Research Area 3 · Computer Vision · Spatial Awareness · Classroom Safety

Multi-Camera Spatial Perception & Distance Estimation

Two Logitech BRIO 4K cameras, mounted on opposite sides of the room.

Individual research by Sonika Dhenuva Konda

People and equipment constantly move around a busy classroom. A standard camera can see what's in the room, but not how far away it is or where it sits in 3D. Two wide-spaced cameras, fused with depth models and geometry, can fix that.

How can a setup of two wide-spaced 4K cameras combine separate 2D video feeds using deep learning models and geometry to accurately measure real-world distances and build a continuous 3D spatial map of a classroom?

flowchart TD
    C1["Camera 1, BRIO
Wall A"] --> FM["SuperPoint + LightGlue
Cross-view matching"]
    C2["Camera 2, BRIO
Wall B"] --> FM
    C1 --> DA["Depth Anything V2
Per-frame depth map"]
    C2 --> DA
    FM --> GEO["OpenCV + NumPy
Calibration + 3D projection"]
    DA --> GEO
    GEO --> SCALE["ZoeDepth
Metric scale, m / ft"]
    SCALE --> CLOUD["Open3D
Point cloud / room map"]
    C1 --> YOLO["YOLOv8
Object boxes"]
    C2 --> YOLO
    YOLO --> CLOUD
2× Logitech BRIO 4K

USB 3.0, opposite walls, facing inward.

OpenCV

Calibration, distortion fix, 3D projection.

PyTorch

Runs the deep learning models on GPU.

NumPy

Linear algebra for coordinate rotation.

Open3D

Renders the room as a point cloud.

Depth Anything V2

Dense depth map from a single frame.

SuperPoint + LightGlue

Keypoints matched across wide baselines.

YOLOv8

Boxes people/objects before distancing.

Stereo Vision (chosen)

Cheap, standard RGB webcams; needs calibration + good light.

dToF / LiDAR

Very accurate; too costly, hurt by sunlight.

Indirect ToF

Fast full-frame depth; whiteboards cause interference.

Structured Light

Great up close; range drops off past 3–5m.

Depth Anything V2 Yang et al. · arXiv:2406.09414
  • Foundation model for single-image (monocular) depth estimation.
  • Trained on millions of synthetic and pseudo-labeled images.
  • Generates a dense depth map from just one frame.
  • Fills in depth on plain classroom walls where matching alone fails.
LightGlue: Local Feature Matching at Light Speed Lindenberger et al. · ICCV 2023 · arXiv:2306.13643
  • Neural network that matches keypoints between two images.
  • Faster and more accurate than its predecessor, SuperGlue.
  • Adaptive: less compute on easy pairs, more on hard ones.
  • Built for exactly this project's wide-baseline, opposite-wall pair.
ZoeDepth: Combining Relative and Metric Depth Bhat et al. · arXiv:2302.12288
  • Adds a metric prediction head onto a relative-depth model.
  • Outputs real distances in meters, not just relative ordering.
  • Zero-shot transfer across different scenes.
  • Used here to scale outputs into real classroom feet/meters.
3-D Depth Reconstruction from a Single Still Image Saxena, Chung & Ng · IJCV
  • Early work using single-image cues: shading, texture, perspective lines.
  • Combines those cues with multi-camera stereo geometry.
  • Shows the combination beats either method alone.
  • Basis for pairing an AI depth model with physical camera geometry here.
Multi-Camera Collaborative Depth Prediction via Consistent Structure Estimation Xu et al. · arXiv:2210.02009
  • Multiple overlapping cameras share depth information.
  • Depth built as a weighted combination of a shared "depth basis."
  • Works even without large overlap between camera views.
  • Blueprint for merging the two BRIO feeds into one coordinate space.
Non-rigid Stereo Vision Camera System US Patent 11,321,876 B2 · PCT/US2021/12294
  • Stereo vision that keeps working when cameras aren't on a rigid mount.
  • Autocalibration corrects fast (vibration) and slow (thermal) shifts over time.
  • Supports wide baselines, over 2 meters apart.
  • Directly applies since the two BRIOs sit on opposite walls, not a fixed bar.
e-con Systems: Depth Perception & 3D Imaging e-con Systems Technology Blog
  • Compares active sensors (LiDAR, ToF) against passive vision (stereo).
  • Background for the depth-sensing comparison above.
OpenCV Camera Calibration Docs OpenCV Official Documentation
  • Reference for cv2.calibrateCamera() and lens-distortion correction.
  • Basis for the calibration step in the pipeline diagram.