A Comparison of Optical versus Hardware Fourier Transforms.

Abstract : A comparison of the optical transform versus the hardware Fourier transform was made for two input functions: a rectangular aperture and a six-pointed star design. The optical transforms were modified using sharp and smooth lowpass as well as highpass filters. The results were compared against those obtained using the array processor hardware at the Brooks Air Force Base, School of Aerospace Medicine. The ringing observed in the lowpass filtered results of the array processor was simulated by the optical methods. However, certain asymmetric in the hardware ringing data were not observed optically. A discussion of the ringing and how to eliminate it is also presented. (Author)