Subband Speech Amplification for Noise Intelligibility
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Solution Overview
Problem
Existing audio signal processing technologies face challenges in maintaining high speech intelligibility in noisy environments without increasing overall speech levels, especially in scenarios with additive noise and reverberation.
Innovation Solution
An algorithm that generates modified speech signals by applying different amplification degrees to speech subband signals based on their power levels, using a weighting information generator and signal modifier to adaptively preprocess the speech signal, maximizing intelligibility while keeping the speech level constant, and incorporating time-and-frequency-dependent gain and compression characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simple amplification is applied to the speech signal, then speech intelligibility is improved, but overall speech level becomes excessively high and technical limitations are exceeded
Solution Approach 1:
The speech signal is divided into multiple frequency subbands, and each subband is processed independently with different amplification factors. This segmentation allows selective amplification of specific frequency components that contribute most to intelligibility while limiting overall power increase.
Solution Approach 2:
Different amplification degrees are applied to different speech subbands based on their individual power levels and intelligibility contributions. High-power subbands receive lower amplification while low-power subbands receive higher amplification, optimizing local quality without excessive overall power.
2Device complexity
If equal amplification is applied to all speech subband signals, then processing complexity is reduced, but speech intelligibility in noise is not sufficiently improved
Solution Approach 1:
The amplification factors for each subband are dynamically adjusted based on the instantaneous power levels of the speech subband signals. This dynamic adaptation allows the system to respond to varying speech characteristics and noise conditions, improving intelligibility without excessive complexity.
Solution Approach 2:
The system monitors the power levels of individual speech subbands and uses this feedback information to determine appropriate amplification factors for each subband. This closed-loop approach optimizes intelligibility by continuously adapting to the input signal characteristics.
Data Source
AI summary
An apparatus for generating a modified speech signal from a speech input signal which has a plurality of speech subband signals, the modified speech signal having a plurality of modified subband signals is provided, having: a weighting information generator for generating weighting information for each speech subband signal depending on a signal power of said speech subband signal, and a signal modifier for modifying each speech subband signal by applying the weighting information on said speech subband signal to obtain a modified subband signal. The weighting information generator is configured to generate the weighting information for each of the plurality of speech subband signals, wherein the signal modifier is configured to modify each of the speech subband signals so that a first speech subband signal having a first signal power is amplified with a first degree, and so that a second speech subband signal having a second signal power is amplified with a second degree, the first signal power being greater than the second signal power, and the first degree being lower than the second degree.