Tech spec: fiducial relocalization

Make fiducial relocalization its own module and split RANSAC out of RelocalizationModule; each module owns its gates and publishes world_T_map only after qualifying the fix.

There is no shared judge, and one relocalization module owns world -> map in each blueprint.

dimos/mapping/relocalization/
├── fiducial.py
└── ransac.py

fiducial.py consumes detections from MarkerDetectionStreamModule.

Qualification

Tag sighting qualification

MarkerDetectionStreamModule and fiducial relocalization will share the same marker sighting qualificatoin util code. It gates each ArUco sighting using ambiguity, reprojection error, view angle, range, and tag size, then fuses accepted sightings into a candidate pose. Well researched.

Candidate qualification

The fiducial candidate gate is not decided yet. Possible checks include translational and rotational error and voxel-map matching from lidar or vision; research will choose the checks and thresholds.

RANSAC relocalization

The RANSAC module owns its gates and may need tuning or changes.

Start by reading the existing relocalization implementation and the MarkerDetectionStreamModule, then compare the proposed dimos/mapping/relocalization/fiducial.py and ransac.py split. Research and decide the fiducial candidate checks and thresholds, while preserving shared marker-sighting qualification. Done means each module owns its gates and publishes world_T_map only after qualifying its fix.