Microphone Array Beam Steering for Video Conferencing Audio Clarity
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Solution Overview
Problem
Conferencing systems face challenges in maintaining audio quality due to audio information from off-camera sources being combined with on-camera audio, leading to confusion and reduced intelligibility, as microphone array beamformers typically do not differentiate between sound sources within and outside the camera's field of view.
Innovation Solution
A video conferencing system with a beamformer that controls the microphone array beam to only steer towards sound sources within the camera's field of view, using sound direction of arrival information to determine if a sound source is within or outside the interest area, and attenuating sound energy from outside sources to prevent beam updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the microphone array beamformer captures all audio signals without differentiation, then the quantity of audio information is maximized, but the audio quality and intelligibility deteriorate due to mixing of off-camera and on-camera sounds
Solution Approach 1:
The patent segments the audio field into distinct regions: a first sound field corresponding to the camera's field of view and a second sound field outside the camera's field of view. The beamformer is configured to selectively capture audio from the first sound field while excluding audio from the second sound field, thereby separating relevant audio information from irrelevant audio information.
Solution Approach 2:
The patent applies local quality by directing the beamformer's sensitivity specifically toward the region within the camera's field of view. The beamforming weights are optimized to enhance audio signals originating from directions consistent with the camera's field of view while attenuating signals from other directions, ensuring that audio quality is improved in the region of interest.
2Adaptability or versatility
If the beamformer steers towards all sound sources, then the adaptability of the system is improved, but the audio quality deteriorates by including unwanted off-camera audio
Solution Approach 1:
The patent implements dynamic beam steering by continuously updating the beamformer's direction based on the camera's current field of view. The system dynamically adjusts the beam direction to follow the camera's orientation and zoom level, ensuring that the beam always points toward the region of interest while excluding off-camera areas.
Solution Approach 2:
The patent uses feedback from the camera's field of view information to control the beamformer's steering. The system receives feedback about the camera's current viewing direction and uses this information to adjust the beamforming weights accordingly, creating a closed-loop system that maintains audio quality by continuously aligning the beam with the camera's field of view.
3Ease of operation
If the beamformer captures audio from all directions, then the ease of operation is improved, but the loss of information increases due to mixing of relevant and irrelevant audio
Solution Approach 1:
The patent performs preliminary action by pre-configuring the beamformer to capture only audio from within the camera's field of view. The system proactively filters out off-camera audio before it can mix with the desired audio signals, preventing information loss rather than attempting to separate mixed signals afterward.
Data Source
AI summary
A video conferencing system has a microphone array that operates to receive acoustic signals corresponding to voice activity and to determine that the signals are either from within a sound field of interest and from outside the sound field of interest, and if the signals are from outside the sound field of interest the system attenuates these signals by not steering a microphone array beam towards these signals.