Fig. 3.

De-fringing by super-Gaussian functions. To carry out the de-fringing, super-Gaussian functions with various power values, shown in Fig. 3a, have been used to multiply the amplitudes of the original image, which is represented by the thick line in Fig. 3b. The resulting amplitude profiles are shown in (b), with thin, dashed and dotted lines representing the super-Gaussian of powers of 6, 8, and 10, respectively. The super-Gaussian filter with a power of 8 gave the smoothest amplitude profile.