Audio Image Localization Correction for Environmental Noise
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Solution Overview
Problem
Existing sound localization techniques face challenges in accurately measuring transfer characteristics outside a controlled measurement room, particularly due to unwanted reflections and background noise, which degrades measurement accuracy.
Innovation Solution
A sound localization device and method that includes left and right speakers, microphones, a transfer characteristics measurement unit, a convolution calculation unit, an environmental measurement unit, and a correction unit to measure and correct transfer characteristics in various environments, setting appropriate amplitude levels and tap lengths based on environmental measurements to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transfer characteristics are measured in a non-measurement room environment, then measurement convenience and adaptability are improved, but measurement precision deteriorates due to reflections and background noise
Solution Approach 1:
The system performs preliminary environmental measurements before actual transfer characteristics measurement to identify and characterize unwanted sounds (reflections, background noise). This preliminary action allows the system to prepare correction parameters in advance, enabling accurate measurements even in non-ideal environments.
Solution Approach 2:
The system converts unwanted environmental sounds (reflections, background noise) from harmful factors into useful information. By measuring and analyzing these unwanted sounds, the system generates correction parameters that compensate for their effects, thereby improving measurement accuracy in real-world environments.
2Measurement precision
If microphones are placed at the entrances of ear canals for accurate measurement, then measurement precision is improved, but device complexity and ease of operation worsen
Solution Approach 1:
The system uses headphones as an intermediary to copy and transfer the acoustic characteristics from the speaker to the ear canal entrance. Instead of placing microphones directly at the ear canal entrances, the system measures transfer characteristics through the headphone path, which can be easily connected and disconnected without complex setup procedures.
3Measurement precision
If environmental measurements are performed to correct for noise and reflections, then measurement precision is improved, but measurement time and processing complexity increase
Solution Approach 1:
The system performs partial correction by focusing primarily on low-frequency range corrections where environmental noise and reflections have the most significant impact. This selective approach achieves substantial improvement in measurement accuracy without requiring complete correction across all frequency ranges, thereby reducing processing time.
Data Source
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AI summary
A transfer characteristics measurement unit (35) measures first transfer characteristics from left and right speakers (5L, 5R) to left and right microphones (2L, 2R), respectively. Convolution calculation units (11, 12, 21, 22) perform a convolution calculation on a reproduction signal by using the first transfer characteristics. An environmental measurement unit (39) picks up environmental measurement signals output from the left and right speakers (5L, 5R) with use of the left and right microphones (2L, 2R), sets an amplitude level of transfer characteristics measurement signals and a tap length of the transfer characteristics, picks up sounds with use of the left and right microphones (2L, 2R) in a state where no sound is output from the left and right speakers (5L, 5R), and measures second transfer characteristics. A correction unit (38) corrects a low frequency range of the first transfer characteristics based on the second transfer characteristics.