HRTF Map Generation Using Mobile Device Azimuthal Movement
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Solution Overview
Problem
Existing methods for generating datasets of angle-dependent head-related transfer functions (HRTFs) are time-consuming and impractical to perform outside of a laboratory setting, requiring access to specialized and costly facilities.
Innovation Solution
An audio system and method to generate an HRTF map using a mobile device and headphones, which moves along an azimuthal path to emit sounds and detect input signals, allowing for the determination and interpolation/extrapolation of HRTFs to create a comprehensive dataset for spatial audio rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If HRTF measurements are performed using a laboratory HRTF measurement system, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses microphones positioned in the ear canal entrances to capture acoustic signals that copy the natural path sound would take to reach the eardrum. This creates a simplified measurement system that replicates the function of complex laboratory equipment by using the user's own anatomy as the measurement medium, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The system uses the user's own head and ears as part of the measurement apparatus. The microphones are positioned in the user's ear canals, and the user's anatomy naturally provides the acoustic filtering effects that would otherwise require complex artificial structures. This self-service approach eliminates the need for expensive laboratory equipment while maintaining measurement accuracy.
2Measurement precision
If HRTF measurements are performed in a controlled laboratory setting, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
Instead of bringing the user to a laboratory setting for measurements, the patent inverts the approach by bringing the measurement system to the user. The mobile device with microphones can be used in various locations, transforming the measurement process from something that requires the user to travel to a specialized facility into something that comes to the user, thereby dramatically improving ease of operation.
Solution Approach 2:
The system allows for dynamic measurement collection where the mobile device can move around the user's head to capture HRTF data from multiple angles and positions. This dynamic approach enables comprehensive HRTF measurement without requiring a fixed laboratory setup, making the process more accessible and easier to perform in various environments.
3Adaptability or versatility
If complete azimuthal HRTF coverage is achieved through mobile device movement, then adaptability is improved, but measurement time increases
Solution Approach 1:
The system employs periodic action by having the mobile device move around the user's head in a systematic pattern, emitting sounds at different positions and capturing responses. This periodic measurement approach allows for complete azimuthal coverage to be achieved efficiently through repeated cycles of sound emission and capture at different angular positions, balancing comprehensiveness with time efficiency.
Solution Approach 2:
The system performs preliminary action by collecting HRTF measurement data during the mobile device's movement around the user's head. Rather than requiring separate dedicated measurement sessions, the system gathers spatial audio data as part of the normal interaction, allowing HRTF maps to be generated from measurements taken during routine device usage, thereby reducing additional time requirements.
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 accurate and cost-effective generation of HRTF maps in a user-controlled setting, allowing for realistic spatial audio rendering without the need for laboratory equipment.
Implementation Method 1
a device speaker of the mobile device can emit sounds while the mobile device is moved along an azimuthal path
Implementation Method 2
a headphone microphone can detect directly received sounds and indirectly received sounds to determine an HRTF
Data Source
AI summary
An audio system and a method of using the audio system to generate a head-related transfer function (HRTF) map, are described. The audio system can determine one or more HRTF and corresponding HRTF locations along an azimuthal path of an azimuth extending around a head of a user. The HRTFs or HRTF locations can be measured, and other HRTFs or HRTF locations can be interpolated or extrapolated. The HRTF map can include the HRTFs assigned to HRTF locations along the azimuth. HRTFs from the HRTF map are used to render spatial audio to the user. Other aspects are also described and claimed.