Machine vision system for object feature analysis and validation based on multiple object images

Abstract

Provided is the ability to validate detected features in acquired images to thereby enhance the integrity of any analysis carried out on the detected and validated features. A sequence of images of, e.g., an object is acquired, each image in the sequence corresponding to a distinct orientation of the object about a selected object axis. Images in the sequence are inspected for feature points of the selected feature plane, as-projected into the images, at a first feature detection location and at a second feature detection location. The second feature detection location is configured at an image position at which a feature point detected in the first feature detection location in a first inspected image is expected to appear in a second inspected image. Valid object feature points are identified as being those feature points which are detected in both the first feature detection location in a first inspected image and in the second feature detection location in a second inspected image of the image sequence. Features that are validated are not likely to be time-dependent noise and are preserved for further feature analysis, while extraneous data is rendered transparent to feature analysis. Further, an object feature plane can be analyzed for a specified feature configuration even when only a subset of feature points is available in any one given image of the object, e.g., where a portion of a three-dimensional object obscures other portions of the object in a selected view of the object. Also provided is a method for detecting features of a semiconductor melt surface as a semiconductor ingot is pulled out of the melt.