|RESPITE: The CASA Toolkit Page: Documentation: Block Library Index:GMask|
The GMask block produces `cleaned' speech, the present data mask and the probability of the present mask, using the noisy speech and the noise means and variance estimates. This block is intended to be used together with blocks such as the AdaptiveNoiseEstimation block which produce estimates of the noise mean and variance. It is assumed that the noisy data is spectral data, that the distribution of the estimated noise is Normal, and that the channels are independent.
The `cleaned' speech (out1) is simply the noisy speech minus the noise mean estimate. The probability of present data (out3) is P(estimated_SNR<NOISE_THRESHOLD), and the present data mask (out2) is computed as P(estimated_SNR<NOISE_THRESHOLD) > PROBABILITY_THRESHOLD.
WARNING: the cleaned speech may contain negative values!"
|Inputs||Meaning||Sample||1-D frame||2-D frame|
|in2||estimate of noise mean||Yes||Yes||Yes|
|in3||estimate of noise variance||Yes||Yes||Yes|
|out2||present data mask|
|out3||present data probability|
|NOISE_THRESHOLD||Float||6.952||Noise level threshold in dB (See above)|
|PROBABILITY_THRESHOLD||Float||0.600||Probability threshold for out2 (See above)|