Monochromatic representation of color images

Abstract

A color to monochromatic image transformation which transforms each color area of the original image into a corresponding area of a monochromatic image having a particular pattern of `light` and `dark` dots corresponding to and representing the original color of the area. The dot patterns are selected to provide both gray scale representations of the original colors and differing textural appearances for each color, so as to maximize the discrimination between the areas of the monochromatic image. The monochromatic dot patterns do not necessarily correspond exactly to the colors or gray scale values of the original colors, but are selected to provide visual impressions analogous to the visual impressions provided by the corresponding original colors. A further feature of the dot arrays selected to represent various colors is that the patterns of dots are selected for each array so as to avoid the creation of artifacts, that is, the formation of accidental or incidental patterns and figures within a given array or at the junction or border between two arrays. A yet further feature is the enhancement, during transformation, of the visual appearance of alphanumeric characters and symbols. The original background color of the character or symbol is transformed into a monochromatic color pattern mask dot pattern as previously described. The original character or symbol foreground color field, that is, the character or symbol itself, however, is either transformed into a dark (black) field if the background color was `light` or into a light (white) field if the background color was `dark`. In the latter case, the original foreground field is effectively discarded and the character or symbol appears as a light `hole` in the `dark` background field.