A method and apparatus are provided for identifying a noise environment
for a frame of an input signal based on at least one feature for that
frame. To identify the noise environment, a probability for a noise
environment is determined by applying the noisy input feature vector to a
distribution of noisy training feature vectors. In one embodiment, each
noisy training feature vector in the distribution is formed by modifying
a set of clean training feature vectors. In one embodiment, the
probabilities of the noise environments for past frames are included in
the identification of an environment for a current frame. In one
embodiment, a correction vector is then selected based on the identified
noise environment.