From X-rays to radar: using color to understand imagery

This paper discusses the problems of collecting and processing imagery across the electromagnetic spectrum from X-rays to radar. The authors in this overview paper start at the short wave length part of the spectrum and go through the spectrum (X-rays) to the longer wavelength and synthetic aperture radar (SAR) imagery and describe the problems of collecting imagery and understanding this imagery. The sub bands of the spectrum that are discussed include X-rays, ultraviolet, visible images from violet to red, the infrared bands including short wave, mid wave, and long wave, the millimeter wave, and the meter wavelength or SAR images. The use of color or using multiple sub bands at each part of the spectrum to improve image understanding are described. The advantages of using color and the problems of collecting color imagery in each part of the spectrum are discussed in this paper. Examples are given of the sensors, the images, and the color image processing required to understand these images. Other factors such as special resolution obtainable in each sub band, amount of human intervention required to understand the imagery, and number of bands to collect and process versus improvement in understanding of the images are also be described.