Binaural Audio Reproduction with Head-Rotation HRTF Updates
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Solution Overview
Problem
Conventional spatial sound reproduction methods using binaural rendering and head-related transfer functions (HRTFs) fail to accurately position auditory objects in desired directions and distances, leading to internalization of sound sources and lack of externalization, especially when listeners rotate their heads, due to limitations in reproducing direct-to-reverberant ratios and causing unwanted reverberation and interpolation artifacts.
Innovation Solution
A system employing a static decorrelator engine with multiple static decorrelators and direction-dependent gains, combined with a binaural rendering engine, dynamically updates HRTFs based on head rotation to create inter-aural level differences (ILD) without adding reverberation, allowing for precise control of auditory object placement in space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional binaural rendering with HRTFs is used, then spatial sound reproduction is achieved, but sound sources become internalized and lack externalization when listeners rotate their heads
Solution Approach 1:
The patent applies dynamics by making the HRTF selection adaptive to head rotation. Instead of using fixed HRTFs, the system dynamically selects and interpolates between different HRTF pairs based on detected head orientation, allowing the auditory reproduction to remain accurate and externalized during head movements.
Solution Approach 2:
The patent changes the parameter of HRTF selection based on head rotation angle. By detecting head orientation and selecting appropriate HRTF pairs from a database, the system adjusts the acoustic parameters to maintain proper externalization and spatial positioning across different head positions.
2Reliability
If HRTFs are updated dynamically based on head rotation, then externalization is improved, but interpolation artifacts occur
Solution Approach 1:
The system dynamically selects HRTF pairs based on head rotation angles that are multiples of a predetermined interval. By discretizing the head rotation angles and selecting from predefined HRTF pairs rather than continuously interpolating, the method maintains externalization while avoiding interpolation artifacts.
3Measurement precision
If multiple HRTF pairs are used for different head positions, then accuracy during head movement is improved, but computational complexity increases
Solution Approach 1:
The system uses a predetermined number of HRTF pairs corresponding to discrete head rotation angles. This dynamic selection from a limited set of pre-computed HRTFs maintains positioning accuracy during head movement while avoiding the computational burden of continuous HRTF interpolation or processing of excessive HRTF data.
Data Source
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AI summary
A method including providing an input audio signal in a first path and applying an interpolated head-related transfer function (HRTF)pair based upon a direction to generate direction dependent first left and right signals in the first path; providing the input audio signal in a second path, where the second path includes a plurality of filters and a respective amplifier for each filter, where the amplifiers are configured to be adjusted based upon the direction, and applying to an output from each of the filters a respective head-related transfer function (HRTF)pair to generate direction dependent second left and right signals for each filter in the second path; and combining the generated left signals to form a left output signal for a sound reproduction,and combining the generated right signals to form a right output signal for the sound reproduction.