Binaural Rendering HRTF Phase Response Optimization
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Solution Overview
Problem
Binaural rendering technologies face challenges in efficiently processing audio signals in mobile devices due to high calculation and power requirements, limited head-related transfer functions (HRTFs), and the comb-filtering effect that degrades sound quality when combining audio signals in virtual reality environments.
Innovation Solution
An audio signal processing device that modifies the phase response of HRTFs to ensure linear phase responses for both ipsilateral and contralateral filters, uses interaural time difference (ITD) information, and interpolates HRTFs to enhance spatial resolution, thereby reducing the comb-filtering effect and preserving timbre.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If binaural rendering is performed using multiple HRTFs corresponding to different positions, then spatial resolution and sound localization accuracy are improved, but the amount of calculation and power consumption increase
Solution Approach 1:
The patent changes the phase response parameter of HRTFs to be position-independent, allowing a single set of HRTFs to be used across all positions. This reduces the number of HRTF sets needed from multiple position-specific sets to just one universal set, significantly reducing calculation load and power consumption while maintaining sound localization accuracy through the preserved magnitude response characteristics
Solution Approach 2:
The patent creates universal HRTFs that can be applied to any sound source position in three-dimensional space, rather than requiring separate HRTF sets for each position. This multi-functional HRTF set serves all positional rendering needs, reducing memory requirements and computational overhead while maintaining accurate spatial audio reproduction
2Reliability
If additional signals are synthesized with binaural rendered audio signals in time domain, then reproducibility is improved, but comb-filtering effect degrades sound quality
Solution Approach 1:
The patent replaces time-domain synthesis with frequency-domain synthesis for combining binaural rendered audio signals with additional signals. This substitution avoids the comb-filtering effect that occurs in time-domain addition by enabling precise control of phase relationships between signals, thereby eliminating the harmful interference patterns while maintaining improved reproducibility
3Measurement precision
If HRTFs are measured for more positions, then spatial resolution is improved, but memory capacity requirements increase
Solution Approach 1:
The patent changes the phase response parameter of HRTFs to be position-independent, allowing a single universal set of HRTFs to replace multiple position-specific HRTF sets. This reduces memory storage requirements from storing multiple complete HRTF sets to storing just one universal set, while maintaining high spatial resolution through the preserved magnitude response characteristics that encode spatial information
Data Source
AI summary
Disclosed is an audio signal processing device including a processor for outputting an output audio signal generated based on an input audio signal. The processor may be configured to obtain a first pair of head-related transfer function (HRTF)s including a first ipsilateral HRTF and a first contralateral HRTF based on a position of a virtual sound source corresponding to the input audio signal, from a first set of transfer functions including HRTFs corresponding to each specific position with respect to listener, and generate the output audio signal by performing binaural rendering the input audio signal based on the first pair of HRTFs.