Abstract: Image generation for raster displays proceeds in two main steps: geometry processing and pixel processing. The snbsystem performing the pixel processing is called display processor.In the paper a model for the displa.y processor is developed that takes into account both function and timing properties. The model identifies scan conversion, hidden surface removal, shading and anti-aliasing as tile key functions of the display processor. The timing model is expressed in an inequation being fundamental for all display processor architectures.On the basis of that model a taxonomy is presented which classifies display processors according to four main criteria: function, partitioning, a.rchitecture and performance.The taxonomy is applied to five real display processors: Pixel-planes, SLAM, PROOF, the Ray-Casting Machine and the Structured Frame Store System.Investigation of existing display processor architectures on the basis of the devel oped taxonomy revealed a potential new architecture. This architecture partitions the image generation process in image space and employs a tree topology.