Audio Processing Device Annular Harmonic HRTF Synthesis
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Solution Overview
Problem
Current ambisonics systems require a large speaker array for effective sound reproduction, which is impractical for home use and limits the spatial resolution and 'sweet spot' for listeners, especially in environments like movie theaters.
Innovation Solution
Combining ambisonics with binaural reproduction techniques using head-related transfer functions (HRTFs) and performing HRTF synthesis and inverse transformation in the annular harmonic domain to generate headphone driving signals, reducing the number of required speakers and improving sound reproduction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large speaker array is used to improve spatial resolution and sound reproduction quality, then the sound reproduction fidelity is improved, but the device complexity and cost increase significantly making it impractical for home use
Solution Approach 1:
The patent replaces the mechanical speaker array system with a computational audio processing system. Instead of using multiple physical speakers to achieve spatial resolution, the invention uses signal processing techniques (ambisonics decoding, HRTF convolution, binaural rendering) to create virtual spatial audio through headphones, substituting mechanical complexity with computational processing
Solution Approach 2:
The patent creates a virtual copy of the spatial audio experience through computational methods. By using ambisonics decoding and binaural rendering algorithms, the system reproduces the effect of a large speaker array through headphone drivers, creating a virtual acoustic environment without requiring physical replication of multiple speakers
2Area of stationary object
If a large speaker array is used to expand the sweet spot area, then the listening area is improved, but the device complexity and space requirements increase making it unrealistic for home environments
Solution Approach 1:
The patent substitutes the mechanical speaker array with a computational system that uses head-related transfer functions (HRTFs) to track and adapt to head movements. This allows the sweet spot to be effectively expanded to match head movements through real-time processing, rather than requiring a large physical speaker configuration
Solution Approach 2:
The patent introduces dynamic adaptation through head tracking. The audio processing system adjusts the binaural rendering in real-time based on detected head movements, allowing the sweet spot to dynamically follow the listener's head position. This creates an effectively unlimited listening area without requiring additional physical speakers
3Device complexity
If conventional ambisonics combined with binaural reproduction is used to reduce the number of speakers, then the device complexity is reduced, but the computational operation amount and memory usage increase significantly
Solution Approach 1:
The patent performs preliminary computation by pre-calculating and storing ambisonics decoding matrices and HRTF data. By preparing these computational resources in advance and organizing them efficiently in memory, the system reduces the real-time computational burden during actual audio reproduction, trading off initial processing time for faster runtime performance
Solution Approach 2:
The patent optimizes computational parameters by selecting appropriate ambisonics orders and frequency resolutions based on the specific application requirements. By adjusting these parameters, the system balances audio quality with computational load, reducing unnecessary calculations while maintaining essential spatial audio effects
Data Source
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AI summary
The present technology relates to an audio processing apparatus, a method, and a program that aim at enabling a sound to be reproduced more efficiently. A head-related transfer function synthesis section previously holds a matrix of a diagonalized head-related transfer function. The head-related transfer function synthesis section synthesizes an input signal in an annular harmonic domain for reproducing a sound and the previously held and diagonalized head-related transfer function. An annular harmonic inverse transformation section performs an annular harmonic inverse transformation on a signal obtained as a result of the synthesis by the head-related transfer function synthesis section on the basis of an annular harmonic function and thereby generates a headphone driving signal in a time frequency domain. The present technology is applicable to an audio processing apparatus.