Configurable Microphone Array for Interference Direction Exclusion
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Solution Overview
Problem
Microphone arrays with automatic beam focusing often focus on unwanted acoustic interference sources, such as projectors, speakers, and air conditioners, degrading speech signal quality, especially when these sources have varying spatial positions relative to the array or become apparent during a call.
Innovation Solution
The microphone array detects a predefined control sound signal from the direction of an interfering source and configures itself accordingly, using a configurable directivity unit to exclude or modify signal processing based on detected control signals, allowing flexible and user-friendly configuration without requiring precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic beam focusing is used to detect the direction of maximum sound energy, then the microphone array can automatically track speakers, but it may focus on interfering sound sources instead of speakers
Solution Approach 1:
The system performs preliminary scanning of the search area to identify potential sound sources before committing to automatic beam focusing. By pre-processing the acoustic environment and marking interference sources, the system prepares configuration data that prevents the beam from focusing on unwanted sources in the first place
Solution Approach 2:
The system continuously monitors sound sources and compares detected interference patterns against stored configuration data. When a sound source matches a marked interference pattern, the system provides feedback to adjust the beamforming weights and exclude that direction from focusing, creating a closed-loop control system that prevents false focusing
2Adaptability or versatility
If the microphone array scans all directions in the search area, then it can detect speakers from any position, but it increases the likelihood of detecting interfering sound sources
Solution Approach 1:
The system applies different processing qualities to different regions of the search area. Directions marked as containing interference sources receive specialized processing (exclusion or attenuation), while other directions maintain normal scanning and detection capabilities. This localized differentiation allows comprehensive coverage while protecting against interference
3Manufacturing precision
If the microphone array configures itself to focus on detected sound sources, then it improves speech signal quality, but it may amplify interfering sound sources
Solution Approach 1:
The system takes preliminary anti-action by pre-identifying and marking interference sources in the configuration data before automatic beam focusing begins. When scanning detects a sound source, the system checks against this pre-prepared configuration and prevents focusing on marked directions, thereby preventing interference amplification before it can occur
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 solution effectively reduces error rates and improves audio quality by allowing intuitive and rapid adaptation to interference sources, eliminating regions of the search area and enhancing signal processing flexibility.
Implementation Method 1
The arrangement 200 of a plurality of microphone capsules 210... The output signals 315 of an arrangement of microphone capsules 310
Implementation Method 2
the beamforming unit 320 with configurable directivity... combine their output signals to achieve a specific directionality of the array
Implementation Method 3
The direction of a sound source can be detected by analyzing the delays between the sound signals arriving at the microphone capsules
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
Microphone arrays with an automatic beam focusing function can detect sound sources within a search region in an autonomous manner, capture the sound of the sound sources, and output same, for example for conference telephones. Said microphone arrays can easily focus on disruptive sound sources and capture disruptive noises. In order to prevent this from happening, a user plays back a defined control audio signal from the direction (137) of a disruptive sound source (130) via a portable electronic device (110), such as a smartphone with a special app. The microphone array (100) detects the defined control audio signal and the direction (137) of the reception of said audio signal and in response thereto configures itself automatically in accordance with the control audio signal and the reception direction. For example, the reception direction can be damped or eliminated from the search region of the microphone array, or a previously configured damping or elimination of a direction can be canceled. Advantageously, the configuration is simple to carry out and does not require a defined orientation of the microphone array in the room. The elimination of parts of the search region can reduce error rates and improve the audio quality.