title: An adaptive 6-DOF tracking method by hybrid sensing for ultrasonic endoscopes.
abstract: In this paper, a novel hybrid sensing method for tracking an ultrasonic endoscope within the gastrointestinal (GI) track is presented, and the prototype of the tracking system is also developed. We implement 6-DOF localization by sensing integration and information fusion. On the hardware level, a tri-axis gyroscope and accelerometer, and a magnetic angular rate and gravity (MARG) sensor array are attached at the end of endoscopes, and three symmetric cylindrical coils are placed around patients' abdomens. On the algorithm level, an adaptive fast quaternion convergence (AFQC) algorithm is introduced to determine the orientation by fusing inertial/magnetic measurements, in which the effects of magnetic disturbance and acceleration are estimated to gain an adaptive convergence output. A simplified electro-magnetic tracking (SEMT) algorithm for dimensional position is also implemented, which can easily integrate the AFQC's results and magnetic measurements. Subsequently, the average position error is under 0.3 cm by reasonable setting, and the average orientation error is 1° without noise. If magnetic disturbance or acceleration exists, the average orientation error can be controlled to less than 3.5°.
authors.affiliation: Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. dcy_tju@126.com.
authors.forename: Chengyang
authors.initials: C
authors.lastname: Du
authors.affiliation: Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. xdchen@tju.edu.cn.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. koala_wy@tju.edu.cn.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. cd_ljw@126.com.
authors.forename: Junwei
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Opto-Electronics Information Technology of Ministry of Education, College of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China. dyyu@tju.edu.cn.
authors.forename: Daoyin
authors.initials: D
authors.lastname: Yu
mesh_terms: D000465:Algorithms; D019723:Endoscopes; D019160:Endosonography / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D007091:Image Processing, Computer-Assisted / Q000379:methods*