A wave-confining metasphere beamforming acoustic sensor for superior human-machine voice interaction

Abstract

Highly sensitive, source-tracking acoustic sensing is essential for effective and natural human-machine interaction based on voice. It is a known challenge to omnidirectionally track sound sources under a hypersensitive rate with low noise interference using a compact sensor. Here, we present a unibody acoustic metamaterial spherical shell with equidistant defected piezoelectric cavities, referred to as the metasphere beamforming acoustic sensor (MBAS). It demonstrates a wave-confining capability and low self-noise, simultaneously achieving an outstanding intrinsic signal-to-noise ratio (72 dB) and an ultrahigh sensitivity (137 mV pp /Pa or −26.3 dBV), with a range spanning the daily phonetic frequencies (0 to 1500 Hz) and omnidirectional beamforming for the perception and spatial filtering of sound sources. Moreover, the MBAS-based auditory system is shown for high-performance audio cloning, source localization, and speech recognition in a noisy environment without any signal enhancement, revealing its promising applications in various voice interaction systems.

An ultrahigh sensitivity acoustic sensor system for weak signal detection based on an ultrahigh-Q CaF2 resonator

“…High-quality speech signal acquisition and reconstruction [25][26][27][28] , especially for accurate speech recognition in noisy backgrounds, requires acoustic sensors combined with ultrahigh sensitivity, broadband response, and low noise. In particular, acoustic sensors have a high response in the low-sound band, so there is an urgent need to develop acoustic sensing technology with ultrahigh sensitivity over a wide frequency range.…”

Rayleigh angle incident ultrasonic beam shape design influence on reflected beam

“…A cross-fertilization between optics and acoustics in more recent times is found in the similarity between photonic crystals and phononic crystals or metamaterials in general. Recent advances in metamaterials [28][29][30][31][32][33][34][35][36][37][38] offer novel possibilities in transducer design, beam forming, and beam focusing. Provided with a new range of design possibilities, potential interest transpires in ultrasonic nondestructive testing and the occurrence of a guided waverelated beam effect, such as the Schoch effect, under unorthodox shapes of incident beams.…”

Soft Sensors and Actuators for Wearable Human–Machine Interfaces

“…32 However, significant efforts are still underway to develop acoustic sensors with improved sensitivity and signal-to-noise (SNR) in order to accurately discern desired sound waves across the wide frequency range of human hearing (0.02−20 kHz). Moreover, to mitigate the impact of environmental noise, additional research is focused on developing acoustic sensors with omnidirectional perception, spatial filtering of sound sources, 33 and selective frequency sensing capabilities. 3 Tactile signals play a crucial role in various HMI technologies.…”