1. An image processing apparatus comprising: first background image generating unit for generating a first background image corresponding to a first image captured at a predetermined image magnification; first object image extracting unit for extracting a first object image from the first image; second background image generating unit for generating a second background image corresponding to a second image captured at an image magnification higher than the predetermined image magnification, based on the first background image and the first object image; and second object image extracting unit for extracting a second object image from the second image and the second background image.