An apparatus includes unit acquiring a target image as a target of resolution conversion, unit acquiring an additional image from the image source, unit estimating a corresponding point in the target image using corresponding point estimation methods, the corresponding point being associated with at least one pixel in the additional image to obtain corresponding points in the target image, unit setting a pixel value of each pixel included in the additional image as a sampling value for the corresponding point when each pixel is set as a target pixel, to obtain sampling values for pixels included in the additional image, and unit generating an image of a first resolution into which a second resolution of the target image is converted, using pixel values and positions of pixels included in the target image, and the sampling values and positions of the corresponding points.