1. A resolution conversion apparatus comprising: a first acquisition unit configured to acquire, from an image source, a target image as a target of resolution conversion; a second acquisition unit configured to acquire an additional image from the image source; an estimation unit configured to estimate a corresponding point in the target image using a plurality of corresponding point estimation methods, the corresponding point being associated with at least one pixel in the additional image to obtain a plurality of corresponding points in the target image; a setting unit configured to set 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 a plurality of sampling values for pixels included in the additional image; and a generation unit configured to generate an image of a first resolution into which a second resolution of the target image is converted, using pixel values and positions of a plurality of pixels included in the target image, and the sampling values and positions of the corresponding points.