Abstract

If the amplitude distribution immediately behind the Fourier transform plane is uniform, the amplitude distribution at the output plane will approximate a delta function. The inverse filters have this property but, unfortunately, they have operational difficulty involving gain and poles. Accordingly, Awwal et al.¹ proposed a novel amplitude modulated phase-only filter (AMPOF). The characteristics of the AM- POF are given by where s(fx,fy) is the Fourier transform of the input signal s(x,y), 0 < D ⩽ 1 is a constant and A is an adjustment factor which guarantees that (i) the indeterminate condition is avoided and (ii) the gain is less than unity. In this paper, a computer simulation program is used to identify the best values of D and A for the most efficient AMPOF. The results also show that the discrimination capability of the AMPOF based correlation system is considerably better than that of a phase-only filter.¹

© 1989 Optical Society of America