Dual-Microphone Array Spatial Interference Suppression
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Solution Overview
Problem
Conventional personal and mobile voice communication systems face challenges with omnidirectional microphones picking up unwanted environmental noise, leading to impaired voice quality due to high computational complexity and sensitivity to mechanical vibrations, especially in systems like laptops where directional microphones are difficult to integrate.
Innovation Solution
A dual-microphone array system with a predefined distance between microphones is used to calculate phase differences and angular distances, allowing for the calculation of directional-filter coefficients to filter out undesired signals, employing a simplified signal model and low-complexity algorithm for efficient interference suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If omnidirectional microphones are used to capture voice signals, then the microphone can receive sounds from all directions, but environmental noise and interference are also picked up, degrading voice quality
Solution Approach 1:
The omnidirectional sound field is segmented into directional components by using multiple microphones arranged in an array. Each microphone captures sound from its specific location, and the combined signals are processed to separate desired voice directions from unwanted environmental noise directions, enabling selective audio capture.
Solution Approach 2:
Signal processing algorithms act as intermediaries between the microphone array and the output signal. These algorithms process the raw signals from multiple microphones, calculating phase differences and angular distances to identify and suppress spatial interference while preserving desired voice signals.
2Object-affected harmful factors
If traditional beamforming techniques are used to suppress interference, then spatial filtering is achieved, but computational complexity increases
Solution Approach 1:
The patent changes the parameters of the signal processing approach by using simplified phase difference calculations and angular distance computations based on predefined microphone positions. This transforms complex beamforming operations into more efficient parameter-based filtering, reducing computational burden while maintaining interference suppression effectiveness.
3Object-affected harmful factors
If directional microphones are integrated into devices like laptops, then spatial selectivity is improved, but manufacturing and integration difficulty increases
Solution Approach 1:
The patent makes the microphone array system universal by using standard omnidirectional microphones that can be easily integrated into existing devices, rather than requiring specialized directional microphones. The spatial directionality is achieved through the arrangement and signal processing of multiple identical microphones, simplifying manufacturing and integration.
4Object-affected harmful factors
If complex signal processing is applied to suppress interference, then voice quality improves, but processing time and energy consumption increase
Solution Approach 1:
The patent applies partial action by processing only the essential features of the audio signal - specifically phase differences and angular distances - rather than performing complete spectral analysis or complex beamforming. This selective processing achieves sufficient interference suppression with reduced computational time and energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses spatial interference, improving voice quality and reducing computational complexity, while being robust against microphone sensitivity mismatches and avoiding self-noise amplification, with better performance compared to traditional beamforming techniques.
Implementation Method 1
A phase difference between the first and the second microphone signals can be calculated based on the predefined distance. Angular distances between directions of arrivals (DOAs) of the source signals and the desired capture direction can be calculated based on the phase difference.
Data Source
AI summary
Systems, processes, devices, apparatuses, algorithms and computer readable medium for suppressing spatial interference using a dual microphone array for receiving, from a first microphone and a second microphone that are separated by a predefined distance, and that are configured to receive source signals, respective first and second microphone signals based on received source signals. A phase difference between the first and the second microphone signals is calculated based on the predefined distance. An angular distance between directions of arrival of the source signals and a desired capture direction is calculated based on the phase difference. Directional-filter coefficients are calculated based on the angular distance. Undesired source signals are filtered from an output based on the directional-filter coefficients.