Foreground Signal Suppression via Directional Diffuse Decomposition
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Solution Overview
Problem
Existing audio processing technologies fail to effectively suppress directional speech sources in crowded acoustic environments, such as sports events, to enhance the immersive experience by isolating ambient sound for broadcasting.
Innovation Solution
A processor-implemented method and system for foreground signal suppression using a compact circular sensor array, which decomposes sound fields into directional and diffuse components, applies beamformers to filter directional signals, and orthogonalizes microphone signals to produce a background channel, thereby isolating the ambient sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor arrays and spatial filtering are used to enhance individual sources, then individual source enhancement is improved, but ambient sound suppression deteriorates
Solution Approach 1:
The patent inverts the conventional approach by suppressing individual foreground sources (speech) to enhance the ambient background sound field. Instead of enhancing individual sources by suppressing ambient noise, the system suppresses directional speech sources to deliver immersive ambient sound to the listener, reversing the traditional signal enhancement paradigm
2Adaptability or versatility
If foreground sources are suppressed to enhance ambient sound, then immersive experience is improved, but speech intelligibility deteriorates
Solution Approach 1:
The patent segments the audio signal into directional (foreground speech) and diffuse (ambient background) components using diffuseness estimation and spatial filtering. This segmentation allows independent processing of speech and ambient sound, enabling the system to suppress speech while preserving ambient sound field characteristics for immersive broadcasting
3Object-generated harmful factors
If beamformers are applied to filter directional components, then directional signal suppression is improved, but phase and amplitude distortion of background signals worsens
Solution Approach 1:
The patent applies local quality by processing directional and diffuse components differently through separate signal paths. The beamformer selectively filters directional components while the diffuse component passes through with minimal processing, preserving the phase and amplitude characteristics of the ambient background sound while suppressing speech
Data Source
AI summary
A processor-implemented method for foreground signal suppression. The method includes: capturing a plurality of input signals using a plurality of sensors within a sound field; subjecting each input signal to a short-time Fourier transform to transform each signal into a plurality of non-overlapping subband regions; estimating the diffuseness of the sound field based on the plurality of input signals; decomposing each of the plurality of input signals into a diffuse component and a directional component based on the diffuseness estimate; applying a spatial analysis operation to filter the directional component of each of the plurality of input signals, wherein the spatial analysis operation includes applying a set of beamformers to the directional components to produce a plurality of beamformer signals; and processing the plurality of beamformer signals to decompose the signal into a foreground channel and a background channel.