Electronic focus correction by signal convolution

Abstract

An electronic focus correction system is provided. The invention (10) is adapted to correct focus aberrations in an electronic imaging system which provides electrical signals representative of a scene of image data. The invention includes a memory (12) for providing sets of weighting coefficients and a two dimensional convolver (18) for multiplying the input electrical signals corresponding to a window in and around each pixel of image data by a set of the weighting coefficients. The two dimensional convolved (18) assigns to each pixel a value equal to the sum of the products of the coefficients times the electrical signals within each window to provide a plurality of weighted output signals. The output signals constitute a corrected image. A controller (20), responsive to the output of the two dimensional convolver (18), is provided to measure the figure of merit for the corrected image. Coefficient control logic (108) responsive to the output of the controller (20) is included for providing signals to select an alternate set of coefficients for multiplication with the input signals to thereby provide a corrected image with an optimized figure of merit. In a more specific embodiment, model adjustment logic (112) is included for changing the power spectral density of the corrected image.