Visual Servoing Based on Shifted Moments

Overview & Synopsis

—In the last decade, image-moments have been exploited in several visual servoing schemes for their ability to represent object regions, objects defined by contours or a set of discrete points. Moments have also been useful to achieve control decoupling properties and to choose minimal number of features to control the whole degrees of freedom of a camera. However the choice of moment-based features to control the rotational motions around the x-axis and y-axis simultaneously with the translational motions along the same axis remains a key issue. In this paper, we introduce new visual features computed from low order 'shifted moments invariants'. Importantly, they allow (1) to define a unique combination of visual features to control the whole 6 DOF of a eye-in-hand camera independently from the object shape and (2) to significantly enlarge the convergence domain of the closed loop system.