An effective color scale for simultaneous color and gray-scale publications

Pseudocolored images are used in many signal processing applications to represent signal properties as a function of two independent variables, such as time and frequency. This paper describes a color scale that can be used to unambiguously represent these images in printed gray-scale publications as well as full color electronic publications. The image resolution when viewed in color is enhanced in this article. This color scale also allows for correct interpretation by people with common types of color blindness, which accounts for approximately 10% of the male population and 1% of the female population. While it may be possible to obtain a better resolution with a color scale that is designed for a particular image on hand, the proposed color scale works well in many applications where the user does not have the time or resources to tailor the color scale to a specific image. The proposed color scale is also easy to implement and has an intuitive interpretation in that it cycles through a sequence of hues that roughly resembles the familiar rainbow.