A New Approach to Model Pitch Perception Using Sparse Coding
Fig 13
Iterated rippled noise for different time delays and repetitions.
The figures show the results of 500 simulations for each case of IRN stimulus. Each subplot along the columns show the delays of d = 5, 4, and 2 ms that correspond to the fundamental frequencies of 200, 250, and 500 Hz, respectively. The subplots in the first row show the delay-add simulations, and the lower row shows the delay-subtract simulations. The results are derived from the first peaks of the resulting pdfs, and all estimations are taken from an interval of one octave around the appropriate fundamental frequency [42]. Simulations are done using Carney's model (Zilany et al. [27–29]) with stimuli of 70 dB SPL. The dictionary contained 1000 groups of sine-atoms with distinct CFs and 10 phases in each group (g = 10, Eq 3).The blue dots indicate rippled noise (one repetition), red points correspond to IRN with 2 repetitions, and yellow dots are for the 10 repetitions. (A-C) The delay-add simulations show distinct peaks around the 1/d frequencies. (D-F) The delay-subtract simulations show accumulation of the inferred pitches at frequencies equal to or greater than 1/d±10%, but the results for this case are noisy and inaccurate relative to psychoacoustic measurements.