Both the logic underlying the recursive blur technique for optimising the legibility of symbol signs and the computer algorithms for implementing the technique are based upon 2-dimensional (2D) Fourier analysis. The use of 2D-Fourier analysis for the description of complex spatial structures (such as highway signs) is introduced in this paper. This framework is extended to show how 2D-Fourier techniques can be used to "filter-out" specific structural components from a sign stimulus and how this filtering approach has been employed to engineer highway signs with improved legibility.
Abstract