Grasping visual symmetry

The authors discuss establishing a relationship between symmetry and two-fingered grasping of planar contours. Visual representations are chosen to meet the requirements of specified tasks such as object recognition or stereoscopic matching. When vision is regarded as a haptic sense, a new operational description is called for in support of dextrous manipulation. In the context of two-fingered grasp, an appropriate description can be constructed in terms of local reflectional and rotational symmetry. Related to symmetry-based representatons that have been used in pattern and object recognition, its structure is determined not heuristically, but precisely, by the nature of the grasping task. Its value is demonstrated by its incorporation into the control of a robot that can manipulate objects under visual guidance