The Aliasing Problem in Computer-Generated Shaded Images Certain defects, such as jagged edges and disappearing detail, have long been an annoyance in digitally generated shaded images. Although increasing the resolution or defocusing the display can attenuate them, an understanding of these defects leads to more effective methods. This paper explains the observed defects in terms of the aliasing phenomenon inherent in sampled signals and discusses prefiltering as a recognized cure. A method for evaluating filters is presented, the application of prefiltering to hidden-surface algorithms is discussed, and an implementation of a filtering tiler is shown accompanied by examples of its effectiveness. CACM November, 1977 Crow, F. C. aliasing, computer graphics, convolutional filtering, hidden-surface removal, sampling 8.2 CA771103 JB December 27, 1977 7:56 AM 2816 4 2913 2828 4 2913 2827 4 2913 2913 4 2913 3047 4 2913 2751 5 2913 2913 5 2913 2913 5 2913 2913 5 2913