Crosstalk Cancellation Filter Using Obstructed Field Model
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Solution Overview
Problem
Crosstalk cancellation techniques in sound field control face challenges due to the violation of the free-field assumption by scattering and occlusion effects of the human head, which diminish the quality of binaural localization and virtual auditory environments.
Innovation Solution
The implementation of a crosstalk cancellation filter set that incorporates a pressure matching system and a spherical head model to account for and utilize scattering and occlusion effects, allowing for improved acoustic displays without the need for headphones by using an obstructed field model for spatial filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a free-field assumption is used for crosstalk cancellation, then the system complexity is low, but the binaural localization quality deteriorates due to unaccounted scattering and occlusion effects
Solution Approach 1:
The patent converts the harmful scattering and occlusion effects into beneficial factors by incorporating them into the obstructed field model. The head-related transfer functions (HRTFs) that account for these physical effects are used to improve binaural localization quality, transforming what was previously considered interference into useful information for accurate spatial audio reproduction
Solution Approach 2:
The patent changes the fundamental parameter of the sound field model from free-field assumption to obstructed field model. This parameter change incorporates the scattering and occlusion effects of the human head and body into the crosstalk cancellation system, significantly improving binaural localization quality while maintaining practical system implementation
2Ease of manufacture
If scattering and occlusion effects are ignored, then the crosstalk cancellation system is simpler to implement, but the perception of virtual auditory effects deteriorates
Solution Approach 1:
The physical scattering and occlusion effects that were previously ignored are now intentionally incorporated into the obstructed field model. By using measured or synthesized HRTFs that include these effects, the system achieves more accurate virtual auditory reproduction while maintaining implementation feasibility through standard audio processing techniques
3Measurement precision
If an obstructed field model is implemented to account for head and body effects, then binaural localization quality improves, but the computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-computing or pre-measuring the head-related transfer functions (HRTFs) that account for scattering and occlusion effects. These pre-computed filters are then applied in the crosstalk cancellation system, avoiding the need for real-time complex computations while maintaining high binaural localization quality
Solution Approach 2:
The patent uses copied or measured HRTF data from standardized models (such as the spherical head model) or individual measurements to represent the complex scattering and occlusion effects. This copying approach allows the system to achieve accurate binaural reproduction without requiring complex real-time computational models of individual head geometries
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
This approach enhances the fidelity of the spatial image and virtual auditory environment by canceling out physical head-related transfer functions while maintaining virtual ones, resulting in improved crosstalk cancellation performance and increased ear separation, especially in the low-frequency range.
Implementation Method 1
a pressure matching system configured to perform spatial filtering or sound field control
Implementation Method 2
the free-field assumption is violated by the scattering and occlusion effects of the human head and body
Implementation Method 3
configured a spherical head model for communication with the pressure matching system... taking acoustic advantage of scattering effects and occlusional effects caused by a human head
Data Source
AI summary
A crosstalk cancellation filter set configured for use in delivering binaural signals to human ears is provided. The crosstalk cancellation filter set includes a pressure matching system configured to perform spatial filtering or sound field control and an obstructed field model in communication with the pressure matching system. The crosstalk cancellation filter set is configured to take acoustic advantage of scattering effects and occlusional effects caused by violations to a free-field assumption, thereby delivering improved crosstalk cancellation acoustic displays to a listener without the use of headphones.