Directional Audio Capturing via Beamforming Weight Selection
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Solution Overview
Problem
Existing audio capturing systems for video production, such as those used in sports events, face challenges in selectively capturing sound under noisy conditions and fail to provide controlled steer and zoom functionality effectively, especially when multiple sound sources are present.
Innovation Solution
A system comprising one or more broadband microphone arrays, A/D signal converting units, and a control unit with input and signal processing means that receives position data to selectively focus and steer sound, using spectral analysis and spatial filtering techniques to generate a directional audio output, allowing for real-time or post-processing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a microphone array is used to capture sound from multiple sources, then the ability to capture sound from different locations is improved, but the difficulty of selectively isolating specific sound sources in noisy conditions increases
Solution Approach 1:
The system divides the audio capture task into multiple independent microphone channels, each capturing sound from a specific spatial direction. By segmenting the microphone array into multiple directional channels and processing them separately through beamforming, the system can isolate specific sound sources in noisy environments while maintaining the ability to capture from different locations.
Solution Approach 2:
The patent applies different signal processing characteristics to different spatial regions. By configuring microphones with specific directional patterns and applying location-dependent beamforming weights, the system enhances sound quality from target directions while suppressing noise from other directions, achieving selective isolation of sound sources.
2Measurement precision
If signal processing is applied to steer the microphone array toward a sound source, then the directionality and selectivity of audio capture is improved, but the complexity of the system increases
Solution Approach 1:
The system pre-calculates and stores beamforming weight sets for multiple predetermined directions before actual audio capture. These weight sets are configured in advance based on the microphone array geometry and desired coverage directions. During operation, the system simply selects and applies the appropriate pre-computed weight set, avoiding complex real-time calculations and reducing system complexity while maintaining high directionality.
Solution Approach 2:
The patent implements dynamic switching between different pre-configured beamforming weight sets based on detected sound source location or camera orientation. The system can adaptively change the steering direction by selecting appropriate weight sets, providing dynamic directional control without requiring complex real-time optimization algorithms.
3Area of stationary object
If multiple microphones are used to improve sound capture from different positions, then the spatial coverage is improved, but the difficulty of matching amplitude and phase across microphones increases
Solution Approach 1:
The system performs self-calibration by automatically measuring the amplitude and phase characteristics of each microphone during an initialization phase. The calibration process captures test signals from known positions and computes correction factors for each microphone. These self-determined correction factors are then applied to compensate for manufacturing variations, eliminating the need for high-precision manual matching while maintaining wide spatial coverage.
4Speed
If real-time signal processing is performed to steer and focus sound, then the responsiveness and control flexibility is improved, but the computational requirements and processing time increase
Solution Approach 1:
The system pre-computes beamforming weight sets for multiple predetermined directions and stores them in memory before actual audio capture. During real-time operation, the system only needs to select and apply the appropriate pre-computed weight set based on the current target direction, avoiding complex real-time signal processing calculations. This approach maintains high responsiveness while significantly reducing computational requirements and energy consumption.
Data Source
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AI summary
Method and system for digitally directive focusing and steering of sampled sound within a target area for producing a selective audio output accompanying video. In a preferred embodiment, the method and system is characterized by receiving position and focus data from one or more cameras shooting an event, and use this input data for generating relevant sound output together with the picture.