An Application of Vision Systems for the Inspection of Two-Dimensional Entities in a Plane

摘要

This study proposes a method for measuring the dimensions and position of two-dimensional (2D) entities in a plane by using a vision system ( e.g., a camera). In the proposed method, a camera was installed in a non-orthogonal configuration to capture an image of 2D entities in a work plane. The plane of 2D entities possesses four reference points with their given coordinates. The image of entities captured in a non-orthogonal view was transformed into an orthogonal image by applying a homography transformation estimated from four reference points. Subsequently, the position and dimensions of 2D entities in the orthogonal image were detected automatically using some image processing algorithms that were implemented in MATLAB software. The position and dimensions of 2D entities in the world coordinate system were finally computed by using a ratio of millimeters per pixels. The accuracy and efficiency of the proposed method were validated through the case of measuring a set of milled holes.