A modified spectrogram with possible application as a visual hearing aid for the deaf.

A modified spectrogram was developed, substantially improving visual word recognition over that of traditional spectrograms from 23% to 80%. Traditional spectrograms are difficult to interpret quickly due partly to poor contrast, subtle cues, and extraneous detail. Improvements developed here include increased frequency resolution, enhancement of inconspicuous but relevant information, and elimination of extraneous detail. Log-frequency and especially, sone-amplitude scaling were subjectively easier to interpret visually than linear-frequency, dB-amplitude, and linear-amplitude scaling. The spectrogram was made sufficiently small to fit into the center of vision, emulating written language in which individual words are recognized as discrete patterns.