Abstract

In the visible spectrum, color is the physiological interpretation of wavelength, and has both conscious and unconscious emotive connotations that affect perception. Black-and-white images contain only intensity data, but color images include spectral information which greatly increases our ability to distinguish various materials. Single band mid-infrared (typically 8–12-μm) images are difficult to interpret because they contain only intensity information, despite the strongly structured spectral character of many emissions of this fingerprint region, particularly for gases and vapors. False color techniques denoting intensity levels are inherently misleading to human intuition. To test human interpretation of the spectral content of a detailed thermal image, experiments were conducted to produce and evaluate true-color infrared images containing both intensity and spectral data. Imagery was collected in three selected spectral bands per scene with a mid-infrared thermal camera. These scenes were weighted and combined by an image processor to permit the display of the infrared data as the three standard visible colors (RGB) on a video monitor. The images of the various scenes observed with this apparatus are compared with visible and conventional infrared scene images to evaluate the usefulness of the technique. Recommendations as to the incorporation of the technique in a single three-band thermal camera are provided.

© 1986 Optical Society of America