Partitioned camera-OCT based 6 DOF visual servoing for automatic repetitive optical biopsies

This paper addresses the design of a partitioned vision-guided scheme for repetitive optical biopsies. More precisely, our approach uses two image modalities to perform 6 degrees of freedom (DOF) positioning task. The development aims to partition the control into 3 DOF controlled by the B-scan images acquired with an optical coherence tomography (OCT) system and the remaining 3 DOF controlled by the white light images provided by a CCD camera. Moreover, for the control and instead of conventional visual features (e.g., points, lines, moments, etc.) extracted using algorithms combined with visual tracking approaches, our visual servoing method uses the multiresolution wavelet coefficients. The developed method was experimentally validated using a parallel kinematic structure equipped with a Telesto-II OCT benchtop. The validation task consisted of an automatic spatial repositioning of the robotic structure to precisely retrieve the position of an initial optical biopsy. Several tests are achieved, which clearly demonstrate the reliability of the proposed controller.