Rasta filtering

rdf:langString Rasta filtering

rdf:langString RASTA-filtering and Mean Subtraction was introduced to support (PLP) preprocessing. It uses bandpass filtering in the . Rasta filtering then removes slow channel variations. It has also been applied to cepstrum feature-based preprocessing with both log spectral and cepstral domain filtering. In general a RASTA filter is defined by The numerator is a with N being the order (must be odd) and the denominator is an integrator with time decay. The pole controls the lower limit of frequency and is normally around 0.9. RASTA-filtering can be changed to use mean subtraction, implementing a moving average filter. Filtering is normally performed in the cepstral domain. The mean becomes the long term cepstrum and is typically computed on the speech part for each separate utterance. A silence is necessary to detect each utterance.