Exploring Antenna Placement Configurations with a Radar-based Silent Speech Interface

Silent Speech Interfaces (SSIs) are systems developed to reconstruct speech based on non-acoustic bio-signals generated by brain, muscular or articulatory activity. A broad variety of sensing methods have been employed in SSIs, but determining a single optimal sensor configuration is generally a challenge. This work focuses on investigating sensing configurations for an on-body radar-based SSI and evaluating them based on their phoneme recognition performance. Audio and radar data were recorded synchronously by 8 native German speakers. One emitting and two receiving antennas were placed on the cheeks of each speaker in three different configurations, which were evaluated by nested cross-validated Support Vector Machines (SVMs). With these sensing configurations, higher accuracies than in previous works with on-body radar-based SSIs were achieved for individual speakers and for a multi-speaker evaluation. This work succeeds to produce an antenna placement guideline for future recordings with similar SSIs.