Voice Assistant Speech Pre-Processing for Linear Gain Adaptation
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Solution Overview
Problem
Voice interactive Intelligent Personal Assistants face challenges in properly interpreting speech with varying sound pressure levels, as existing systems struggle to effectively preprocess audio signals to optimize recognition without introducing non-linear distortions.
Innovation Solution
A method and system for linearly pre-processing input audio signals by detecting a voice trigger, calculating a gain factor based on signal parameters, and applying it to ensure output signals are within a desired range, thereby preventing non-linear distortions and enhancing speech recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-linear processing (such as compression or expansion) is applied to audio signals to adjust dynamic range, then the audio signal can be adapted to fit within a limited dynamic range, but non-linear distortions are introduced that hamper speech recognition
Solution Approach 1:
The patent changes the processing approach from non-linear to linear operations. Instead of using non-linear compression/expansion, the system uses linear gain adjustment where output = input × gain_factor. The gain factor is calculated based on the ratio of desired average level to actual average level, maintaining linearity while achieving dynamic range adaptation, thus avoiding introduction of non-linear distortions that would harm speech recognition accuracy
2Stability of the object's composition
If the dynamic range of audio signals is reduced to fit within a limited range, then the system can process signals more consistently, but speech signals with varying sound pressure levels cannot be properly interpreted
Solution Approach 1:
The patent implements dynamic gain adjustment where the gain factor is calculated for each audio signal based on its specific characteristics (average level, desired level). This allows the system to adapt to varying sound pressure levels dynamically while maintaining consistent processing through linear operations. The dynamic range is preserved by applying different linear gain factors rather than compressing the range, enabling proper interpretation of speech signals with varying levels while maintaining processing consistency
3Measurement precision
If audio signals are amplified or attenuated to desired levels, then speech recognition can be improved, but non-linear distortions may be introduced
Solution Approach 1:
The patent replaces non-linear mechanical processing (compression/expansion) with linear mathematical operations (multiplication by gain factor). The linear gain adjustment substitutes the non-linear distortion-generating mechanism with a linear alternative that achieves the same level adjustment goal without introducing harmful non-linear distortions, thereby improving speech recognition precision while avoiding distortion generation
Data Source
AI summary
A method for speech level adaptation, the method includes: (A) Receiving, by a voice interactive intelligent personal assistant, multiple input audio signals that includes first and second groups of input audio signals. (B) Buffering the multiple input audio signals. (C) Searching for a voice trigger in the first group of input audio signals. When finding the voice trigger then (D) Determining a linear gain factor to be applied on the second group of buffered audio signals, (E) Applying the linear gain factor on the second group of buffered audio signals to provide the output audio signals; and (F) applying a speech recognition process on the output audio signals to detect an audio command embedded in the output audio signals.