Filtering high quality text for display on raster scan devices

Abstract

Recently several investigators have studied the problem of displaying text characters on grey level raster scan displays. Despite arguments suggesting that grey level displays are equivalent to very high resolution bitmaps, the performance of grey level displays has been disappointing. This paper will show that much of the problem can be traced to inappropriate antialiasing procedures. Instead of the classical (sin x)/x filter, the situation calls for a filter with characteristics matched hoth to the nature of display on CRTs and to the human visual system. We give examples to illustrate the problems of the existing methods and the advantages of the new methods. Although the techniques are described in terms of text, the results have application to the general antialiasing problem-at least in theory if not in practice.