Adaptive design of ideal low-pass filter based on Fourier-transform spectrum distribution of digital speckle interference fringe patterns by using edge-detection, morphological-operation, and Radon-transform algorithms

摘要

An adaptive method is proposed in this paper for design of an ideal low-pass filter based on the Fourier-transform spectrum distribution of digital speckle interference fringe patterns. The size and shape of the ideal low-pass filter can be determined automatically by using an adaptive method based on the edge detection and morphological operation. The cutoff frequency of the ideal low-pass filter along arbitrary direction can also be determined automatically by using an adaptive method based on the Radon transform. The ideal low-pass filter designed in the paper can be used effectively for denoising of digital speckle interference fringe patterns in phase-shifting digital speckle pattern interferometry.