The physiological microphone (PMIC): A competitive alternative for speaker assessment in stress detection and speaker verification

Interactive speech system scenarios exist which require the user to perform tasks which exert limitations on speech production, thereby causing speaker variability and reduced speech performance. In noisy stressful scenarios, even if noise could be completely eliminated, the production variability brought on by stress, including Lombard effect, has a more pronounced impact on speech system performance. Thus, in this study we focus on the use of a silent speech interface (PMIC), with a corresponding experimental assessment to illustrate its utility in the tasks of stress detection and speaker verification. This study focuses on the suitability of PMIC versus close-talk microphone (CTM), and reports that the PMIC achieves as good performance as CTM or better for a number of test conditions. PMIC reflects both stress-related information and speaker-dependent information to a far greater extent than the CTM. For stress detection performance (which is reported in % accuracy), PMIC performs at least on par or about 2% better than the CTM-based system. For a speaker verification application, the PMIC outperforms CTM for all matched stress conditions. The performance reported in terms of %EER is 0.91% (as compared to 1.69%), 0.45% (as compared to 1.49%), and 1.42% (as compared to 1.80%) for PMIC. This indicates that PMIC reflects speaker-dependent information. Also, another advantage of the PMIC is its ability to record the user physiology traits/state. Our experiments illustrate that PMIC can be an attractive alternative for stress detection as well as speaker verification tasks along with an advantage of its ability to record physiological information, in situations where the use of CTM may hinder operations (deep sea divers, fire-fighters in rescue operations, etc.). (C) 2009 Elsevier B.V. All rights reserved.