A simple user interface system for recovering patterns repeating in time and frequency in mixtures of sounds

Repetition is a fundamental element in generating and perceiving structure in audio. Especially in music, structures tend to be composed of patterns that repeat through time (e.g., rhythmic elements in a musical accompaniment), and also frequency (e.g., different notes of the same instrument). The auditory system has the remarkable ability to parse such patterns by identifying repetitions within the audio mixture. On this basis, we propose a simple user interface system for recovering patterns repeating in time and frequency in mixtures of sounds. A user selects a region in the log-frequency spectrogram of an audio recording from which she/he wishes to recover a repeating pattern masked by an undesired element (e.g., a note masked by a cough). The selected region is then cross-correlated with the spectrogram to identify similar regions where the underlying pattern repeats. The identified regions are finally averaged over their repetitions and the repeating pattern is recovered.