ADAPTIVE FILTER ALGORITHMS FOR INTERFERENCE PATTERNS OF DIFFUSION MEASUREMENTS

A holographic interferometer is used to measure diffusion coefficients of binary molten salt mixtures. The composition of such transparent m ixtures is proportional to the refractive index. The composition chang es cause local variations of the refractive index during diffusion. Th ese variations are visualized by interference fringes, which are photo graphed by a CCD camera. Exact detection of the intensity extreme valu es of the fringes is essential to calculate diffusion coefficients. As irregular illumination and noise disturb the detection, adaptive filt er algorithms are applied to reduce noise sufficiently while maintaini ng all relevant information. (C) 1997 Society of Photo-Optical Instrum entation Engineers.