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Updated: Jun 24, 2026
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Precision Measurements and Parametric Models of Vertebral Endplates
Published on: September 17, 2019
An adaptive and fully automatic method for estimating the 3D position of bendable instruments using endoscopic
Paolo Cabras1, Florent Nageotte1, Philippe Zanne1
1ICube Laboratory, University of Strasbourg, CNRS, 300, Bd. Sèbastian Brant, CS 10413 - F-67412, Illkirch Cedex, France.
Summary
This study presents an automatic method to determine the 3D position of flexible endoscopic instruments using colored markers and a monocular camera. The system accurately tracks instrument movement in real-time, even in challenging lighting conditions.
Area of Science:
- Medical Robotics
- Surgical Endoscopy
- Computer Vision
Background:
- Flexible bendable instruments are essential for surgical endoscopy.
- Accurate 3D position measurement of these instruments is crucial for robotic control and motion analysis.
Purpose of the Study:
- To develop an automatic method for inferring the 3D pose of a single bending section instrument.
- To enable precise tracking using only a monocular camera at the endoscope tip.
Main Methods:
- Utilizes colored markers attached to the instrument's bending section.
- Employs graph-based segmentation and Bézier curve fitting for marker corner extraction.
- An adaptive model accounts for mechanical play for pose estimation.
Main Results:
- Marker corner localization is accurate, even with sensor saturation in vivo.
- Laboratory experiments show root-mean-square errors of 2.1, 1.96, and 3.18 mm in x, y, and z directions.
- Qualitative analysis confirms accurate 3D tip position estimation during real in vivo motions.
Conclusions:
- The proposed method offers automatic and accurate 3D position estimation for bendable instruments.
- This approach succeeds in realistic conditions where standard methods falter.
