Rob Reilink1, Stefano Stramigioli, Sarthak Misra. 1. MIRA-Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands. r.reilink@utwente.nl
Abstract
PURPOSE: Endoscopic images can be used to allow accurate flexible endoscopic instrument control. This can be implemented using a pose estimation algorithm, which estimates the actual instrument pose from the endoscopic images. METHODS: In this paper, two pose estimation algorithms are compared: a marker-less and a marker-based method. The marker-based method uses the positions of three markers in the endoscopic image to update the state of a kinematic model of the endoscopic instrument. The marker-less method works similarly, but uses the positions of three feature points instead of the positions of markers. The algorithms are evaluated inside a colon model. The endoscopic instrument is manually operated, while an X-ray imager is used to obtain a ground-truth reference position. RESULTS: The marker-less method achieves an RMS error of 1.5, 1.6, and 1.8 mm in the horizontal, vertical, and away-from-camera directions, respectively. The marker-based method achieves an RMS error of 1.1, 1.7, and 1.5 mm in the horizontal, vertical, and away-from-camera directions, respectively. The differences between the two methods are not found to be statistically significant. CONCLUSIONS: The proposed algorithms are suitable to realize accurate robotic control of flexible endoscopic instruments, enabling the physician to perform advanced procedures in an intuitive way.
PURPOSE: Endoscopic images can be used to allow accurate flexible endoscopic instrument control. This can be implemented using a pose estimation algorithm, which estimates the actual instrument pose from the endoscopic images. METHODS: In this paper, two pose estimation algorithms are compared: a marker-less and a marker-based method. The marker-based method uses the positions of three markers in the endoscopic image to update the state of a kinematic model of the endoscopic instrument. The marker-less method works similarly, but uses the positions of three feature points instead of the positions of markers. The algorithms are evaluated inside a colon model. The endoscopic instrument is manually operated, while an X-ray imager is used to obtain a ground-truth reference position. RESULTS: The marker-less method achieves an RMS error of 1.5, 1.6, and 1.8 mm in the horizontal, vertical, and away-from-camera directions, respectively. The marker-based method achieves an RMS error of 1.1, 1.7, and 1.5 mm in the horizontal, vertical, and away-from-camera directions, respectively. The differences between the two methods are not found to be statistically significant. CONCLUSIONS: The proposed algorithms are suitable to realize accurate robotic control of flexible endoscopic instruments, enabling the physician to perform advanced procedures in an intuitive way.
Authors: Anthony N Kalloo; Vikesh K Singh; Sanjay B Jagannath; Hideaki Niiyama; Susan L Hill; Cheryl A Vaughn; Carolyn A Magee; Sergey V Kantsevoy Journal: Gastrointest Endosc Date: 2004-07 Impact factor: 9.427