Pattern playback from 1950 to 1995

This paper describes algorithms to convert spectrograms, cochleagrams and correlograms back into sounds. Each of these representations converts sound waves into pictures or movies. Techniques for inversion, known as the pattern playback problem, are important because they allow these representations to be used for analysis and transformations of sound. The algorithms described here use convex projections and intelligent phases guesses to iteratively find the closest waveform consistent with the known information. Reconstructions from the spectrogram and cochleagram are indistinguishable from the original sound. In informal listening tests, the correlogram reconstructions are nearly identical.