Multi-Camera Detection Routing

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

When a single edge worker runs detection models on frames from multiple cameras (each represented by a different digital twin), detection results must be published back to the correct twin’s Zenoh channel.

The problem

By default, DataBus publishes to the twin it was constructed with. In a multi-camera worker, all detections would land on a single twin’s channel regardless of which camera produced the frame.

Solution: `twin_uuid` routing

Pass twin_uuid=ctx.twin_uuid to model.predict() to route detections to the originating twin.

CAMERA_LEFT = os.environ["CAMERA_LEFT_TWIN"]
CAMERA_RIGHT = os.environ["CAMERA_RIGHT_TWIN"]

model = cw.models.load("yolov8n")

@cw.on_frame(CAMERA_LEFT)
def on_left_frame(frame, ctx):
    model.predict(frame, confidence=0.5, twin_uuid=ctx.twin_uuid)

@cw.on_frame(CAMERA_RIGHT)
def on_right_frame(frame, ctx):
    model.predict(frame, confidence=0.5, twin_uuid=ctx.twin_uuid)

Each hook’s ctx.twin_uuid is set from the decorator registration, so model.predict() publishes detections to cw/{twin_uuid}/data/detections/{runtime} for the correct twin. ctx.sensor_name is populated from the observed Zenoh key (e.g. color_camera), so a single handler can disambiguate multi-sensor twins at runtime.

Omitting sensor= subscribes to the twin’s frames/** wildcard, matching any camera the driver actually publishes. Pin sensor="<name>" only when you need to target one specific sensor on a multi-camera twin (the name must match the twin asset’s sensor id — typically color_camera, depth_camera, etc.).

Cross-twin synchronized hooks

For stereo vision or cross-camera fusion, use @cw.on_synchronized with twin_channels to synchronize frames from different twins:

@cw.on_synchronized(
    twin_channels={
        "left": (CAMERA_LEFT, "frames/default"),
        "right": (CAMERA_RIGHT, "frames/default"),
    },
    tolerance_ms=50.0,
)
def on_stereo_pair(samples, ctx):
    left_frame = samples["left"]
    right_frame = samples["right"]
    # ctx.metadata["twin_uuids"] contains the sorted list of involved twins

The single-twin @cw.on_synchronized(twin_uuid, channels) API continues to work unchanged.

Key API additions

API	Change
`model.predict(..., twin_uuid=)`	Route detections to a specific twin
`DataBus.publish(..., twin_uuid=)`	Override the default twin for a publish
`DataBus.publish_raw(..., twin_uuid=)`	Override the default twin for raw publish
`@cw.on_synchronized(twin_channels=)`	Cross-twin synchronized hook mode

Concepts

Platform Features

Cyberwave Edge

Technical Reference

Use-Case Recipes

Multi-Camera Detection Routing

The problem

Solution: `twin_uuid` routing

Cross-twin synchronized hooks

Key API additions

​The problem

​Solution: twin_uuid routing

​Cross-twin synchronized hooks

​Key API additions

The problem

Solution: `twin_uuid` routing

Cross-twin synchronized hooks

Key API additions