An image processor includes an image generator configured to generate corresponding image data corresponding to first microscopic image data obtained under a first observation condition, based on second microscopic image data and third microscopic image data obtained under a second observation condition, and an image output unit configured to output the corresponding image data. The corresponding image data may be image data corresponding to a first focal plane from which the first microscopic image data are obtained, and wherein the second microscopic image data and the third microscopic image data may be image data on a second focal plane and a third focal plane, respectively, which are different from the first focal plane.