Personalized HRTF Generation Using Handheld Audio and In-Ear Microphones
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Solution Overview
Problem
Current methods for generating personalized head-related transfer functions (HRTFs) are costly and time-consuming, often requiring expensive equipment like anechoic chambers, and are not practical for timely generation for individual users.
Innovation Solution
A method using a handheld device to output audio signals at various locations, allowing users to move the device to different positions while detecting audio with in-ear microphones, which then generates lower-quality HRTF features based on interaural time and level differences, and spectral cues, subsequently mapped to high-quality HRTFs using machine learning, eliminating the need for anechoic chambers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HRTFs are measured in an anechoic chamber, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses in-ear microphones as an intermediary measurement tool that can capture HRTF data directly in the user's ear canal, eliminating the need for complex anechoic chamber environments. The microphones serve as a portable, simplified intermediary device that enables accurate HRTF measurement in ordinary settings.
Solution Approach 2:
The patent replaces the mechanical/acoustic complexity of an anechoic chamber with an electronic measurement system using in-ear microphones and digital signal processing. The physical anechoic chamber structure is substituted with electronic capture and processing of acoustic signals.
2Productivity
If HRTFs are measured for select test subjects and adapted to other subjects, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent enables each user to generate their own personalized HRTF data through self-measurement using in-ear microphones. Users simply insert the microphones and follow automated guidance to capture their unique acoustic characteristics, eliminating the need for adaptation from test subjects while maintaining high productivity through automation.
Solution Approach 2:
The system performs preliminary measurements of the user's ear canal acoustics using in-ear microphones before generating personalized HRTFs. This preliminary capture of individual anatomical acoustic characteristics enables subsequent rapid generation of accurate personalized HRTFs without time-consuming adaptation processes.
3Measurement precision
If traditional HRTF measurement methods are used, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent uses periodic impulse signals (click trains or swept sine waves) played through headphones to efficiently stimulate the acoustic system. These periodic signals enable rapid capture of HRTF data across multiple frequencies and directions in a single measurement session, dramatically reducing measurement time while maintaining precision.
Solution Approach 2:
The measurement process continuously captures acoustic responses across multiple frequencies, directions, and time points without interruption. The in-ear microphones continuously record the impulse response as the user moves through different head positions, maximizing data collection efficiency and minimizing measurement time.
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
Enables the generation of high-quality HRTFs in a non-anechoic environment, providing accurate sound localization without the need for expensive equipment, allowing for timely and cost-effective personalized audio experiences in immersive applications like VR.
Implementation Method 1
the interaural time difference and interaural intensity variations for a sound (that is, the time difference between receiving the sound at each ear, and the difference in perceived volume at each ear)
Implementation Method 2
the interaural time difference and interaural intensity variations for a sound
Implementation Method 3
An audio signal is generated for output by a handheld device
Data Source
AI summary
A method of obtaining a head-related transfer function for a user is provided. The method comprises generating an audio signal for output by a handheld device and outputting the generated audio signal at a plurality of locations by moving the handheld device to those locations. The audio output by the handheld device is detected at left-ear and right-ear microphones. A pose of the handheld device relative to the user's head is determined for at least some of the locations. One or more personalised HRTF features are then determined based on the detected audio and corresponding determined poses of the handheld device. The one or more personalised HRTF features are then mapped to a higher-quality HRTF for the user, wherein the higher-quality HRTF corresponds to an HRTF measured in an anechoic environment. This mapping may be learned using machine learning, for example. A corresponding system is also provided.