title: A single camera photogrammetry system for multi-angle fast localization of EEG electrodes.
abstract: Photogrammetry has become an effective method for the determination of electroencephalography (EEG) electrode positions in three dimensions (3D). Capturing multi-angle images of the electrodes on the head is a fundamental objective in the design of photogrammetry system for EEG localization. Methods in previous studies are all based on the use of either a rotating camera or multiple cameras, which are time-consuming or not cost-effective. This study aims to present a novel photogrammetry system that can realize simultaneous acquisition of multi-angle head images in a single camera position. Aligning two planar mirrors with the angle of 51.4°, seven views of the head with 25 electrodes are captured simultaneously by the digital camera placed in front of them. A complete set of algorithms for electrode recognition, matching, and 3D reconstruction is developed. It is found that the elapsed time of the whole localization procedure is about 3 min, and camera calibration computation takes about 1 min, after the measurement of calibration points. The positioning accuracy with the maximum error of 1.19 mm is acceptable. Experimental results demonstrate that the proposed system provides a fast and cost-effective method for the EEG positioning.
authors.affiliation: Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Shuo
authors.initials: S
authors.lastname: Qian
authors.forename: Yang
authors.initials: Y
authors.lastname: Sheng
mesh_terms: D000465:Algorithms; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods; D002138:Calibration; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D010780:Photogrammetry / Q000295:instrumentation* / Q000379:methods