A system is described which is based on a unique weld image sensor design which integrates the optical system into the weld end effector to produce the so-called "coaxial view" of the weld zone. The resulting weld image is processed by a flexible, table driven vision processing system which can be adapted to detect a variety of features and feature relationships. Provision is made for interactive "teaching" of image features for generation of table parameters from test welds. A table driven control program allows various vision control strategies to be invoked. The main result of the system is a level of emulation of the capability of the expert welder or welding operator, essential to successful precision welding robotization.