Double entendre: Embedding a secondary message in pointillistic speech
Gerald D. Kidd, Christine R. Mason · The Journal of the Acoustical Society of America · 2015
A dual-purpose application for pointillistic speech (Kidd et al., JASA 126, EL186–201) will be described. The speech was represented by a time-frequency matrix of pure-tone “points” derived from the original stimulus. The pattern of frequencies and intensities of the points coded the primary message while the phases of the points coded an independent secondary message. For example, the audible and intelligible word “shoes” may also convey the (inaudible, unintelligible) ASCII characters of the phrase “The road goes ever on and on…” by the binary phase-coded bit pattern of the pointillistic representation of “shoes.” The success in recovering the secondary message via signal processing was examined while the intelligibility of the primary message in speech recognition experiments was measured. Tradeoffs for accuracy in primary and secondary message transfer/reception were explored for both pointillistic speech and hybrid speech comprising natural and pointillistic representations. Some initial observations about the possible uses and limitations of this approach will be considered. [Supported by AFOSR award FA9550-12-1-0171.]