1. An image processing method of capturing a display image of a display panel in which pixels are aligned periodically using a camera in which imaging pixels are aligned periodically, and processing the image captured by the camera, comprising: an in-focus image capturing step of capturing the display image in-focus using the camera; a first image generation step of generating a first image by applying a high-pass filter to the image captured in the in-focus image capturing step and removing or reducing a spatial frequency component corresponding to moiré that appears in the captured image; an out-of-focus image capturing step of capturing the display image out-of-focus using the camera; a second image generation step of generating a second image by applying a low-pass filter to the image captured in the out-of-focus image capturing step; and a third image generation step of generating a third image in which the moiré is eliminated or suppressed, by compositing the first image and the second image.