Dynamical spectrogram, an aid for the deaf

Visual perception of speech through spectrogram reading has long been a subject of research, as an aid for the deaf or hearing im-paired. Attributing the lack of success in this type of visual aids mainly to the static form of information presented by the spectrograms, this paper proposes a system of dynamic visualisation for speech sounds. This system samples a high resolved, auditory-based spectrogram, with a window of 20 milliseconds duration, so that exploiting the periodicity of the input sound, it produces a phase-locked sequence of images. This sequence is then animated at a rate of 50 images per second to produce a movie-like image displaying both the time-varying and time-independent information of the underlying sound. Results of several preliminary experiments for evaluation of the potential usefulness of the system for the deaf, undertaken by normal-hearing subjects, support the quick learning and persistence of the gestures for small sets of single words and motivate further investigations.