Noise Suppression Gain Limiting for Voice Hoarseness Reduction
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Solution Overview
Problem
Existing noise suppressing apparatuses often excessively suppress high-frequency bands, leading to voice hoarseness due to increased sensitivity in higher frequency bands, which affects the signal-to-noise ratio (SNR) and results in inadequate noise suppression performance.
Innovation Solution
A noise suppressing apparatus that converts temporal waveforms into frequency components, calculates band power and noise power, and adjusts gains for noise suppression, incorporating an upper limit value for noise suppression amount in each frequency band to prevent excessive noise reduction, thereby maintaining effective noise suppression while reducing voice hoarseness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noise suppression gain is increased to suppress noise effectively, then noise suppression performance is improved, but voice hoarseness occurs due to excessive suppression in high-frequency bands
Solution Approach 1:
The patent applies different noise suppression gains to different frequency bands based on their characteristics. High-frequency bands receive limited suppression to preserve voice quality, while low-frequency bands receive stronger suppression to effectively remove noise. This local differentiation resolves the contradiction by preventing excessive suppression in high-frequency bands that causes voice hoarseness, while maintaining effective noise suppression in other bands.
Solution Approach 2:
The patent dynamically adjusts the noise suppression gain parameter based on the signal-to-noise ratio (SNR) and frequency band. When SNR is high, suppression gain is reduced to avoid over-suppression and voice hoarseness. When SNR is low, suppression gain is increased to improve noise reduction effectiveness. This parameter adaptation allows the system to optimize noise suppression performance while preventing harmful effects in high-frequency bands.
2Reliability
If noise suppression gain is increased to improve signal-to-noise ratio, then noise suppression performance is improved, but excessive noise reduction occurs in high-frequency bands
Solution Approach 1:
The patent applies different noise suppression gains to different frequency bands based on their characteristics. High-frequency bands receive limited suppression to preserve voice quality, while low-frequency bands receive stronger suppression to effectively remove noise. This local differentiation resolves the contradiction by preventing excessive suppression in high-frequency bands that causes voice hoarseness, while maintaining effective noise suppression in other bands.
Solution Approach 2:
The patent applies partial noise suppression rather than excessive suppression, especially in high-frequency bands. By calculating an upper limit value for noise suppression amount and comparing it with the desired suppression gain, the system applies only the necessary amount of suppression to achieve effective noise reduction without over-suppressing high-frequency components that would cause distortion and voice hoarseness.
Data Source
AI summary
According to an aspect of the invention, there is provided a noise suppressing apparatus comprising: a fifth unit configured to calculate a gain for noise suppression, based on the first signal-to-noise ratio for each frequency band and the second signal-to-noise ratio for an entire frequency band; an eighth unit configured to calculate an upper limit value of a noise suppression amount for each frequency band, based on the second signal-to-noise ratio; a ninth unit configured to calculate the noise suppression amount for each frequency band, based on the first signal-to-noise ratio; and a tenth unit configured to limit, based on the upper limit value, the noise suppression amount so as to calculate the gain.