Color raster graphics is being incorporated into CAD systems for printed circuit board (PCB) design. An interactive prototype CAD system developed as an experimental base is described, along with color graphics research using this prototype. Areas investigated included the generation and display of complex PCB's, the display of depth information using “2 1/2 dimensional” techniques, performance measurements on color raster systems, possibilities for new on-line design audit techniques, color graphics primitives, hardware and software architectures, and human factors considerations.

A projection of a digital picture (image) may be defined as an ordered set of values, each of which is the sum of the gray levels along a given path drawn through the picture. A projection set is at ordered set of projections of the picture. Given a projection set, reconstruction is achieved by operating on the projection set to produce either the original picture or an approximation to it.