Extraction of reverberant sound using microphone arrays

Simple SummaryContent extracted from patent full text and abstract with AI.

This invention presents a method and apparatus for extracting reverberant (diffuse) sound from recordings made with two or more microphones. Unlike traditional approaches that focus on isolating direct sound from a source, this method estimates the spatial coherence (how similar or correlated the reverberant sound is between microphones) to define a new filter. This filter is specifically designed to pick up reverberant sound from all directions while suppressing direct sound and noise, by solving a constrained optimization problem. The technique can be implemented via software or hardware and is adaptable to various microphone arrays and environments.

Use CasesContent extracted from patent full text and abstract with AI.

• High-definition 3D audio or spatial sound reproduction systems for virtual reality (VR) or augmented reality (AR) environments, where authentic room acoustics are needed.
• Improved teleconferencing or remote collaboration where true room reverberation provides a sense of presence.
• Post-production tools for film, TV, and music to isolate and manipulate the reverberation of recorded environments independently from direct audio sources.
• Acoustic measurement and analysis tools for architectural acoustics or sound field research, allowing accurate retrieval of reverberant sound components.
• Hearing aids or assistive listening devices to distinguish between direct speech and environmental reverberation for enhanced listening comfort.
• Smart speakers or voice assistants, enabling robust sound scene analysis and environment-aware processing.

BenefitsContent extracted from patent full text and abstract with AI.

• Extracts reverberant sound accurately while minimizing inclusion of direct sound and noise, leading to higher fidelity in spatial audio reproduction.
• Does not require detailed information or estimation of the direction of every sound source, simplifying deployment in complex scenarios.
• Enables more realistic recreation of acoustic spaces for immersive audio experiences.
• Versatile: applicable to various array geometries and adaptable to diverse acoustic environments (e.g., different rooms or halls).
• Improved robustness to transient sounds and multiple sources compared to previous single-channel or conventional multi-channel methods.
• Can enhance machine listening applications, improving environmental awareness and user experience in intelligent audio devices.

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Patent Abstract

A method comprises estimating a spatial coherence between a first diffuse sound portion in a first microphone signal and a second diffuse sound portion in a second microphone signal. The first microphone signal is captured by a first microphone and the second microphone signal is captured by a second microphone which is spaced apart from the first microphone in a known manner. The method further comprises defining a linear constraint for filter coefficients of a diffuse sound filter, the linear constraint being based on the spatial coherence. The method also comprises calculating at least one of signal statistics and noise statistics over the first microphone signal and the second microphone signal. The method also comprises determining the filter coefficients of the diffuse sound filter by solving an optimization problem concerning at least one of the signal statistics and noise statistics while considering the linear constraint for the filter coefficients.