Second generation and perceptual wavelet based noise estimation

The implementation of three noise estimation algorithms using two different signal decomposition methods: a second-generation wavelet transform and a perceptual wavelet packet transform are described in this paper. The algorithms, which do not require the use of a speech activity detector or signal statistics learning histograms, are: a smoothing-based adaptive technique, a minimum variance tracking-based technique and a quantile-based technique. The paper also proposes a new, robust noise estimation technique, which combines a quantile-based algorithm with smoothing-based algorithm. The performance of the latter technique is then evaluated and compared to those of the above three noise estimation methods under various noise conditions. Reported results demonstrate that all four algorithms are capable of tracking both stationary and non-stationary noise adequately but with varying degree of accuracy