Sound Pickup Apparatus Using Triangular Microphone Array for Directional Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sound source separating technologies face challenges in forming sharp directionality only in a target direction while maintaining sound quality and suppressing reverberation effects, especially in environments with strong reverberation and multiple sound sources.
Innovation Solution
A sound source separating apparatus using a combination of bidirectionality and unidirectionality forming units with three microphones arranged in an isosceles or regular triangle configuration, employing spectral subtraction to extract target sounds while canceling overlapping directionality areas and correcting power imbalances between microphone arrays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a unidirectional filter is used to form directionality in the target direction, then directionality is formed, but the directionality in the target direction becomes weak
Solution Approach 1:
The patent combines bidirectionality forming and unidirectionality forming units to create a composite directional filter. The bidirectionality unit provides strong directionality in the target direction, while the unidirectionality unit suppresses sounds from the opposite direction. By merging these two functional units, the system achieves both strong directionality and sound quality preservation that neither unit could achieve alone.
2Measurement precision
If spectral subtraction is used to form strong directionality in the target direction, then directionality is strengthened, but directionality is also formed in the direction opposite to the target direction
Solution Approach 1:
The patent applies different directional characteristics to different spatial regions. The bidirectionality forming unit creates strong directionality in the target direction while the unidirectionality forming unit creates a dead angle in the opposite direction. This local differentiation of directional properties allows the system to strengthen directionality where needed while suppressing reverberation from specific directions.
3Measurement precision
If multiple microphone arrays are used to form directionality in various directions, then strong directionality can be formed, but device complexity increases
Solution Approach 1:
The patent segments the directional filtering function into two independent functional units: bidirectionality forming and unidirectionality forming. Each unit processes signals from the same three-microphone array but applies different directional characteristics. This segmentation allows the system to achieve complex directional control without adding more physical microphones, thereby reducing device complexity while maintaining directionality strength.
Data Source
AI summary
A sound pickup apparatus and method form a bidirectionality and a unidirectionality based on sound signals picked up by microphones arranged at vertices of a triangle. A target sound is extracted by performing a spectral subtraction operation and, with respect to each frequency, a ratio of amplitude spectra of beamformer outputs between outputs is calculated for each microphone array of a directionality forming unit. A mode or median of the calculated ratio of amplitude spectra is set as a correction coefficient which corrects power of beamformer outputs for each of the microphone arrays and a target area sound is extracted.