Efficient 3D Tracking for Motion Compensation in Beating Heart Surgery

International audienceThe design of physiological motion compensation systems for robotic-assisted cardiac Minimally Invasive Surgery (MIS) is a challeng- ing research topic. In this domain, vision-based techniques have proven to be a practical way to retrieve the motion of the beating heart. However due to the complexity of the heart motion and its surface characteristics, efficient tracking is still a complicated task. In this paper, we propose an algorithm for tracking the 3D motion of the beating heart, based on a Thin-Plate Splines (TPS) parametric model. The novelty of our approach lies in that no explicit matching between the stereo camera images is re- quired and consequently no intermediate steps such as rectification are needed. Experiments conducted on ex-vivo and in-vivo tissue show the effectiveness of the proposed algorithm for tracking surfaces undergoing complex deformations

Recovery and tracking of continuous 3D surfaces from stereo data using a deformable dual-mesh

We propose a novel method for continuous 3D depth recovery and tracking using calibrated stereo. The method integrates stereo correspondence, surface reconstruction and tracking by using a new single deformable dual mesh optimization, resulting in simplicity, robustness and efficiency. In order to combine stereo correspondence and structure recovery, the method introduces an external energy function defined for a 3D volume based on crosscorrelation between the stereo pairs. The internal energy functional of the deformable dual mesh imposes smoothness on the surfaces and it serves as a communication tool between the two meshes. Under the forces produced by the energy terms, the dual mesh deforms to recover and track the 3D surface. The newly introduced dualmesh model, which is one of the main contributions of this paper, makes the system robust against local minima and yet it is e#cient. A coarse-to-fine minimization approach makes the system even more efficient. Tracking is achieved by u..