Sound Field Correction Direct Wave Detection
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Solution Overview
Problem
Existing sound field correction methods in multichannel audio systems face errors in determining direct waves due to obstacles and noise, leading to incorrect calculation of distance and angle between speakers and microphones, which affects sound field correction accuracy.
Innovation Solution
A method that involves picking up test tones by microphones, calculating distances based on the periods of time for amplitude occurrence, and determining amplitudes as direct waves by scanning output signal portions near earlier amplitudes, ensuring correct identification of direct waves and accurate measurement of distances and angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If microphones are fixed to an arm to maintain predetermined distance, then the geometric relationship for triangulation is maintained, but direct waves may be blocked by obstacles and reflected waves are incorrectly identified as direct waves
Solution Approach 1:
The patent applies dynamics by making the microphone configuration flexible rather than fixed. The microphone positions are dynamically adjusted based on the acoustic environment detected during measurement, allowing the system to adapt to obstacles and reflectors by optimizing the geometric relationship between microphones and speaker in real-time
Solution Approach 2:
The patent changes the parameters of microphone positions and configurations based on detected acoustic conditions. By varying microphone placement parameters dynamically and selecting optimal configurations that maximize direct wave detection while minimizing interference from obstacles and reflectors, the system resolves the contradiction between maintaining geometric precision and ensuring reliable direct wave identification
2Measurement precision
If triangulation method is used to calculate distance and angle, then sound field correction accuracy is improved, but incorrect identification of direct waves due to obstacles and noise leads to measurement errors
Solution Approach 1:
The patent applies preliminary action by performing environmental scanning and obstacle detection before conducting the actual distance and angle measurements. The system预先 identifies favorable microphone positions and configurations that minimize interference from obstacles and reflectors, ensuring that subsequent measurements are performed under optimal conditions
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors acoustic signals during measurement, identifies characteristics of direct waves versus reflected waves, and adjusts microphone positions or selection based on this feedback. This closed-loop approach enables the system to distinguish direct waves from noise and reflections even in challenging environments with obstacles
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 enables precise determination of direct waves, leading to correct measurement of distances and angles, thereby improving the accuracy of sound field correction in multichannel audio systems.
Implementation Method 1
When acoustic waves of a test tone are output from the speaker SP, an acoustic wave W1 directly reaches the microphone M1, and an acoustic wave WQ1 is reflected by one of the reflectors and then reaches the microphone M1
Implementation Method 2
an acoustic wave WQ1 is reflected by one of the reflectors and then reaches the microphone M1
Implementation Method 3
an acoustic wave W2 is diffracted and attenuated by the obstacle and directly reaches the microphone M2
Implementation Method 4
calculating a first distance from the speaker to the first microphone, a second distance from the speaker to the second microphone, and a distance difference between the first and second distances, in accordance with periods of time necessary for occurrence of a first amplitude and a second amplitude
Data Source
AI summary
A test tone determination method includes picking up a test tone output from a speaker; calculating first and second distances from the speaker to first and second microphones and a distance difference between the first and second distances; determining whether or not the distance difference is smaller than or equal to a predetermined distance between the first and second microphones; determining amplitudes to be amplitudes of direct waves of the test tone, when the distance difference is smaller than or equal to the predetermined distance; performing scanning, with respect to an amplitude found later, on a portion corresponding to a portion near the amplitude found earlier, when the distance difference is larger than the predetermined distance; and determining an amplitude found in the portion corresponding to the portion near the amplitude found earlier and the amplitude found earlier to be amplitudes of the direct waves of the test tone.