Abstract: Computer-synthesized images exhibit the typical artifacts of raster displays, called aliasing, rastering, staircasing or the "jaggies." Display of an image on a raster CRT requires the sampling the two dimensional image signal I( x, y) to obtain a pixel-based description of intensity. Unfortinately, this sampling process treates the pixel as a mathematical point and the point sampling of an unfiltered object is never correct at any resolution. Aliasing effects (spatial and temporal) are due to undersampling of the image signal. Spatial aliasing occurs when images contain frequencies greater than one half the spatial sampling frequency. Lines that should be straight appear jagged, very small objects may not be visible, portions of long thin objects may disappear.