title: Single-camera motion measurement and monitoring for magnetic resonance applications.
abstract: An optically based rigid-body six-degrees of freedom (DOF) measurement system optimized for prospective (real-time) motion correction in magnetic resonance imaging (MRI) applications is described. By optimizing system capabilities to the specific applications requirements, the six-DOF measurement is accomplished using a single camera and simple three-disc fiducial at rates of 50 Hz. The algorithm utilizes successive approximation to solve the three point pose problem for angles close to the origin. Convergence to submicroradian levels occurs within 20 iterations for angles in an approximate half-radian (29°) arc centered on the origin. The overall absolute accuracy of the instrument is 10-100 μm for translational and <100 μrad (0.005°) for rotational motions. Results for head nodding and speech tasks are presented for subjects in the MR scanner, and the instrument results are compared to standard prospective acquisition correction.
authors.affiliation: Department of Electrical Engineering, The Erik Jonsson School of Engineering and Computer Science, The University of Texas at Dallas, Richardson, 75080-3021, USA. crwildey@gmail.com
authors.forename: Chester
authors.initials: C
authors.lastname: Wildey
authors.forename: Duncan L
authors.initials: DL
authors.lastname: MacFarlane
authors.forename: Aman
authors.initials: A
authors.lastname: Goyal
authors.forename: Kaundinya
authors.initials: K
authors.lastname: Gopinath
authors.forename: Sergey
authors.initials: S
authors.lastname: Cheshkov
authors.forename: Richard
authors.initials: R
authors.lastname: Briggs
mesh_terms: D000465:Algorithms; D019416:Head Movements; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009038:Motion; D055095:Optics and Photonics / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*