Dot-Matrix Alphanumerics Viewed under Discrete Element Degradation

The legibility of five 5 × 7 dot-matrix alphanumeric fonts was evaluated under varying degrees of character degradation. After “importance values” had been experimentally determined for every spot of a 7 × 9 matrix, in the center of which lay a 5 × 7 stimulus alphanumeric, each character was exposed tachistoscopically while manipulating the removal or addition of high or low value dots. While differences were found among characters, no differences among fonts or between the manner of degradation were evidenced.