1. An image generation method for generating image information of a second color signal Y of a first image A by using a first color signal X of the first image A, and the first color signal X and the second color signal Y of a second image B, the method comprising: a corresponding point estimating step that estimates presence or absence of a point in the first color signal X of the second image B corresponding to each pixel position of the first color signal X of the first image A and also estimates the position of the relevant corresponding point; a corresponding image assigning step that assigns, to each pixel position in the second color signal Y of the first image A for which the corresponding point estimating step estimates that there is a corresponding point, image information of the corresponding position in the second color signal Y of the second image B; and an image interpolation step that generates the second color signal Y at a pixel position in the first image A for which the corresponding point estimating step estimates that there is no corresponding point, by means of interpolation using the image information of the second color signal Y assigned by the corresponding image assigning step.