Hearing Protection Voice Estimation Using Segmented Adaptive Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In noisy environments, hearing protection systems face challenges in accurately detecting and isolating a user's voice signal from ambient noise and audio outputs, leading to inefficient communication and potential hearing damage.
Innovation Solution
A hearing protection system incorporating a communication unit, ear canal microphone, receiver, and a compensation module with a static primary filter and adaptive secondary filter, where the filter controller adjusts secondary filter coefficients based on the voice signal and primary filter output to enhance voice signal estimation and reduce computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an adaptive filter is used to estimate the user's own voice, then the accuracy of voice signal estimation is improved, but the computational complexity and power consumption increase
Solution Approach 1:
The patent divides the adaptive filter into two separate filters: a first adaptive filter that processes the audio output signal to generate a compensation signal, and a second adaptive filter that processes the ear canal input signal using the compensation signal. This segmentation allows each filter to operate with reduced computational requirements compared to a single full-length adaptive filter, thereby reducing power consumption while maintaining voice estimation accuracy.
Solution Approach 2:
The patent extracts and removes the known playback path characteristics (through the first adaptive filter processing the audio output signal) from the overall estimation problem. By taking out this known component as a separate compensation signal, the second adaptive filter only needs to estimate the remaining unknown components, reducing its computational burden and power consumption while preserving estimation accuracy.
2Measurement precision
If a longer filter length is used, then the voice signal estimation accuracy is improved, but the convergence time increases and computational complexity rises
Solution Approach 1:
The patent segments the filtering task across two parallel adaptive filters with shorter lengths rather than using one long filter. Each filter processes a portion of the signal with reduced tap length, enabling faster convergence while the combined output achieves the same overall estimation accuracy that would require a much longer single filter.
Solution Approach 2:
The first adaptive filter performs preliminary processing of the audio output signal to generate the compensation signal before the second adaptive filter processes the ear canal input signal. This preliminary action removes known playback path effects in advance, allowing the second filter to converge faster by focusing only on the remaining unknown components rather than processing the entire signal from scratch.
3Measurement precision
If the adaptive filter processes the full audio signal, then complete voice estimation is achieved, but numerical saturation occurs and computation becomes more complex
Solution Approach 1:
The patent extracts the compensation signal representing the known playback path characteristics from the full audio signal processing chain. By taking out this known component separately through the first adaptive filter, the second adaptive filter processes a simplified signal with reduced dynamic range and fewer numerical issues, avoiding saturation while maintaining complete voice estimation through the combination of both filter outputs.
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present disclosure provides a hearing protection system and a method for estimating a voice signal of a hearing protection system user. The hearing protection system comprises an ear canal microphone for provision of an ear canal input signal; a receiver for provision of an audio output signal; a compensation module for receiving and filtering the ear canal output signal for provision of a compensation signal; and a mixer connected to the ear canal microphone and the compensation module for provision of a voice signal, wherein the compensation module comprises a filter controller, a primary filter and a secondary filter, wherein the primary filter is a static filter, wherein primary filter coefficients of the primary filter are static, and wherein the secondary filter is an adaptive filter, wherein secondary filter coefficients of the secondary filter are controlled by the filter controller based on the voice signal