We investigate recursive nearest neighbor search in a sparse domain at the scale of audio signals. Essentially, to approximate the cosine distance between the signals we make pairwise comparisons between the elements of localized sparse models built from large and redundant multiscale dictionaries of time-frequency atoms. Theoretically, error bounds on… (More)

Figure 1: Gray lines show decays of representation weight magnitudes as a function of approximation order k for several decompositions of unit-norm signals (4-second recordings of single piano notes described in Section 4.1). Thick black line shows a global compressibility bound with its parameters.