Main Microphone Switching Using Playback-Aware Echo and Noise Analysis
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Solution Overview
Problem
Conventional methods for switching a main microphone in a microphone-loudspeaker integrated device do not consider whether the loudspeaker is playing audio data or not, leading to the selection of microphones with strong echo signals or high noise levels as the main microphone.
Innovation Solution
A method that involves acquiring audio data for playback by the loudspeaker and by each microphone, preprocessing the data to obtain frequency domain energies, and selecting a candidate main microphone based on noise and frequency domain energies to avoid echo and noise, with additional voice activity detection to identify voice signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional RMS-based switching is used to select the microphone with the strongest signal, then the switching simplicity is maintained, but the echo quality deteriorates because the microphone with the strongest echo signal is selected
Solution Approach 1:
The patent changes the selection parameter from simple signal strength (RMS) to a composite evaluation that includes echo cancellation residual energy and signal-to-noise ratio. This parameter transformation allows the system to consider both echo quality and noise levels while maintaining the automated switching process.
Solution Approach 2:
The patent introduces an intermediary evaluation mechanism that assesses multiple factors (echo residual energy, SNR) before selecting the main microphone. This intermediary layer prevents direct selection based solely on signal strength, thereby avoiding echo-prone microphones while still automating the process.
2Device complexity
If signal strength alone is used for microphone selection, then the selection process is simple, but the sound quality deteriorates due to selection of noisy microphones
Solution Approach 1:
The patent transforms the single-parameter selection (signal strength) into a multi-parameter evaluation system that incorporates noise assessment through signal-to-noise ratio calculation. This allows noise level consideration without excessively complicating the selection process.
Solution Approach 2:
The patent performs preliminary noise characterization by calculating the noise floor for each microphone before making the selection decision. This preliminary action enables the system to account for noise levels in the final selection without adding significant complexity to the overall process.
3Speed
If main microphone switching is performed without considering loudspeaker playback state, then the switching response speed is fast, but the echo suppression performance deteriorates
Solution Approach 1:
The patent performs preliminary assessment of echo residual energy and signal-to-noise ratio before triggering the main microphone switch. This preliminary evaluation ensures that switching decisions are made with knowledge of the current acoustic environment, improving echo suppression without significantly delaying the response.
Solution Approach 2:
The patent incorporates feedback from the echo cancellation system by utilizing the residual echo energy as a selection criterion. This feedback mechanism allows the switching decision to be informed by the actual echo suppression performance, thereby improving overall echo management while maintaining responsive switching.
Data Source
AI summary
A method and apparatus for switching a main microphone of a plurality of microphones, a voice detection method and apparatus for a microphone, a microphone-loudspeaker integrated device, and a readable storage medium are provided. The method for switching the main microphone of the plurality of microphones includes: acquiring first audio data for playback by a loudspeaker, and acquiring second audio data acquired by each microphone and corresponding noise frequency domain energy; obtaining corresponding first frequency domain energy and second frequency domain energy according to the first audio data and the second audio data; when the first frequency domain energy is less than a first preset threshold, selecting a candidate main microphone according to the noise frequency domain energy and the second frequency domain energy corresponding to each microphone; and switching the candidate main microphone as a main microphone.