The current state-of-the-art automatic speech recognition (ASR) technology completely fail when confronted with wide variety of distortions occurring in less then completely controlled (close talking - noise cancelling microphone, no noise) environment. The "missing data" approach to robust ASR accepts the fact that some spectro-temporal regions will be dominated by noise, and therefore lost for subsequent processing. The problem of ASR then decomposes into two subproblems:
We are investigating various techniques that address the second subproblem in the context of an standard HMM based ASR system.