1. A method of processing image data, comprising: providing a template representative of an image of a human face; rotating at least one of the template and the image data to adjust a relative angle between an original orientation of the template and an original orientation of the image data, so as to exclude an angle range including 180 degrees; examining a matching between a part of the image data and the template to identify a region in the image data containing an image of a human face; and correcting the image data in accordance with a condition of the image of the human face.