Acoustic Head Model Using Ray-Tracing and Near-Field Compensation
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Solution Overview
Problem
Conventional methods for modeling the acoustic effects of the human head are inadequate in accurately predicting interaural time differences (ITD) and interaural level differences (ILD) due to simplifications in head shape and size, leading to discrepancies between measured and modeled data, especially at low frequencies and near-field regions.
Innovation Solution
A novel method involving a high-frequency head model based on ray-tracing and half-plane sections, coupled with a far-field shadowing filter and a near-field compensation filter, which modifies the aspect ratio to create variable geometric models that better approximate anthropomorphic head dimensions and account for acoustic changes between far-field and near-field regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional head models use simplified spherical or ellipsoidal shapes, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision of ITD and ILD deteriorates, especially at low frequencies and near-field regions
Solution Approach 1:
The head model is segmented into multiple half-plane sections that can be independently configured with different dimensions and orientations. This segmentation allows the model to capture complex head geometries and acoustic shadowing effects while maintaining computational tractability through modular construction.
Solution Approach 2:
The model uses configurable parameters including aspect ratio, width, and half-plane section dimensions that can be adjusted to match specific anthropometric measurements. This parameter-based approach enables accurate representation of individual head geometries without requiring complex mesh generation or finite element analysis.
2Device complexity
If a single far-field shadowing filter is used, then the device complexity is minimized, but the measurement precision deteriorates because acoustic changes between far-field and near-field regions are not compensated
Solution Approach 1:
The acoustic compensation is segmented into two distinct filter components: a far-field shadowing filter for distant sources and a near-field compensation filter for close sources. This segmentation allows each filter to be optimized for its specific operational regime while maintaining overall system simplicity through modular filter design.
Solution Approach 2:
The filter system dynamically adapts its behavior based on the sound source distance. The near-field compensation filter is selectively applied when sources are in the near-field region, while the far-field shadowing filter dominates for distant sources. This dynamic adaptation enables accurate acoustic prediction across the full range of source distances without requiring a completely different filter structure.
3Device complexity
If fixed head model geometry is used, then the device complexity is reduced, but the adaptability to different head morphologies and anthropometric dimensions deteriorates
Solution Approach 1:
The head model geometry is defined by configurable parameters including aspect ratio, width, and half-plane section dimensions that can be adjusted to match specific anthropometric measurements. This parameter-based approach enables accurate representation of individual head geometries without requiring complex mesh generation or finite element analysis.
Solution Approach 2:
The half-plane section configuration provides a universal modeling framework that can represent various head shapes and sizes through parameter adjustment. The same basic model structure can be adapted to different anthropometric groups and individual measurements, making the model universally applicable across diverse populations.
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 provides more accurate predictions of ITD and ILD across various frequencies and source positions, improving consistency with acoustic measurements and allowing for a more realistic modeling of the human head's acoustic effects, including low-frequency phase characteristics and near-field shadowing behavior.
Implementation Method 1
forming a high-frequency head model based on ray-tracing and a plurality of half-plane sections
Implementation Method 2
coupling the high-frequency head model with a far-field shadowing filter
Implementation Method 3
coupling the far-field shadowing filter with a near-field compensation filter to compensate for acoustic changes between the far-field and near-field regions
Data Source
AI summary
A method of modeling the human head is provided. The human head model has a width and an aspect ratio. The aspect ratio defines different head shapes independent of the size of the human head model. The method includes the steps of forming a high-frequency head model based on ray-tracing and a plurality of half plane sections, coupling the high-frequency head model with a far-field shadowing filter, coupling the far-field shadowing filter with a near-field compensation filter to compensate for acoustic changes between the far-field and near-field regions and modifying the aspect ratio of the human head model to configure variable geometric models of the human head ranging from a nearly spherical to a very narrow embodiment.