1. An image processing method comprising: acquiring an original image; acquiring position information indicating a position of a viewer in a depth direction with respect to a display unit; acquiring crosstalk information indicating a crosstalk characteristic of the display unit; causing a processor to generate an index map that includes control information indicating a correspondence between respective pixels of the display unit and a respective plurality of viewpoints that is based on the position information on the basis of the acquired position information and the acquired crosstalk information in a manner that, among first viewpoint images which are different from each other based on the original image corresponding to the respective plurality of viewpoints set in advance, one of the first viewpoint images is observed while crosstalk is negated at a position indicated by the position information; and outputting second viewpoint images corresponding to respective pieces of the control information included in the index map based on the original image and the index map.