Super-wideband Noise Suppression via Band-splitting
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Solution Overview
Problem
Current methods lack effectiveness in noise suppression for super-wideband audio signals, particularly in the high-frequency band, as they struggle to distinguish noise from speech energy, leading to over- or under-suppression, resulting in low-quality noise suppression.
Innovation Solution
A noise suppression system that splits super-wideband input signals into low-frequency and high-frequency bands, performing noise suppression in the frequency domain on the low-frequency band to generate data used for time-domain processing in the high-frequency band, using a time-domain filter bank and frame-based gains to effectively suppress noise without affecting the richer speech sound.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise suppression is applied to the high-frequency band, then noise is reduced, but speech quality deteriorates due to over-suppression or under-suppression
Solution Approach 1:
The patent divides the super-wideband input signal into two separate frequency bands: low-frequency band (L-band) and high-frequency band (H-band). The L-band is processed in the frequency domain while the H-band is processed in the time domain. This segmentation allows different processing strategies to be applied to each band, enabling effective noise suppression in the H-band without degrading speech quality, as the L-band provides reliable speech energy reference that prevents over-suppression.
2Object-affected harmful factors
If noise suppression is applied to super-wideband signals, then noise is reduced, but computational complexity increases
Solution Approach 1:
The patent segments the processing into two distinct paths: frequency domain processing for L-band and time domain processing for H-band. This segmentation allows the system to avoid the high computational complexity of full frequency-domain processing for the entire super-wideband signal, while still achieving effective noise suppression.
Solution Approach 2:
The patent uses an intermediary approach where noise suppression data is generated from the L-band in the frequency domain, then this data serves as a reference for guiding noise suppression in the H-band in the time domain. This intermediary mechanism enables efficient cross-band noise suppression without requiring complex full-band frequency-domain processing.
3Object-affected harmful factors
If full frequency-domain processing is applied to super-wideband signals, then noise suppression is achieved, but computational load increases significantly
Solution Approach 1:
The patent segments the super-wideband signal processing into frequency domain (L-band) and time domain (H-band) components. This segmentation enables the system to perform computationally efficient time-domain processing for the H-band while using frequency-domain processing only for the L-band to generate noise suppression data, significantly reducing overall computational energy requirements compared to full frequency-domain processing.
Data Source
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AI summary
A time-domain filter bank splits a super-wideband input signal into two signal streams, a low-frequency band (L-band) stream and a high-frequency band (H-band) stream. The L-band stream contains the lower frequency components of the received signal, and the H-band stream contains the higher frequency components of the signal. Noise suppression processing performed on the L-band stream in the frequency-domain generates speech/noise probability and gain filter data that is used for noise suppression processing of the H-band stream, which remains in the time-domain.