A method and apparatus for determining masked thresholds for a perceptual auditory
model used, for example, in a perceptual audio coder, which makes use of a filter
bank structure comprising a plurality of filter bank stages which are connected
in series, wherein each filter bank stage comprises a plurality of low-pass filters
connected in series and a corresponding plurality of high-pass filters applied
to the outputs of each of the low-pass filters, and wherein downsampling is advantageously
applied between each successive pair of filter bank stages. In accordance with
one illustrative embodiment, the filter bank comprises low order IIR filters. The
cascade structure advantageously supports sampling rate reduction due to the continuously
decreasing cutoff frequency in the cascade. The filter bank coefficients may advantageously
be optimized for modeling of masked threshold patterns of narrow-band maskers,
and the generated thresholds may be advantageously applied in a perceptual audio coder.
