(under subclass 559) Subject matter wherein the optical Fourier transform spectrum is mathematically convolved (cross-correlated) with the spectrum of the spatial filter at the Fourier transform plane.
(1) Note. As opposed to the perfect match of the correlation function in matched filtering systems, the convolution function indicates a partial match between the optical Fourier transform spectrums of object and spatial filter.
(2) Note. A spatial filter is generally an emulsion mask having a transparent annular region in an otherwise opaque region used to eliminate undesired radiation that diverges from the optical axis beyond the confines of the transparent region.
(3) Note. The cross-correlation function is a measure of the similarity between two signals when one is delayed with respect to the other.
(4) Note. "Convolution" and "Cross-correlation" are interchangeable terms.
SEE OR SEARCH CLASS
365, Static Information Storage and Retrieval, 106, for radiant energy.
708, Electrical Computers: Arithmetic Processing and Calculating,
816, for optical correlation and convolution in electrical analog computers.
