Determining digitizing distances on sculptured surfaces using short time Fourier transform

Surface digitization is a method for obtaining three-dimensional measurement of an unknown surface. The performance and quality of digitization are dependent upon the choice of digitizing devices and approaches. An efficient digitizing method not only reduces the elapsed time of the digitizing process, but also improves the precision of measurement. This paper presents a new nonuniform technique for digitizing of sculptured surfaces based on the short time Fourier transform (STFT). The digitizing distances in the x and y directions for each pre-divided block of the surface are adjusted according to the highest spatial frequencies contained in the block which is in contrast to the uniform technique in which the digitizing distance is determined according to the highest spatial frequencies of the entire surface. The speed of the digitizing process is thus improved and meanwhile the accuracy of the surface representation is maintained. Simulations and experimental results are provided to verify the proposed method