Fiducial Marker

Definition: Fiducials are usually referred to as physical attachments, insertions, or digital markers, often positioned at well-defined locations with strong detectable signals in the acquired experimental data or auxiliary measurements. Fiducials are typically used for facilitating the localization of sensors and co-registration between probes and anatomical structures.

Alternative definition:

Synonym: Fiducial landmark, Fiducial

References: https://bids-specification.readthedocs.io/en/stable/04-modality-specific-files/11-near-infrared-spectroscopy.html

Related terms: Coordinate system, Vitamin E capsules, Digitizer