Patent 7620206 was granted and assigned to Sony on November, 2009 by the United States Patent and Trademark Office.
To make it possible to accurately track a prescribed part a low-resolution overall image is taken in from an input image, and a medium-resolution image, whose center is the head part, is extracted from it. When it is possible to extract a medium-resolution image in the middle of which is the head part, an even higher-resolution image is extracted, in the middle of which is the two-eyes part.