Ultrasonic Ear Scanning for Personalized HRTF in Headsets
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Solution Overview
Problem
Conventional methods for determining personalized head-related transfer functions (HRTFs) are error-prone and fail to accurately account for the unique ear geometries of individuals, leading to suboptimal audio experiences in headsets due to variations in ear size and shape.
Innovation Solution
An audio system uses ultrasonic and sub-ultrasonic beams to scan a user's ear, detecting reflected signals to update a 3D geometry, which is then used to determine a personalized HRTF, and apply an equalization filter to adjust audio parameters for accurate sound perception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (generalized HRTF from database or image-based inference) are used to determine personalized HRTF, then the process is simple and quick, but the accuracy and personalization quality deteriorates due to inability to capture true ear geometry
Solution Approach 1:
The patent replaces physical microphone placement in the ear canal with an acoustic scanning system that uses ultrasonic waves to map ear geometry externally. This substitution eliminates the need for invasive mechanical insertion while capturing the same geometric information needed for accurate HRTF determination.
Solution Approach 2:
The patent changes the measurement parameters from direct acoustic pressure sensing (requiring microphone insertion) to ultrasonic wave reflection analysis. By using ultrasonic frequencies and analyzing reflected wave patterns, the system derives ear geometry parameters without physical intrusion into the ear canal.
2Measurement precision
If microphones are placed inside the ear canal to measure acoustic response, then accurate HRTF can be obtained, but the procedure becomes invasive and uncomfortable for users
Solution Approach 1:
The patent substitutes the mechanical insertion of microphones into the ear canal with a non-contact acoustic scanning method. Ultrasonic transducers emit waves that reflect off ear structures, and the reflected waves are analyzed to reconstruct ear geometry, completely avoiding physical insertion and associated discomfort.
Solution Approach 2:
The patent introduces ultrasonic waves as an intermediary medium to obtain ear geometry information. Instead of directly placing sensors in the ear canal, the system uses ultrasonic waves as a mediator to probe ear structures externally and derive geometric parameters from the reflected wave patterns.
3Ease of manufacture
If generalized HRTF from database is used, then no additional scanning equipment is needed, but the audio experience quality deteriorates due to not accounting for individual ear geometry variations
Solution Approach 1:
The patent performs preliminary ear geometry scanning and HRTF determination during the headset setup phase. By capturing the user's unique ear geometry beforehand and storing the personalized HRTF parameters, the system ensures high-quality audio experience from the first use without requiring repeated scanning or adjustments.
Solution Approach 2:
The patent creates a digital copy or model of the user's ear geometry through ultrasonic scanning. This digital replica captures the unique geometric features of the user's ear canal and structures, which is then used to generate personalized HRTF parameters that accurately represent the user's acoustic characteristics.
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 method provides highly personalized and accurate HRTFs, ensuring high-fidelity audio delivery by considering obstructed ear areas, improving user experience without invasive microphone placement or altering headset design.
Implementation Method 1
detecting a reflected signal generated by an interaction of the ultrasonic beam with the ear
Data Source
AI summary
An audio system includes a plurality of transducers, one or more acoustic sensors, and a controller. The plurality of transducers transmits an ultrasonic beam towards an ear of a user. The one or more acoustic sensors detect a reflected signal generated by an interaction of the ultrasonic beam with the ear. The controller updates a three-dimensional geometry of the ear based on the reflected signal. The controller determines a head-related transfer function (HRTF) for the user based in part on the three-dimensional geometry of the ear.