The Design of an Optimum Alphanumeric Symbol Set for Cockpit Displays.

摘要

The purpose of this study was to design an alphanumeric symbol set with improved legibility which could be implemented as a standardized set for cockpit displays. Pattern recognition theory was applied in which the two-dimensional, discrete, Fourier transform was used to obtain the feature space for each symbol. Spatial lowpass filtering techniques were employed and a decision rule was used based on the maximum nearest prototype Euclidian distance between symbols. A symbol change algorithm was developed in which symbols were moved away from their two closest neighbors in the transformed domain. Lincoln/Mitre, a highly legible font, was used as the initial prototype set. A new alphanumeric symbol set was designed with 18 changed symbols that had an overall greater distance spread between nearest neighbor symbols. The Lincoln/Mitre and a new test set were psychophysically tested with results indicating a 9.5% better performance for the changed symbols over the original Lincoln/Mitre symbols. (Author)