1. An image processing method comprising: a first step of performing predetermined vector transformation with respect to an original image to calculate an image feature vector; a second step of obtaining a characteristic of a subject appearing in the original image, and calculating a physical characteristic parameter of the original image from the obtained subject characteristic; a third step of transforming the image feature vector with reference to the physical characteristic parameter to sharpen the original image; and a fourth step of subjecting the transformed image feature vector to transformation inverse to the predetermined vector transformation, to generate a new image, wherein the obtained subject characteristic is at least one of material information of the subject and distance information from a camera to the subject.