Dual Microphone Sensitivity Calibration for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dual-microphone noise reduction methods in mobile phones face issues due to inconsistency in sensitivity between primary and secondary microphones, caused by aging, blockage, or malfunction, which deteriorates noise reduction effectiveness.
Innovation Solution
A sensitivity calibration method that determines a calibration gain based on signals captured by both microphones, calibrating the secondary microphone to match the sensitivity of the primary microphone, ensuring consistent sensitivity and improved noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If dual-microphone noise reduction is implemented using energy difference, then noise reduction effectiveness is improved, but sensitivity inconsistency between microphones deteriorates the effect
Solution Approach 1:
The patent applies preliminary action by performing sensitivity calibration before noise reduction processing. The system pre-calibrates the secondary microphone's sensitivity relative to the primary microphone using calibration signals, storing calibration gains that are later applied during actual noise reduction operations. This ensures sensitivity consistency is established in advance, preventing degradation of noise reduction effectiveness.
Solution Approach 2:
The patent implements feedback by continuously monitoring the energy difference between primary and secondary microphones and adjusting calibration gains accordingly. The system calculates calibration gains based on the ratio of energies from both microphones and applies these gains to compensate for sensitivity inconsistencies, creating a closed-loop system that maintains optimal performance.
2Reliability
If sensitivity calibration is performed continuously, then sensitivity consistency is improved, but computational complexity and processing time increase
Solution Approach 1:
The patent applies periodic action by performing sensitivity calibration at specific intervals or under specific conditions rather than continuously. The system calibrates using calibration signals at predetermined moments (such as during device initialization or when noise patterns suggest recalibration is needed), reducing computational complexity while maintaining adequate sensitivity consistency for normal operation.
3Measurement precision
If calibration gain is adjusted frequently, then noise reduction accuracy is improved, but system stability deteriorates due to oscillations
Solution Approach 1:
The patent applies beforehand cushioning by introducing smoothing mechanisms and constraints on calibration gain adjustments before they are applied. The system limits the rate of change of calibration gains and applies smoothing filters to prevent oscillations, cushioning against potential instability while still allowing sufficient adjustment for accurate noise reduction.
Data Source
AI summary
Embodiments of the present invention disclose a sensitivity calibration method and an audio device. The method of the present invention includes determining whether a first signal captured in a current frame by a primary capture module is a circuit noise. When the first signal is not a circuit noise, if the first signal has a stationary noise characteristic, a first calibration gain is determined according to the first signal and a second signal captured in the current frame by a secondary capture module. The second signal is calibrated according to the first calibration gain, so that sensitivity of the primary capture module is consistent with sensitivity of the secondary capture module.