title: Motion tracking in narrow spaces: a structured light approach.
abstract: We present a novel tracking system for patient head motion inside 3D medical scanners. Currently, the system is targeted at the Siemens High Resolution Research Tomograph (HRRT) PET scanner. Partial face surfaces are reconstructed using a miniaturized structured light system. The reconstructed 3D point clouds are matched to a reference surface using a robust iterative closest point algorithm. A main challenge is the narrow geometry requiring a compact structured light system and an oblique angle of observation. The system is validated using a mannequin head mounted on a rotary stage. We compare the system to a standard optical motion tracker based on a rigid tracking tool. Our system achieves an angular RMSE of 0.11 degrees demonstrating its relevance for motion compensated 3D scan image reconstructions as well as its competitiveness against the standard optical system with an RMSE of 0.08 degrees. Finally, we demonstrate qualitative result on real face motion estimation.
authors.affiliation: Informatics and Mathematical Modelling, Technical University of Denmark Richard Petersens Plads, Building 321, DK-2800 Kgs. Lyngby, Denmark. ovol@imm.dtu.dk
authors.forename: Oline Vinter
authors.initials: OV
authors.lastname: Olesen
authors.forename: Rasmus R
authors.initials: RR
authors.lastname: Paulsen
authors.forename: Liselotte
authors.initials: L
authors.lastname: Højgaar
authors.forename: Bjarne
authors.initials: B
authors.lastname: Roed
authors.forename: Rasmus
authors.initials: R
authors.lastname: Larsen
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006257:Head / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008027:Light; D010363:Pattern Recognition, Automated / Q000379:methods*; D010783:Photometry / Q000295:instrumentation*; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D012542:Scattering, Radiation