Measurement of Geometric Dimensions of Hexagonal Type Washer Parts Using Machine Vision-Based Systems

In this study, a method is proposed for measuring the geometric properties of hexagonal precision adjustment washers. The method primarily involves measuring the hypothetical diameter that encompasses the outermost part of the hexagon and the key slot dimensions of the hexagon. For the key slot dimension, subpixel-based edge detection is performed following a preprocessing step. Subsequently, the enclosing circle and diameter are estimated based on the detected points. For the key slot measurement, the first step involves Hough transform-based line detection. By predicting the equations of the detected lines, the distances between the opposing lines are computed. According to the results, both the proposed diameter measurement algorithm and the key slot measurement algorithm function with an average error of approximately 13 μm in the utilized dataset. When considering part tolerances and average error amounts, it is concluded that the proposed algorithms are successful and feasible for practical use.