Fourier transform profilometry (FTP) removes the zero spectrum of the acquired fringe image using the linear filtering approach. Such approach assumes there is no aliasing between the zero spectrum and the higher harmonics of the image, which however is not true in general. Thus it cannot adapt to sharp illuminant changes in the fringe image. One practical solution is to exploit one more fringe pattern with π phase shift to eliminate the zero spectrum. This however complicates the system in that the projection of the fringe patterns should be synchronized with the capturing device. Motion or imperfect synchronization makes the subsequent 3D reconstruction erroneous. In this paper, we introduce a 2D joint bilateral filter to help in removing the zero spectrum. Since the bilateral filter is sensitive to abrupt changes in the fringe image, we can accurately extract the zero spectrum even if there are sharp spatial variations in the pixel magnitude. Experimental results show that the proposed algorithm is superior to the traditional methods and facilitate accurate reconstruction of objects´ 3D model.