> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cyberwave.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Camera Detection Overlays

> Draw YOLO bounding boxes from an ML worker onto the camera driver's WebRTC stream.

<Warning>
  **STUB DOCUMENT:** This page is intentionally minimal and will be expanded with deeper technical details in a future update.
</Warning>

The generic `cyberwave-edge-camera-driver` subscribes to detection results published by any ML worker on the same Zenoh router and renders bounding boxes + labels on the WebRTC stream before it reaches the frontend. No client-side changes are required.

## How it works

* Frames captured from the camera are published **clean** on `cw/<twin_uuid>/data/frames/<sensor>` — ML workers always receive unannotated images.
* The driver also subscribes to `cw/<twin_uuid>/data/detections/**`. Any worker that publishes detections on that channel (e.g. `detections/ultralytics`, `detections/onnxruntime`) drives the overlay.
* Bounding boxes are drawn in-place on the capture ndarray before it is handed to the WebRTC encoder, so the browser sees annotated frames without any extra infrastructure.
* Workers publish every inference — including empty `{"detections": []}` heartbeats — so the driver's freshness timer is kept alive between non-empty frames. Batches older than 2 seconds are discarded to avoid stale overlays.

## Detection payload schema

```json theme={null}
{
  "detections": [
    {"label": "person", "confidence": 0.92, "x1": 120, "y1": 80, "x2": 340, "y2": 620}
  ],
  "frame_width": 1920,
  "frame_height": 1080
}
```

Coordinates are in pixel space of the detection frame. The driver rescales them to the capture resolution.

## Configuration

| Variable                       | Default | Description                                        |
| ------------------------------ | ------- | -------------------------------------------------- |
| `CYBERWAVE_DETECTION_OVERLAYS` | `true`  | Set to `false` to disable overlays on RGB cameras. |

Overlays are disabled automatically for twins that declare a depth sensor in their capabilities.

## Interop with native drivers

The same channel, payload schema, and staleness policy are used by the C++ OBSBOT driver, so an ML worker only needs to publish once — both driver families render the results identically.