ON THE USE OF DIFFERENT WAVELENGTHS TO DIGITALLY DETERMINE THE ISOCHROMATIC FRINGE ORDER

摘要

Four approaches, a novel, two modified and a previous developed approaches, are compared for the determination of the total fringe orders using different wavelengths. The results show that an error of 0.05 fringes can be achieved by all methods. The MIN-MAX method gives the best result for fringe orders greater than 0.6, a better result can be given by the rest methods for fringe orders less than 0.5. The three-wavelength criterion could yield better result than that of the two-wavelength for determination of the total fringe order. Owing to various noises, both criteria cannot assure to obtain correct fringe order. Therefore two-wavelength method would be sufficient to determine the total fringe orders with a correctly determined total fringe order.