Speech Signal Bandwidth Extension Loudness Sharpness Compensation
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Solution Overview
Problem
Modern audio codecs using bandwidth extension schemes often result in reconstructed high-frequency bands with reduced perceived loudness and sharpness, leading to a decrease in subjective audio quality due to artifacts.
Innovation Solution
A method and system that separate a speech signal into low and high frequency bands, adapt the low frequency band to emphasize specific frequencies, and reconstruct the high frequency band based on the adapted low frequency band to improve perceived loudness and sharpness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bandwidth extension scheme is applied to reconstruct high frequency bands, then transmission efficiency is improved, but perceived loudness and sharpness decrease
Solution Approach 1:
The patent applies parameter changes by modifying the frequency content of the low frequency band through filtering before using it for bandwidth extension. Specifically, the low frequency band is filtered to emphasize certain frequency ranges, which changes the spectral parameters of the signal. This allows the reconstructed high frequency band to have enhanced perceived loudness and sharpness while maintaining the efficiency benefits of bandwidth extension.
2Productivity
If bandwidth extension scheme is applied to reconstruct high frequency bands, then transmission efficiency is improved, but perceived sharpness decreases
Solution Approach 1:
The patent changes the spectral parameters of the low frequency band by applying filters that emphasize specific frequency ranges. This parameter modification ensures that when the high frequency band is reconstructed from the modified low frequency band, the resulting signal has enhanced sharpness characteristics while maintaining transmission efficiency.
3Illumination intensity
If low frequency band is filtered to emphasize specific frequencies, then perceived loudness and sharpness are improved, but signal processing complexity increases
Solution Approach 1:
The patent segments the frequency spectrum into distinct bands (low frequency band and high frequency band) and applies different processing operations to each. By separating the signal processing into discrete stages - filtering the low frequency band, then using it to reconstruct the high frequency band - the system manages complexity through structured segmentation rather than monolithic processing.
Data Source
AI summary
In a method of improving perceived loudness and sharpness of a reconstructed speech signal delimited by a predetermined bandwidth, performing the steps of providing (S10) the speech signal, and separating (S20) the provided signal into at least a first and a second signal portion. Subsequently, adapting (S30) the first signal portion to emphasize at least a predetermined frequency or frequency interval within the first bandwidth portion. Finally, reconstructing (S40) the second signal portion based on at least the first signal portion, and combining (S50) the adapted first signal portion and the reconstructed second signal portion to provide a reconstructed speech signal with an overall improved perceived loudness and sharpness.