LOCATING AN IMAGE OF AN OBJECT HAVING A CONCENTRIC PROFILE

A method is provided for finding an image of an object having a concentric profile, wherein the concentric profile has an inner profile and an outer profile, and wherein the inner profile is in concentric relationship with the outer profile. In another general aspect of the invention, a method is provided for finding an image of an object having a concentric profile, the concentric profile having a plurality of constituent profiles, where each profiles of the plurality of constituent profiles scales independently in a fine search phase. The methods of the invention can find circular profiles of a nozzle that scale non-uniformly as well as that scale uniformly, and therefore can be used to find one or more rings or profiles of the image of a nozzle. Further, the methods of the invention can provide superior accuracy regarding the position of the nozzle for many applications. Moreover, certain aspects of the relationship between the inner and outer profiles of the image of the nozzle, such as a bent nozzle condition, can be effectively inspected by the methods of the invention.