title: pi-Phase filtering of the zero-frequency spectral component and pseudocolor encoding.
abstract: The basic problem of obtaining contrast reversal by pi-phase filtering of an image is discussed, and the condition for obtaining contrast reversal is deduced. Computer-simulation results are presented. These-show that, in general, within a certain density range pi-phase filtering produces contrast reversal, that this reversal is strongly dependent on the width of the filter, and that this filtering will cause deformation of density in pseudocolor encoding. The effect of the width of the filter and the density distribution of the image on encoding deformation and the density range of contrast reversal is demonstrated.
authors.forename: W
authors.initials: W
authors.lastname: Zhiheng
authors.forename: G
authors.initials: G
authors.lastname: Lurong