LuminaBone — Low-Cost Shading-Based 3D Bone Endoscope
A medical imaging project developing a 6 mm endoscope that uses near-light photometric stereo to reconstruct accurate 3D bone topography in real time — without dye or expensive stereo cameras. Designed for orthopedic and ENT surgical applications.
The Problem
Surgeons working through endoscopes in orthopedic and ENT procedures see a flat, 2D view of curved bone surfaces. Judging depth — how much bone has been removed, how a drill path is progressing, where a ridge ends — relies on experience and indirect cues. Existing 3D solutions either require fluorescent dye, structured-light projectors, or stereo camera pairs that are too bulky and expensive to fit inside a millimeter-scale endoscope.
The goal of LuminaBone is real-time, quantitative 3D bone topography from a single small camera and cheap LEDs — hardware simple enough to fit in a 6 mm endoscope tip and cheap enough to be disposable.
The Approach
LuminaBone uses near-light photometric stereo: instead of multiple cameras, it uses multiple lights. Two off-axis micro-LEDs at the endoscope tip are driven sequentially via PWM, so the camera captures alternating frames lit from different directions. The shading gradients across the rigid bone surface encode its local slope.
- Two off-axis micro-LEDs fire in sequence, synchronized to the camera frame clock via PWM.
- Each frame pair captures shading gradients across the bone surface from two known light positions.
- A Lambertian reflectance model, corrected for inverse-square near-light falloff, solves per-pixel surface normals.
- Normals are integrated into a continuous 3D height map of the bone surface, updated in real time.
- No dye, no structured light, no stereo cameras — just timing, optics, and math.
Technical Details
| Form factor | 6 mm outer-diameter endoscope tip |
| Illumination | 2× off-axis micro-LEDs, sequentially PWM-driven, frame-synchronized |
| Reconstruction | Near-light photometric stereo: Lambertian model + inverse-square falloff correction |
| Pipeline | Per-pixel surface-normal solve → normal-field integration → 3D height map |
| Performance target | ≥ 15 fps real-time reconstruction |
| Validation | Bone phantoms, ground-truthed against high-precision laser scans |
| Applications | Orthopedic & ENT surgery — depth feedback during bone removal and drilling |
Tech & Tools
Timeline
Resources
The internship report and technical write-up will be posted here as the project matures.