1. An image processing device, comprising: a first area setting unit that sets, within a target image, a plurality of first areas for specifying a characteristic area of the target image; a first calculation unit that calculates, as to each of the plurality of first areas, a total value of edge amounts of pixels within the first area; a characteristic area detection unit that specifies the characteristic area, based on the total value of each of the plurality of first areas; a second area setting unit that sets, within the target image, a plurality of second areas for determining a display area of annotation information; a second calculation unit that calculates, as to each of the plurality of second areas, a total value of edge amounts of pixels within the second area; and an annotation information display area determination unit that determines the display area of the annotation information, based on the total value of each of the plurality of second areas and the characteristic area.