1. An image processing apparatus comprising: a template image extracting section that extracts a template image from blade images obtained by capturing blades periodically arrayed in a jet engine; an image comparing section that compares the template image with the blade images; an image selecting section that selects an image from the blade images based on a result of the image comparison of the image comparing section; and a first difference extracting section that extracts a difference between the template image and the image selected by the image selecting section.