Voice Processing Apparatus Noise Suppression
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Solution Overview
Problem
In noisy environments, voice processing techniques face challenges with signal discontinuity and increased computation due to frame overlap in voice signal processing, leading to degraded voice communication quality and recognition accuracy.
Innovation Solution
A voice processing apparatus that divides voice signals into overlapping frames, applies windowing functions to attenuate signal ends, and adjusts these functions based on discontinuity judgments to suppress periodic noise without increasing computation, using a combination of first and second windowing units to ensure continuous signal addition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of overlap between successive frames is increased to suppress periodic noise, then the quality of the corrected voice signal is improved, but the number of frames per unit time increases leading to increased computational load
Solution Approach 1:
The patent applies a second windowing function to the corrected frames after inverse orthogonal transform, modifying the signal parameters at frame boundaries. This parameter change suppresses discontinuities and periodic noise without requiring increased frame overlap, thereby maintaining signal quality while reducing computational load compared to increasing overlap amounts.
2Measurement precision
If the number of orthogonal transform and inverse orthogonal transform operations is increased to improve signal processing quality, then the accuracy of noise elimination is improved, but the processing capability of the processor is exceeded
Solution Approach 1:
The patent applies a second windowing function selectively to suppress discontinuities at frame boundaries, providing just enough additional processing to eliminate periodic noise without requiring excessive orthogonal transform operations. This partial action approach maintains noise elimination accuracy while staying within processor capabilities.
3Reliability
If frame-by-frame signal processing is applied to eliminate noise components, then the intelligibility of the speaker's voice is improved, but discontinuity occurs at frame ends leading to periodic noise
Solution Approach 1:
The patent converts the harmful effect of frame boundary discontinuities into a benefit by applying a second windowing function that specifically targets and suppresses the discontinuities. This transforms the problematic frame-ending behavior into an opportunity for controlled signal modification, eliminating periodic noise while preserving voice intelligibility.
Data Source
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Figure 3A~3B
AI summary
A voice processing apparatus includes: a dividing unit which divides a voice signal into frames in such a manner that any two successive frames overlap each other by a predetermined amount; a first windowing unit which multiplies each frame by a first windowing function that attenuates a signal at both ends of the frame; an orthogonal transform unit which computes a frequency spectrum for each frame multiplied by the first windowing function; a frequency signal processing unit which computes a corrected frequency spectrum; an inverse orthogonal transform unit which computes a corrected frame by applying an inverse orthogonal transform to the corrected frequency spectrum; a second windowing unit which multiplies each corrected frame by a second windowing function that attenuates a signal at both ends of the corrected frame; and an addition unit which adds up the each corrected frame multiplied by the second windowing function, sequentially in time order.