This report will present a procedure for assessing the degree of visual detail which a user can perceive in an arbitrary computer-generated image. This will involve describing an image in terms of its component spatial frequencies (c/deg); a measure which is commonly employed in the field of visual perception to characterise the efficacy of the human visual system. The text will present a brief introduction to this visual metric, and then demonstrate how a full-colour computer-generated image can be described in terms of this metric. The approach advocated here is based upon an image segmentation algorithm: Fourier techniques will be considered, and shown to be inappropriate for this particular application. Keywords: Computer graphics, visual perception, visual acuity, spatial frequency. 1 Introduction For decades, the field of computer graphics has striven to produce ever-more visually realistic displays. This has seen a progression from simple, bland wireframe figures to fullcolour..