Digital Processing of Remotely Sensed Data

Publisher Summary This chapter describes some of the digital techniques that are often used in processing remotely sensed images and also discusses some of the sensors. These techniques include preprocessing techniques, enhancement techniques, geometric correction and registration techniques, and classification techniques. The earliest and the most useful form of remote sensing was photography. The photon energy that is radiated or reflected from objects is collected by a camera (sensor) and recorded on a light-sensitive film emulsion. Aerial multiband color photography can be used to identify various categories of objects on the ground. The technique of remote sensing to a great extent relies on the interaction of electromagnetic (EM) radiation with matter. Macroscopically, the interactions are absorption, transmission, reflection, and emission of radiation from the features. These are due to atomic and molecular absorption, as well as scattering. These physical processes affect the reflected/emitted radiation (signal) measured by the sensors. The remotely measured signal expressed as a function of wavelength is often referred to as the “spectral signature” of the target object on which the measurements have been made. The chapter highlights the applications of remote sensing. Remotely sensed spectral measurements can be a source of information for many applications. The applications of remote sensing include agriculture, forestry, geology, mineral resources, hydrology, water resources, geography, cartography, meteorology, and military.