According to one embodiment, an image processing device includes a hardware processor implemented by one or more processors. The hardware processor acquires a first image of a first object and a second image of a second object which is different from the first object, the images captured by an image capture processing device including an image capturing element and an optical system which images an object image on an image capturing surface of the image capturing element. The hardware processor measures a point spread function of the optical system based on the first image and the second image.