Image-Guided Control of an Endoscopic Robot for OCT Path Scanning

Optical coherence tomography (OCT) endoscopic catheters provide efficient solutions for the non-invasive scan of malignant tissues in internal human organs. In this letter, we investigate the image-guided control of a robotic flexible endoscopic system equipped with an OCT probe for autonomous tissue scanning. The visual control strategy is achieved by combining the image feedback from both a monocular endoscopic camera (eye-to-hand) and an OCT probe (eye-in-hand). Our control strategy allows the OCT probe to automatically track a trajectory defined by the user on the 2D endoscopic image and keep contact with the scanned surface. The orientation, depth, and endoscopic 2D image position are controlled by solving an optimization problem, which is converted to a quadratic programming problem. For the implementation of the visual control strategy, we also consider visibility constraints and actuators limitations. In addition, a marker-based method to estimate the 3D pose of the continuum robot using only 2D images is proposed based on a Kalman filter and a registration technique. The proposed control strategy is validated using both simulation and laboratory experiments.