Acoustic Analysis for Automatic Speech Recognition

As a pattern recognition application, automatic speech recognition (ASR) requires the extraction of useful features from its input signal, speech. To help determine relevance, human speech production and acoustic aspects of speech perception are reviewed, to identify acoustic elements likely to be most important for ASR. Common methods of estimating useful aspects of speech spectral envelopes are reviewed, from the point of view of efficiency and reliability in mismatched conditions. Because many speech inputs for ASR have noise and channel degradations, ways to improve robustness in speech parameterization are analyzed. While the main focus in ASR is to obtain spectral envelope measures, human speech communication efficiently exploits the manipulation of one´s vocal-cord vibration rate [fundamental frequency (F0)], and so F0 extraction and its integration into ASR are also reviewed. For the acoustic analysis reviewed here for ASR, this work presents modern methods as well as future perspectives on important aspects of speech information processing.