Personalized HRTF Filter Generation via Pinna Reflection Measurement
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Solution Overview
Problem
Existing binaural audio reproduction methods use non-individualized head-related transfer functions (HRTFs) and headphone equalization (HpEQ) filters, leading to inaccurate sound positioning and quality issues for different users, as these filters are highly user-specific and cannot effectively simulate sound sources at the same location for all listeners.
Innovation Solution
An audio system and method to determine personalized HRTFs or HpEQ filters for each user by measuring the user-specific acoustic transfer function using a headphone's speaker and microphone, which is then used to generate a spatial audio signal that accurately simulates external sound sources in a soundscape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-individualized HRTFs or HpEQ filters are used, then the device complexity is reduced and ease of operation is improved, but the accuracy of sound positioning and quality of virtual sound sources deteriorate
Solution Approach 1:
The system automatically measures the user-specific acoustic transfer function by playing test tones through the headphone speaker and capturing the reflected sound through the headphone microphone. The acoustic transfer function is then automatically inverted to generate personalized HRTF or HpEQ filters without requiring manual user input or configuration, enabling the system to serve itself in the customization process
Solution Approach 2:
The system changes the acoustic transfer function parameters by measuring the actual sound reflections specific to each user's anatomy and using these measured parameters to generate personalized filters. This transforms the fixed, generic filter parameters into dynamic, user-specific parameters that adapt to individual acoustic characteristics
2Ease of manufacture
If non-individualized HRTFs or HpEQ filters are used, then the ease of manufacture is improved, but the reliability of binaural reproduction deteriorates
Solution Approach 1:
The system performs self-characterization by automatically measuring the user's acoustic transfer function without requiring external calibration equipment or manual setup. The headphone's own speaker and microphone are used to capture user-specific acoustic information, eliminating the need for complex external measurement systems while ensuring reliable reproduction
Solution Approach 2:
The system uses feedback from the microphone capturing the reflected sound to determine the acoustic transfer function. This feedback loop allows the system to adapt the audio filters based on actual measured acoustic characteristics, ensuring reliable binaural reproduction that matches the user's specific anatomical features
3Manufacturing precision
If user-specific acoustic transfer function measurement is performed, then the accuracy of binaural reproduction is improved, but the measurement time and processing complexity increase
Solution Approach 1:
The system performs the acoustic transfer function measurement during the initial setup or calibration phase, storing the measured data for use in subsequent audio reproduction. This preliminary action eliminates the need for repeated measurements during actual audio playback, reducing time loss during the main usage period
Solution Approach 2:
The system uses the headphone's built-in speaker and microphone to perform self-measurement of the acoustic transfer function, eliminating the need for external measurement equipment. This self-service approach streamlines the measurement process and reduces the time required compared to traditional external measurement methods
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
The personalized audio filters provide an accurate binaural reproduction, improving the perceived position and quality of virtual sound sources, ensuring each user experiences a realistic rendering of spatial audio.
Implementation Method 1
a microphone of the headphone can detect the sound after the sound reflects from a pinna of the user
Data Source
AI summary
An audio system and a method of using the audio system to determine one or more of a head-related transfer function (HRTF) or a headphone equalization (HpEQ) filter for a user, are described. The audio system can determine an acoustic transfer function that relates an output signal detected by a microphone of a headphone worn by the user to an in input signal played by a speaker of the headphone. The acoustic transfer function corresponds to sound reflecting from a pinna of the user between the speaker and the microphone, and accordingly, the acoustic transfer function is user-specific. The user-specific acoustic transfer function can be used to determine the HRTF or the HpEQ filter for the user. Other aspects are also described and claimed.