University of Twente Student Theses


Target tracking for endoluminal interventions

Voskuilen, L. (2015) Target tracking for endoluminal interventions.

[img] PDF
Abstract:Flexible endoscopy has evolved from a strictly diagnostic modality to technique that also offers simple endoluminal interventions. In the future more complex interventions will be developed, however improvements to the flexible endoscopic platform are needed to facilitate this progression. One very promising improvement is the robotisation of flexible endoscopy. Robotisation also allows other techniques that may improve complex endoluminal interventions, such as target tracking. Target tracking is the use of computer vision software to follow a certain target in an image sequence. The displacement of the target can be returned to the robot to lock onto the target, creating a target lock. We aim to develop an accurate, reliable and real-time target lock. The target tracking algorithm is based on a GPU-accelerated SURF (speeded-up robust features) feature detector and a brute force feature matcher using computer vision library OpenCV. The pre-processing, feature detection and matching, and post-processing were optimised using videos from regular clinical practice. Subsequently, the tracking algorithm is validated using a series of videos of endoluminal interventions recorded at the Meander Medical Center. The location target in the videos has been manually annotated by expert endoscopists providing a ground truth. The target location calculated by the algorithm is compared to this ground truth. Overall the agreement between algorithm and endoscopist was good, but some weaknesses were identified, such as the inaccurate tracking during quick movements. However, the algorithm proved to be resistant to disturbances such as smoke or instruments in the field-of-view, and the throughput was in real-time. Next, the tracking algorithm was validated in a controlled laboratory environment, using a robotic arm to consistently move the target. An optical tracking system was used to track the location and orientation of the target and the endoscope tip and provide a ground truth. The tracking was found to be in real time and very reliable, but improvements may still be made in the accuracy and reducing the latency. Using a controller developed by Frijnts, we were able to achieve a target lock under these controlled circumstances.
Item Type:Essay (Master)
Meander Medisch Centrum
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Programme:Electrical Engineering MSc (60353)
Link to this item:
Export this item as:BibTeX
HTML Citation
Reference Manager


Repository Staff Only: item control page