As a result of solid state multispectral scanners and other raster input devices, we now have available digital raster images analysis techniques to the image data—a field of study called Digital Image Processing.

Digital Image Processing is largely concerned with four basic operations: image restoration, image enhancement, image classification, image transformation.

Image restoration is concerned with the correction and calibration of images in order to achieve as faithful a representation of the Earth’s surface as possible—a fundamental consideration for all applications.

Image enhancement is predominantly concerned with the modification of images to optimize their appearance to the visual system. Visual analysis is a key element, even in digital image processing, and the effects of these techniques can be dramatic.

Image classification refers to the computer-assisted interpretation of images—an operation that is vital to GIS.

Image transformation refers to the derivation of new imagery as a result of some mathematical treatment of the raw image bands.