Dynamic Residual Noise Shaping for Audio Signal Hiss Reduction
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Solution Overview
Problem
Conventional noise reduction methods in signal processing create audible artifacts and fail to effectively reduce high-frequency hiss noise in wideband microphone recordings, as they apply uniform noise attenuation across all frequencies, impairing both hiss noise reduction and low-frequency audio quality.
Innovation Solution
A dynamic residual noise shaping system that detects hiss noise and applies a dynamic attenuation floor to adjust high-frequency noise shapes, using subband analysis, hiss detection, and adaptive noise suppression gains to constrain residual noise to a target shape, improving noise reduction while maintaining audio quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform noise attenuation is applied across all frequencies, then noise reduction is achieved, but high-frequency hiss noise and low-frequency audio quality are both impaired
Solution Approach 1:
The patent applies different noise suppression gains to different frequency bands. Specifically, it implements a dynamic attenuation floor that selectively constrains residual noise in high-frequency bands where hiss noise occurs, while allowing low-frequency bands to maintain their original audio quality. This local differentiation resolves the contradiction by targeting noise reduction only where necessary (high frequencies) rather than uniformly across all frequencies.
Solution Approach 2:
The patent segments the frequency spectrum into different bands and applies independent noise suppression control to each band. By dividing the frequency range and applying band-specific attenuation floors, the system can reduce hiss noise in high-frequency segments while preserving audio quality in low-frequency segments, thus resolving the contradiction between noise reduction and audio quality preservation.
2Reliability
If noise suppression gains are increased to reduce hiss noise, then high-frequency noise is reduced, but audible artifacts are introduced
Solution Approach 1:
The patent employs a dynamic attenuation floor that is adaptively adjusted based on the detected residual noise characteristics. The system continuously monitors the noise spectrum and adjusts the attenuation floor level accordingly, increasing suppression when hiss noise is detected and reducing suppression when artifacts begin to appear. This feedback mechanism resolves the contradiction by dynamically balancing noise reduction effectiveness against artifact introduction.
Data Source
AI summary
A system and method for dynamic residual noise shaping configured to reduce hiss noise in an audio signal. The system and method may detect an amount and type of hiss noise. The system and method may limit calculated noise suppression gains responsive to the detected amount and type of hiss noise. The limited noise suppression gains may be applied to the audio signal and may reduce the hiss noise.