To allow an observer wearing stereoscopic equipment to perceive a stereo image and an observer not wearing stereoscopic equipment to perceive a clear image. Based on an original image, an image containing phase-modulated components a and an image containing phase-modulated components b are generated. The image containing phase-modulated components a and the image containing phase-modulated components b are for one who sees the original image or a subject represented by the original image and the image containing phase-modulated components a with one eye and sees the original image or the subject and the image containing phase-modulated components b with the other eye to perceive a stereo image, and one who sees the original image or the subject, the image containing phase-modulated components a, and the image containing phase-modulated components b with the same eye(s) to perceive the original image. The phase-modulated components a are generated by shifting the phase of spatial frequency components of the original image by a first phase, and the phase-modulated components b are generated by shifting the phase of the spatial frequency components of the original image by a second phase being a different phase than the first phase.