Inclusion of peripheral correspondences in object and pose estimation for visual servoing path-planning

This article addresses the utilization of peripheral image correspondences obtained in cameras obeying the unified model for path-planning-based visual servoing applications. The proposed approach consists of reprojecting available image correspondences onto an oriented virtual plane, which is designed to carry as many reprojections as possible from correspondences, especially those in periphery region. To realize this, a key transformation matrix is proposed and applied to spherical projections of those correspondences. After this transformation, object and pose estimation are realized via the minimization of algebraic and geometric errors by introducing appropriate parametrization and strategies. The geometric error will be defined either on the virtual plane or on the spherical surface. Minimization of error function defined on the spherical surface provides much more accurate estimation results in object structure than that of other error functions as demonstrated in simulation examples. At last, experiment with a fisheye camera mounted on a robot validates the effectiveness of the proposed method.