The iterative 2D windowed Fourier transform: A SOS approach to speckle noise reduction in digital holography

摘要

This paper addresses the problem of the reduction of speckle noise corrupting phase images from laser digital holography technique. It present an iterative denoising algorithm based on the 2-D windowed Fourier Transform. The algorithm is a new approach based on the SOS procedure recently proposed by Y. Romano and M. Elad adapted to phase processing. The approach is proposed in the case of the 2-D windowed Fourier Transform algorithm applied to phase maps which constitutes the state of the art in the field of digital holography. The reason is that the sum and difference operations used in the SOS procedure cannot be computed directly on phase maps but using a sine and cosine representation in order to avoid 2n phase jumps. Results on simulated phase maps including realistic noise conditions encountered in digital holography show the advantage of the proposed iterative approach. The paper proposes the application of the method to denoising of phase images from digital three color holography applied to cracks characterization of a composite materiel under mechanical strength test.