Dynamic Phase Range Adjustment for Voice Direction Identification
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Solution Overview
Problem
Existing voice processing systems using multiple microphones struggle to accurately estimate the direction of a sound source due to differences in microphone characteristics and environmental factors, leading to incorrect suppression or enhancement of desired sounds.
Innovation Solution
A voice processing apparatus that transforms voice signals into frequency domain signals, calculates phase differences, and adjusts the suppression range based on the percentage of phase differences within a specific range to correctly identify and enhance sounds from a specific direction, while expanding the non-suppression range for frequency bands with low achieved rates to account for variations caused by microphone differences or environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed phase difference range is used for sound source direction identification, then the processing is simple and fast, but the accuracy deteriorates due to microphone characteristic differences and environmental factors
Solution Approach 1:
The patent applies dynamics by making the phase difference range adjustable rather than fixed. The control unit dynamically adjusts the phase difference range based on the achieved rate calculated from actual microphone signals. When the achieved rate is low (indicating poor matching due to microphone characteristics or environment), the system automatically expands the phase difference range to maintain accurate sound source direction identification.
Solution Approach 2:
The patent changes the parameter of phase difference range based on the achieved rate. By calculating the achieved rate from actual microphone signals and using it to adjust the phase difference range, the system adapts to different microphone characteristics and environmental conditions, thereby improving identification accuracy without requiring complete redesign of the processing architecture.
2Measurement precision
If the phase difference range is expanded to account for variations, then the accuracy improves, but the specificity deteriorates leading to potential misidentification of sound source direction
Solution Approach 1:
The system dynamically adjusts the phase difference range based on the achieved rate. When the achieved rate is high (good matching), the system uses a narrower phase difference range to maintain high specificity and avoid misidentification. When the achieved rate is low (poor matching due to microphone characteristics or environment), the system expands the range to improve accuracy. This dynamic adjustment maintains both accuracy and reliability across different conditions.
Solution Approach 2:
The patent implements feedback by calculating the achieved rate from actual microphone signals and using this feedback to adjust the phase difference range. The achieved rate serves as a feedback indicator of how well the current phase difference range matches the actual sound source direction. This feedback mechanism allows the system to automatically optimize the balance between accuracy and reliability based on real-time conditions.
3Reliability
If a narrow phase difference range is used, then the specificity is high reducing misidentification, but the accuracy deteriorates due to microphone characteristic differences
Solution Approach 1:
The patent changes the phase difference range parameter based on the achieved rate calculated from actual microphone signals. Instead of using a fixed narrow range that may not account for microphone characteristics, the system adjusts the range width according to the achieved rate, thereby maintaining both reliability and accuracy across different operating conditions.
4Measurement precision
If the achieved rate calculation is performed for all frequency bands, then the accuracy improves, but the processing time increases
Solution Approach 1:
The patent applies local quality by performing achieved rate calculation and phase difference range adjustment only for frequency bands where it is necessary. Instead of uniformly processing all frequency bands with the same level of detail, the system can focus computational resources on frequency bands that contribute most to accurate sound source direction identification, thereby reducing overall processing time while maintaining accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively attenuates unwanted sounds from other directions, ensuring that the desired sound from the target direction is enhanced, improving sound clarity and accuracy in voice processing systems.
Implementation Method 1
a time-frequency transforming unit that transforms a first voice signal representing a sound captured by a first voice input unit and a second voice signal representing a sound captured by a second voice input unit, respectively, into a first frequency signal and a second frequency signal in a frequency domain
Data Source
AI summary
A voice processing apparatus includes: a phase difference calculation unit which calculates for each frequency band a phase difference between first and second frequency signals obtained by applying a time-frequency transform to sounds captured by two voice input units; a detection unit which detects a frequency band for which the percentage of the phase difference falling within a first range that the phase difference can take for a specific sound source direction, the percentage being taken over a predetermined number of frames, does not satisfy a condition corresponding to a sound coming from the direction; a range setting unit which sets, for the detected frequency band, a second range by expanding the first range; and a signal correction unit which makes the amplitude of the first and second frequency signals larger when the phase difference falls within the second range than when the phase difference falls outside the second range.