Digital Video and HD, 2nd Edition

1

Raster images

A digital image is represented by a rectangular array (matrix) of picture elements (pels, or pixels). Pixel arrays of several image standards are sketched in Figure 1.1. In a greyscale system each pixel comprises a single component whose value is related to what is loosely called brightness. In a colour system each pixel comprises several components – usually three – whose values are closely related to human colour perception.

Figure 1.1 Pixel arrays of several imaging standards are shown, with their counts of image columns and rows. The 640×480 square sampled structure common in computing is included; however, studio and consumer ...