Fundamentals of digital imagery and display

Images are two dimensional distributions of luminance L(x,y) wherein x and y are the spatial (distance) coordinates of the local luminance L. They can be represented by landscapes with plains for uniform gray patches, slopes and hills for luminance gradients, towers and pits for speckles and dots, walls and canals for lines and vectors, and so on. The spatial resolution required for faithful reproduction of the image is determined by very steep luminance gradients and small radii in curvature of contours, and by just noticeable differences (JND's) in low gradients. The required luminance resolution is determined by discernible luminance contrasts. The spatial resolution depends on the luminance contrast. In the luminance ranges of displays, one may assume that most operations are linear.