A simple parametric equation for pseudocoloring grey scale images keeping their original brightness progression

A new formalism to generate pseudocolor spectra is introduced. Therefore, a para-metric path in the RGB{color cube is derived to guarantee constant brightness progression. The resulting spiral{like curve allows the generation of various color spectra by adjusting the spiral's frequency and phase. The formalism allows the determination of the resulting number of colors in dependency of both parameters. Therefore, these spectra are particularly useful to represent 12 bit data on common computer graphic adapters with 4096 displayable pseudocolor values instead of 256 displayable grey intensities. In this paper, the spectra are applied to medical X{ray images yielding an enhanced visualization of the diagnostic information.