On the Legibility of Segmented Numerals

Abstract

Research on the legibility of many new symbol configurations has not kept pace with their increasing use. Such novel configurations appear, for instance, in segmented numerals. This paper reports experiments on their discriminability. Perceptual confusions between members of pairs of seven-segment numerals decreased as these pairs differed in more line segments. Not all segments are equally important for perception. Their perceptive weight can be deduced from their respective contribution to the differences in shape and corresponds to the actually occurring confusions between numeral pairs. These results led to suggestions for improved numerals: a simplified configuration for 6 and 9, another choice of vertical segments for 1, and an accentuation of important segments by broadening or lengthening them somewhat. First, the improvements aim at increasing the discriminability of the numerals, second, at increasing their acceptability; i.e., resemblance to the traditional numeral shapes plays a role.