Gerchberg-Saxton algorithm

In most acoustic microscopes the video signal is measured after detection by an envelope detector, so that the phase information has been lost. In order to attempt to reconstruct P(6)R(6) from a modulus only V(z) it is necessary to employ a phase retrieval algorithm (Fright et al. 1989). The method is based on the Gerchberg-Saxton algorithm (Gerchberg and Saxton 1972 Bates and McDonnell 1986). With the change of variables of (8.2) and with... 

Thus the data can be preprocessed by Fourier transforming V( ) 2, applying a window corresponding to the extent of the pupil function of the lens, and then inverse transforming to obtain a filtered V(m), which can then be used as the data for the Gerchberg-Saxton algorithm. 

Gerchberg, R. W. and Saxton, W. O. (1972). A practiced algorithm for the determination of phase from image and diffraction plane pictures. Optik 35, 237-46. [128]... 

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