The subject of visual acquisition in its broadest sense involves many & diverse disciplines including surface properties, atmospheric physics , photometry, image evaluation, instrumental & visual optics, physiology, neuro-physiology and psychology. Inevitably, with a subject covering such broad interests, the data necessary for a total appreciation of the problems of practical visual acquisition tend to remain widely scattered. The book brings together the important data from each discipline in such a way as to provide a gradually unfolding story of the overall problem. Amongst other things, early chapters are devoted to surveys of the important properties of the eye, observer variability, the variation of threshold performance as a function of a wide range of parameters, modelling of visual performance and image evaluation techniques. Later chapters introduce the reader to the more complex factors affecting practical visual acquisition - local scene luminance structure, target structure & texture, atmospherics and surface reflectance properties - whilst the final chapter looks at field trials, field instrumentation and visual simulation. All facets of the subject are copiously referenced and a classified bibliography is provided for additional reading.