SBIR Phase I: Enhanced Voice Capture for Mobile Devices Using a Mixed-Response-Type Array

The innovation is to develop very small audio subsystems for mobile audio devices with unprecedented noise and interference reduction. Audio subsystems are fundamental to many high-volume portable devices such as mobile phones, media tablets, and digital voice recorders. Multiple microphones can enhance audio capture and improve signal quality by reducing acoustic noise interference, but current arrays of separated omni-directional microphones require large spacing between microphones to achieve high discrimination. The small size of mobile communication devices thus fundamentally degrades the performance of existing array technologies. "Zero-aperture" mixed-response-type arrays that retain high directional selectivity with very closely spaced microphones coupled with innovative signal-processing methods may achieve unprecedented background noise and interference reduction with high target signal quality. The research will extend existing free-field arrays and adaptive beamforming methods to the different acoustics when embedded in handheld devices, will develop a novel real-time robust beamformer for small arrays, and will greatly increase noise and interference reduction through new multichannel noise-reduction processing. Successful research could fundamentally improve the signal capture and noise rejection of small mobile electronic voice communication devices, thus greatly improving their most fundamental function and enabling their effective use in a wider range of environments. The broader/commercial impact is to enhance and facilitate mobile voice communication for mobile device users. The voice and audio subsystem is a fundamental component of mobile devices including cell phones, smartphones and media tablets. Background noise interference during voice communication presents a major problem for many users, especially the millions of hearing impaired and elderly individuals who often struggle to communicate using current voice communications technology. Major device manufacturers have recently begun to implement microphone arrays in commercial devices, yet current voice capture systems fail to utilize the full potential of array technology for mobile applications. Market research has predicted that dedicated voice processor sales will grow to 1.6 billion units in 2015 from 63 million in 2010. Prior research has enabled the development of innovative mixed-response-type array technology, allowing arrays to be implemented effectively in smaller devices. However, a number of unsolved technical problems have prevented commercialization of the technology within the mobile market. This Phase I project will address these problems to deliver a disruptive voice processing solution, setting a new standard for voice capture performance in mobile devices.