1. An image processing system, comprising: an image capturing apparatus that (i) has an optical system in which a size of point image spread is equal to or more than twice as a dot pitch and an optical transfer function is substantially constant over a predetermined object distance range on an optical axis and (ii) captures an original image, in which a subject image is blurred, by receiving light from the subject that passes through the optical system at a light receiving element; and an image processing apparatus that acquires, from the image capturing apparatus, the original image captured by the image capturing apparatus and a machine ID that identifies the image capturing apparatus, wherein the image capturing apparatus (i) generates the original image based on an amount of the light received at the light receiving element without performing an image processing that changes spatial frequency characteristics of an image including edge enhancement processing and (ii) provides the generated original image and the machine ID to the image apparatus and the image processing apparatus comprises: an original image acquiring section that acquires the original image from the image capturing apparatus; a characteristic region judging section that makes a judgment as to whether a characteristic region is present in the original image acquired by the original image acquiring section; an image adjusting section that, in a case where the characteristic region judging section makes a judgment that the characteristic region is present, reproduces an image of the characteristic region in the original image acquired by the original image acquiring section by applying reverse filtering according to the optical transfer function corresponding to the machine ID acquired from the image capturing apparatus; and an image output section that, in a case where the characteristic region judging section makes a judgment that the characteristic region is present, outputs, to an image display apparatus, an image in which the image of the characteristic region is reproduced by the image adjusting section and, in a case where the characteristic region judging section makes a judgment that the characteristic region is not present, outputs, to the image display apparatus, the original image acquired by the original image acquiring section.