Methods and apparatuses for generating from an image a model of an object

The invention provides methods and apparatuses for generating from an image of an object a model of the object, when the object contains similar features. First, the invention finds the similar features. The similar features are found by searching portions of the image for features that are substantially similar to a feature prototype. More particularly, individual features in the image are located and designated candidate features, and optionally a spatial pattern representing a majority of the candidate features is generated. Next, feature profiles are generated therefrom, and the feature prototype is constructed using at least a subset of feature profiles. Thereafter, the model is generated using the similar features and, optionally, the spatial pattern. An example is described wherein the model is of a ball grid array, the similar features are the solder balls on the ball grid array, the feature profiles are local images of balls of a ball grid array, and the feature prototype is an average of a sub-set of the local images of the balls.