Method of locating EEG and/or MEG sensors provided with reflective markers on a head of a subject, wherein a plurality of cameras are attached to a structure, such that when their positions are fixed relative to the head, and the head is positioned within a target volume in the structure, each marker is seen by at least three cameras. Synchronized two-dimensional images of the reflective markers are captured and three-dimensional coordinates corresponding to each marker are calculated by triangulation. In the same position, part of the face is digitized using a photogrammetry technique involving projection of a light pattern from a fixed location relative to the cameras. The relative position between the digitized face part and the markers coordinates is resolved. The digitized head surface is matched with the corresponding surface of a 3D MRI image to resolve the locations of the sensors relative to the head.
