Speech in Noisy Environments: robust automatic segmentation, feature extraction, and hypothesis combination

The first evaluation for Speech in Noisy Environments (SPINE1) was conducted by the Naval Research Labs (NRL) in August, 2000. The purpose of the evaluation was to test existing core speech recognition technologies for speech in the presence of varying types and levels of noise. In this case the noises were taken from military settings. Among the strategies used by Carnegie Mellon University's successful systems designed for this task were session-adaptive segmentation, robust mel-scale filtering for the computation of cepstra, the use of parallel front-end features and noise-compensation algorithms, and parallel hypotheses combination through word-graphs. This paper describes the motivations behind the design decisions taken for these components, supported by observations and experiments.