Personalized HRTF and ITDF Estimation for Spatial Audio
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Solution Overview
Problem
Current 3D sound technology in virtual reality lacks personalization, using a generalized head-related transfer function (HRTF) and interaural time difference function (ITDF) that fails to accurately recreate spatial audio for individuals, leading to errors in sound localization, particularly in elevation and front/rear perception.
Innovation Solution
A method and computer program product that estimate personalized ITDF and HRTF using in-ear microphones and a loudspeaker, with orientation information from a low-end orientation unit, allowing for data capture in any room without precise equipment or calibration, and processing on a standard computing device, enabling accurate sound source localization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a generalized HRTF and ITDF are used for wide audience compatibility, then device complexity is reduced and ease of operation is improved, but measurement precision and sound localization accuracy deteriorate
Solution Approach 1:
The system performs preliminary measurement of the user's individual HRTF and ITDF before actual 3D audio operation. A calibration phase is executed where test signals are played through loudspeakers and recorded by in-ear microphones, storing the measured data for subsequent use. This preliminary action enables personalized audio processing without requiring repeated measurements during operation.
Solution Approach 2:
The system creates a digital copy of the user's acoustic characteristics through measurement. The individual HRTF and ITDF are captured and stored as data sets that can be reused multiple times. This copying approach allows the system to apply personalized audio processing consistently across different sessions without requiring repeated physical measurements.
2Measurement precision
If specialized measurement infrastructure like anechoic chambers is used, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The system replaces expensive, complex specialized measurement infrastructure with inexpensive, readily available components. Standard loudspeakers, consumer-grade in-ear microphones, and ordinary computing devices are used instead of anechoic chambers and professional measurement equipment. The measurement process is designed to be robust to environmental variations, allowing accurate HRTF and ITDF capture in typical room conditions.
Solution Approach 2:
The measurement system is designed to be self-contained and easy to operate without requiring specialized facilities or expert intervention. The calibration process is automated through software that guides the user through head movements and automatically processes the recorded data. This self-service approach eliminates the need for complex infrastructure while maintaining measurement quality.
3Measurement precision
If precise calibration equipment and known positions are required, then measurement precision is improved, but ease of operation and accessibility deteriorate
Solution Approach 1:
The system dynamically adapts to the user's head movements and positions during measurement rather than requiring fixed, pre-determined positions. The software tracks the orientation unit data and adjusts the measurement process accordingly, allowing the user to move their head freely through various orientations. This dynamic approach simplifies operation while maintaining measurement accuracy through real-time data processing.
Solution Approach 2:
The system incorporates feedback mechanisms where the software monitors the quality and completeness of measured data in real-time. Based on this feedback, the system can prompt the user to perform additional head movements or adjust positioning. This feedback loop ensures sufficient data quality is achieved while keeping the process simple and user-friendly, eliminating the need for precise pre-calibration of equipment positions.
Data Source
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AI summary
Method of estimating an individualized head-related transfer function (HRTF) and an individualized interaural time difference function (ITDF) of a particular person, comprising the steps of: a) obtaining a plurality of data sets (Li, Ri, Oi) comprising a left and a right audio sample fromin-ear microphones, and orientation information (Oi) from an orientation unit, measured in a test-arrangement where an acoustic test signal is rendered via a loudspeaker and the person is moving the head; b) extracting interaural time difference values and/or spectral values, and corresponding orientation values; c) estimating a direction of the loudspeaker relative to the head using a predefined quality criterion; d) estimating an orientation of the orientation unit relative to the head; e) estimating the individualized ITDF and the individualized HRTF. A computer program product for performing the method. A data carrier containing the computer program.