Snapback — On-device Vision Prototype (OpenCV + MediaPipe + VLM)

A small prototype that runs a real-time desk camera loop and overlays user state.

• Capture/overlay: OpenCV
• On-device inference: MediaPipe FaceLandmarker (Tasks API)
• Coaching layer (optional): Ollama + qwen2.5vl:3b (VLM)

This repo is used as a concrete “on-device vision pipeline” artifact (capture → inference → overlay → latency measurement).

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What it does

• Grabs webcam frames
• Runs face landmark detection (and derives simple features like EAR)
• Tracks a coarse state (focused/distracted/etc.)
• (Optional) calls a VLM periodically and shows a short coaching message

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Setup

This project uses uv (recommended).

# inside the repo
uv sync

If you don’t use uv, you can still install from pyproject.toml using your preferred tool.

Note: On first run, detector.py downloads face_landmarker.task from the official MediaPipe model bucket.

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Run

uv run python main.py

Press q to quit.

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Benchmark (latency)

Quick end-to-end-ish benchmark for the FaceLandmarker inference step:

uv run python bench_mediapipe.py --frames 200

It prints average / p50 / p95 milliseconds per frame.

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Files

• main.py — OpenCV loop + overlay + glue
• detector.py — MediaPipe FaceLandmarker (Tasks API) + EAR/head signals
• bench_mediapipe.py — simple latency benchmark runner
• vlm_coach.py, vlm.py — VLM layer (Ollama + qwen2.5vl)

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Notes

• This is a prototype. It is OK to describe it as a prototype / exploration on a resume.
• If you need a sharable artifact: add
  • README run steps (already)
  • one screenshot under assets/
  • benchmark output (this repo includes a runner)