Realce de Cores Em Imagens de Sensoriamento Remoto Utilizando Rotacao de Matiz No Espaco IHS (Enhancement of Colors in Remote Sensing Images Using Rotation of the Matrix at the IHS (Intensity, Hue, and Saturation) Coordinates)

摘要

The multispectral color composite imagery, obtained by digital processing and displayed on video monitors through the combination of the fundamental colors red, green, and blue, consists in an efficient form of presentation. The visual or psychophysiologic perception of the brain to the stimulus of particular colors, tends to combine independently the quantitative components of the fundamental colors, the intensity (I), hue (H) and saturation (S), and so it is possible to perceive each one of these attributes of color, separately. A method is presented to increase the contrast of the colors, using a transformation to the IHS coordinates which permits individual manipulation in each of these components, in order to obtain a better control about the color composite generated in the video display. The basic procedure is a manipulation of the histograms of the components, I, H, and S, in order to increase, decrease, or offset the range of possible values of the components, by linear transformations. Test of this procedure using LANDSAT-TM scene of a region covered by geological research showed the different component manipulations resulted in different enhancements of lithologic units, formerly not distinguished in the original color composition, which allowed an easier photogeologic interpretation.