Binaural Headphone Rendering with Gyro-Based Head Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing audio signal enhancement systems for headphones introduce unwanted artifacts such as coloration, resonance, and distortion when reproducing surround sound or stereo recordings, leading to an unnatural listening experience.
Innovation Solution
A method and system that utilize a digital gyroscope to track head rotational angles and update binaural rendering filters, including shelving, notch, and inter-aural time delay filters, to simulate a desired sound system without these artifacts, using a database of head-related transfer functions to transform audio signals for improved spatial hearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If stereo or surround sound recordings are reproduced over headphones using conventional enhancement systems, then the listening experience is enhanced, but unwanted artifacts such as coloration, resonance, reverberation, and distortion of timbre or sound source angle and position are introduced
Solution Approach 1:
The system dynamically adjusts the binaural rendering filter parameters based on real-time head tracking data from the digital gyroscope. As the user moves their head, the filter parameters are updated to maintain accurate sound source localization and prevent front-back confusion, thereby enhancing sound reproduction quality without introducing artifacts
Solution Approach 2:
The system changes the parameters of the binaural rendering filter (such as inter-aural time delay, level differences, and spectral shaping) based on head orientation detected by the digital gyroscope. This dynamic parameter adjustment allows the system to reproduce sound accurately for different head positions while avoiding the fixed-parameter artifacts that plague conventional systems
2Measurement precision
If head tracking is implemented using a digital gyroscope, then sound source localization stability during head movements is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical head tracking mechanisms with a digital gyroscope, which uses microelectromechanical systems (MEMS) technology. This substitution provides precise measurement of head rotational angles while significantly reducing mechanical complexity, making the system more compact and reliable
Solution Approach 2:
The digital gyroscope automatically detects head movements and provides rotational angle data without requiring manual input or calibration from the user. The system self-adjusts the audio rendering based on the detected head orientation, eliminating the need for complex user interfaces or manual setup procedures
3Reliability
If binaural rendering filters are updated in real-time based on head rotational angle, then front-back confusion is eliminated, but processing time and computational load increase
Solution Approach 1:
The system pre-calculates and stores binaural rendering filter parameters for various head orientations in lookup tables. When the digital gyroscope detects a head rotation, the system quickly retrieves the appropriate pre-computed parameters rather than calculating them in real-time, significantly reducing processing time while maintaining accurate sound localization
Solution Approach 2:
The system updates only the necessary filter parameters that are affected by head rotation, rather than recalculating the entire binaural rendering chain. This selective updating approach reduces computational load and processing time while still eliminating front-back confusion and maintaining localization accuracy
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 system provides a natural and immersive three-dimensional audio experience by maintaining stereo or surround sound enhancements while eliminating 'front-back confusion and unwanted artifacts, allowing sound localization to remain stable during head movements.
Implementation Method 1
receiving an angular velocity signal from a digital gyroscope mounted to a headphone assembly
Implementation Method 2
transforming the audio input signal to an audio output signal using the at least one binaural rendering filter... using a database of head-related transfer functions
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A sound enhancement system (SES) that can enhance reproduction of sound emitted by headphones and other sound systems is disclosed. The SES improves sound reproduction by simulating a desired sound system without including unwanted artifacts typically associated with simulations of sound systems. The SES facilitates such improvements by transforming sound system outputs through a set of one or more binaural rendering filters derived from direct and indirect head-related transfer functions (HRTFs). Parameters of the binaural rendering filters are updated based on the head tracking angle of user wearing the headphones to render a stable stereo sound image. The head tracking angle may be determined from sensor data obtained from a digital gyroscope mounted in a headphone assembly.