Retrieval of symmetrical image blur using zero sheets

Abstract

The analytically continued Fourier transform of a two-dimensional image vanishes to zero on a two-dimensional surface embedded in a four-dimensional space. This surface uniquely characterises the image and is known as a 'zero sheet'. Since the manipulation of a function in four-dimensional space is cumbersome, the projections of zero sheets, known as 'zero tracks' are calculated. This knowledge of zero sheets can be extended to a number of practical applications including image processing. Image restoration can be realised without prior knowledge of the point spread function, i.e. blind deconvolution is possible even when only a single blurred image is given. If the blurred image concerned contains a point spread function with diagonal symmetry, the point zeros calculated row-wise and column-wise contain some similarities, which supports retrieval of both the true image and a point spread function. This novel scheme performs the separation effectively in the absence of contamination.