Malay Gupta

Objective and subjective speech quality evaluation of wideband noise reduction algorithms.

Subjective and/or objective measurements of speech quality are important in benchmarking speech enhancement algorithms. Subjective measures include ratings of speech quality by listeners, whereas objective measures compute a metric based on the clean and enhanced speech samples. While subjective quality ratings are the “gold‐standard,” they are also time‐ and resource‐consuming. An objective metric that correlates highly with subjective data is attractive, as it can act as a substitute for benchmarking and fine‐tuning the noise reduction algorithms. In this paper, the performance of several noise reduction algorithms for wideband (50–7000 Hz) telephony application was evaluated both subjectively and objectively. A custom wideband noise reduction database was created that contained speech samples corrupted by different background noises at different signal to noise ratios and processed by seven different noise reduction algorithms. Speech samples in the database were subsequently rated by a group of 32 lis...

A spatio-temporal power method for time-domain multi-channel speech enhancement

We present a new multi-stage iterative technique for enhancing noisy speech under low signal-to-interference-ratio (SNR) environments. In the present paper, the speech is enhanced in two stages, in the first stage the noise component of the observed signal is whitened, and in the second stage a spatio-temporal power method is used to extract the desired speech component. In both the stages, the coefficient adaptation is performed using the multi-channel spatio-temporal correlation sequences of the observed data. The technique is mathematically equivalent and is computationally simpler than the existing generalized eigenvalue decomposition (GEVD) or the generalized singular value decomposition (GSVD) based techniques. Simulation results under low SNR diffuse noise scenarios indicate significant gains in SNR without introducing musical noise artifacts.