| 摘要 |
<p>A digital filter design apparatus for noise suppression by spectral subtraction includes a first spectrum estimator (12) for determining a high frequency-resolution noisy speech power spectral density estimate from a noisy speech signal block. A second spectrum estimator (24) determines a high frequency-resolution background noise power spectral density estimate from a background noise signal block. Averaging units (20, 26) form a piece-wise constant noisy speech power spectral density estimate and a piece-wise constant background noise power spectral density estimate. These averaging units are controlled by means (14, 16, 18) for adapting the length of individual segments to the shape of the high frequency-resolution noisy speech power spectral density estimate and for using the same segmentation in both piece-wise constant estimates. Means (28) determine a piece-wise constant digital filter transfer function using spectral subtraction based on the piece-wise constant noisy speech power spectral density estimate and the piece-wise constant background noise power spectral density estimate.</p> |
