A modern treatment of both direct and inverse problems applicable to the remote sensing of earth from space or from the air. Starting from a physical description of the process, the authors develop innovative mathematical models, fundamental mathematics for the analysis of these models, and methods for obtaining computational solutions. They also include the results of recent research using this approach, such as invariant imbedding techniques, associative memory artificial neural networks, and the automatic evaluation of derivatives. With its coverage of uniform parallel illumination, internal sources, and incident spotlight beams, this book is indispensable for researchers working to reduce the atmospheric distortion of remotely sensed terrestrial images.