According to an image processor of one embodiment, a first acquirer acquires a first perspective image of a target, which has a first resolution. A second acquirer acquires a second perspective image of the target, which has a second resolution. A first image generator generates first and second display images respectively from the first and second perspective images. The first and third display images have a third resolution lower than at least one of the first and second resolutions. A first point acquirer acquires first and second corresponding points respectively on the first and second display images. A first corrector searches, on the second perspective image, a second image similar to a first image on the first perspective image, the first image including the first corresponding point, and changes, on the second perspective image, a position of the second corresponding point to a position of the second image.