Interpretation of imagery requires contrast between the object being sought and its background. A technique is described for increasing the contrast of selected objects based on their spectral reflectance or emittance characteristics, and two applications are discussed. Means for implementing this technique with an optical-mechanical scanner, multielement dispersing spectrometer, and electronic signal processing equipment are discussed.
Donald S. Lowe and John G. N. Braithwaite, "A Spectrum Matching Technique for Enhancing Image Contrast," Appl. Opt. 5, 893-898 (1966)