Stereo Vision System for Accurate 3D Measurements of Connector Pins' Positions in Production Lines

This paper addresses the need for a fast and precise non- contact measurement system to be used to assess the quality of connectors for electrical/electronic applications and particularly it proposes a technique to measure the position of the pins that are present in various shapes and number in every connector by a stereo vision system. The proposed stereo vision system is targeted to the automotive industry, but the same approach can be translated to many other sectors. The measurement of the position of the pins is a crucial aspect in assessing the quality both of the connectors (from the point of view of the connectors suppliers) and of the equipment where the connectors are used. It is of primary importance to verify the position of the pins not only in the 2D plane where they lie, but also to measure their height to verify that they can guarantee the continuity of the electrical circuit. In this paper, a technique based on the stereo vision principle is proposed to performsuch an analysis. The stereo vision system, developed for a real production line, is compared against other available non- contact techniques and its advantages in terms of resolution, speed and robustness are pointed out. The system is described in terms of hardware, layout and software. System calibration and performance are described and verified. Afterwards, the on line implementation is described and the advantages and critical points are highlighted.