Recognition of local symmetries in gray value images by harmonicfunctions

摘要

A method for modeling symmetries of the neighborhoods ingray-value images is derived. It is based on the form of theiso-gray-value curves. For every neighborhood a complex number isobtained through a convolution of a complex-valued image with acomplex-valued filter. The magnitude of the complex number is the degreeof symmetry with respect to the a priori chosen harmonic function pair.The degree of symmetry has a clear definition which is based on theerror in the Fourier domain. The argument of the complex number is theangle representing the relative dominance of one of the pair of harmonicfunctions compared to the other