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Morphometric Parameters
Clinical Morphometric Presets
Terminal Utilities
Terminal Ready. Hover over ear structures to inspect.

Overview: Advanced Auricular Morphometry & Acoustic Physics

The human pinna (auricle) is a complex cartilaginous outer-ear structure that gathers environmental acoustic wavefronts and focuses them through the external auditory canal. The geometric topology of the auricle—including the helix rim, antihelix crura, triangular fossa, scapha, concha cavum, concha cymba, tragus, and lobule—acts as a continuous spatial filter. By selectively attenuating high frequencies and generating direction-dependent pinna notches ($3\text{ kHz} - 12\text{ kHz}$), the outer ear provides essential psychoacoustic cues for vertical elevation sound localization and front/back disambiguation.

EarDraw Laboratory is an interactive biomedical workspace designed to model anatomical ear variations, realistic dermal phototypes, elastic cartilage skeletons, and dynamic Head-Related Transfer Functions ($\text{HRTF}$). Users can adjust morphometric dimensions, inspect localized anatomical structures in real time, and observe the resulting acoustic notch filtering profiles on an integrated frequency spectrum analyzer.

How to Use the Interactive Laboratory Terminal

  1. Morphometric Parameters: Use the sliders in the sidebar to alter ear length ($L_{ear}$), width ($W_{ear}$), lobule volume ($S_{lobule}$), outer helix curvature ($\kappa_{helix}$), Darwin's tubercle prominence, and lobule attachment mode.
  2. Render Modes & Phototypes: Switch between Realistic Dermal Shading, Anatomical Diagram (color-coded functional regions), and Cartilage Skeleton modes. Adjust dermal melanin phototypes using the Fitzpatrick scale selector.
  3. Interactive Anatomical Hover Inspection: Move your cursor over the visualizer canvas to highlight specific anatomical features (such as the *Fossa Triangularis* or *Concha Cavum*) and inspect their precise clinical terms.
  4. Clinical Presets: Click any preset button (*Standard Adult*, *Stahl's Ear*, *Macrotia*, *Microtia Type I*) to load standardized anthropometric baselines.
  5. Acoustic Spectrum Analyzer: Observe the real-time HRTF acoustic notch graph rendered below the pinna silhouette to see how concha volume changes shift acoustic notch frequencies.

Technical Details, Mathematical Models & Acoustic Equations

The pinna geometry is modeled using chained cubic BĂ©zier curves parameterized by morphometric dimensions:

$$B(t) = (1-t)^3 P_0 + 3(1-t)^2 t P_1 + 3(1-t) t^2 P_2 + t^3 P_3, \quad t \in [0, 1]$$

The primary conchal resonance frequency $f_{res}$ and directional pinna notch frequency $f_{notch}$ are calculated using quarter-wave resonator equations:

$$f_{res} \approx \frac{c}{4 L_{concha}}, \quad f_{notch} \approx \frac{c}{2 D_{concha}}$$

where $c = 343\text{ m/s}$ is the acoustic speed in air, $L_{concha} \approx 0.35 \cdot L_{ear}$, and $D_{concha} \approx 0.22 \cdot W_{ear}$.

Future Directions

  • Integration with 3D boundary element method (BEM) acoustic solvers.
  • STL/OBJ mesh export for custom 3D-printed hearing aid shell manufacturing.
  • Automated ear landmark recognition from webcam feeds using deep neural networks.

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