Beamforming Steering via Weighted Virtual Microphones
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Solution Overview
Problem
Existing beamforming techniques using Differential Microphone Arrays (DMAs) are limited in their ability to perform continuous steering of Virtual Microphone polar patterns in arbitrary directions, restricting their application in sound source localization.
Innovation Solution
The method involves combining microphone signals to create directional Virtual Microphones with weighted radiation patterns, allowing for continuous steering within circular sectors defined by pairs of Virtual Microphones, enabling the main-lobe of the sum radiation pattern to be oriented towards a desired direction by adjusting weights based on pattern direction angles and separation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Differential Microphone Array techniques are used to create Virtual Microphones, then directional radiation patterns can be obtained, but continuous steering in arbitrary directions is limited
Solution Approach 1:
The patent segments the circular sector into multiple angular intervals and creates separate Virtual Microphones for each interval. Each Virtual Microphone is responsible for a specific angular range, allowing the system to achieve continuous steering coverage by switching between different Virtual Microphones based on the desired direction.
Solution Approach 2:
The patent introduces adjustable weighting coefficients that dynamically combine signals from multiple Virtual Microphones. By varying these weights based on the desired steering direction, the system can continuously steer the main-lobe of the sum radiation pattern to any direction within the circular sector, transitioning smoothly between different directional patterns.
2Measurement precision
If Virtual Microphones are combined to form sum radiation patterns, then beamforming can be achieved, but the main-lobe direction is constrained to specific angles
Solution Approach 1:
The patent changes the parameters of the radiation patterns by introducing adjustable weighting coefficients that depend on the desired main-lobe direction. By modifying these weights based on the target angle, the system can steer the main-lobe to any direction within the circular sector while maintaining the desired radiation pattern shape and localization accuracy.
3Measurement precision
If directive Virtual Microphones are created with specific polar patterns, then sound source localization is improved, but the system cannot adapt to arbitrary steering directions
Solution Approach 1:
The patent creates a universal beamforming system where Virtual Microphones with specific polar patterns can be adaptively combined to achieve steering in any direction within the circular sector. The weighting mechanism allows the same set of Virtual Microphones to serve multiple functions - maintaining their directional characteristics while enabling flexible steering through weighted summation.
Data Source
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AI summary
Beamforming method employing a microphones array to obtain Virtual Microphones having respective signals determining respective patterns of radiation, rotated at different pattern direction angles and with a separation angle, so that at least a circular sector is defined between said different pattern direction angles said separation angle between the at least a pair of Virtual Microphones being lower than n/2, obtaining a sum radiation signal with a sum radiation pattern associating a respective weight to the signals of said pair of directional Virtual Microphones, obtaining weighted signals of radiation and summing said weighted signals computing said respective weights as a function of a determined pattern direction angle of the pattern of radiation of said pair of directional Virtual Microphones and of the separation angle so that a main-lobe of said sum radiation pattern is steered within said circular sector to point in the direction of said determined pattern direction angle.