Definition: A three-dimensional (3D) digitizer measures the exact location of specific points on a real-world object and converts this information into a set of 3D points in a coordinate system. It is typically used to record the position of fNIRS optodes on the participant’s head together with reference points or anatomical landmarks. Later this information can be used to obtain MNI coordinates of the optodes or channels by using spatial registration tools.In contrast to non-contacting 3D Scanners, which utilize technologies such as lasers, sound, or magnetism to scan an entire object or area, 3D digitizers are close-distance systems that use a stylus or articulated arm to mark points on an actual object based on an electromagnetic field.
Alternative definition:
Synonym: Digitizer
References: https://doi.org/10.1016/j.neuroimage.2005.05.019, https://doi.org/10.1109/EMBC.2013.6611270
Related terms: spatial registration, 3D Scanner