Method and apparatus for inspection of specular, three-dimensional features

A method for inspecting an article to detect missing and defective specular, topographical features on its surface and deformations in the topology of such features comprising the steps of:

• (a) illuminating the surface of the article with a first light directed at an acute angle to the surface from all of the sides thereof;
• (b) capturing the image of the surface;
• (c) creating a window within the image about each group of specular, topographical features and subsequently creating a bounding box about each topographical feature within each window;
• (d) measuring the value of each of a first predetermined set of attributes associated with the windows, the boxes within the windows, and the feature inside each box;
• (e) comparing the measured value of each first attribute to a separate one of a set of reference values, each representing the value of the corresponding first attribute when no defect, such as a missing or deformed feature, is present, and identifying the existence of a particular type of defect when the established value of a separate one of the first attributes differs from its associated reference value by more than a predetermined tolerance.