US Patent 7590280 Position detection apparatus and exposure apparatus

An exposure apparatus for exposing an object to light. The apparatus includes a camera which captures an image of a mark on the object to obtain image data corresponding to the image, an extraction section which extracts an edge position in the image data obtained by differentiating the image data, a determination section which determines a position of the mark by comparing the extracted edge position with a template, and a control section which changes at least one of a parameter used by the extraction section and a parameter used by the determination section, based on a result of the comparing by the determination section. The object to be exposed is positioned based upon the position of the mark determined by the determination section.