mikkeli
0f423fccd6
- capture.py: detect faces with haar cascades (cv2.CascadeClassifier), draw green rectangles on frames before streaming - capture/haarcascades/: bundled haar cascade XML - README.md: document face detection feature and opencv dependency
86 lines
2.6 KiB
Markdown
86 lines
2.6 KiB
Markdown
# usb-camera-webui
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Live MJPEG video feed from a USB webcam, served through a minimal web UI, running on a
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Raspberry Pi 5.
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## Quick start
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```bash
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# Install dependencies
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sudo apt install -y python3-opencv python3-v4l2
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# Run directly
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python3 -m camera.app --host 0.0.0.0 --port 8080
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```
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Open http://localhost:8080 in a browser. Faces visible in the camera view are marked
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with green rectangles.
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## Systemd service
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The app runs natively on the Pi via a systemd unit.
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### Install
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```bash
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# Install dependencies
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sudo apt install -y python3-opencv python3-v4l2
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# Copy the service unit
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sudo cp camera-webui.service /etc/systemd/system/
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sudo systemctl daemon-reload
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sudo systemctl enable --now camera-webui
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```
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### Check status
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```bash
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sudo systemctl status camera-webui
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journalctl -u camera-webui --follow
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```
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### Uninstall
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```bash
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sudo systemctl disable --now camera-webui
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sudo rm /etc/systemd/system/camera-webui.service
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sudo systemctl daemon-reload
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```
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## Architecture
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```
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┌──────────────┐ ┌──────────────┐ ┌──────────┐
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│ V4L2 mmap │───▶│ capture.py │───▶│ MJPEG │
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│ (V4L2 API) │ │ + face det. │ │ server │
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└──────────────┘ └──────────────┘ │ :8080 │
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└──────────┘
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│
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┌─────▼─────┐
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│ Browser │
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│ (MJPEG img)│
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└───────────┘
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```
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- **`capture.py`** opens `/dev/video0` via V4L2 mmap buffers, dequeues MJPEG frames in a
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background thread, runs face detection (haar cascades, downscaled for speed), draws
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green rectangles, and stores the processed frame.
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- **`mjpeg.py`** serves the MJPEG stream (`multipart/x-mixed-replace`) via Python's
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built-in `http.server` with threading. Only new frames are sent.
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- **`app.py`** is the entry point: argument parsing, signal handling, and server launch.
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## Hardware
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| Item | Details |
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|---|---|
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| Camera | Logitech C505 HD Webcam (`046d:08e3`) |
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| Device | `/dev/video0` (USB/UVC) |
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| Format | MJPEG 1280×720 |
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| Board | Raspberry Pi 5, Debian 12 (bookworm) |
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## Dependencies
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- `python3-opencv` — OpenCV for face detection (haar cascades, JPEG encode/decode)
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- `python3-v4l2` — V4L2 Python bindings for camera access
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- No pip packages needed
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