An apparatus includes a stereoscopic display region calculator calculating a stereoscopic display region to reproduce a three-dimensional positional relationship in image data displayed on a stereoscopic display device, based on two-dimensional or three-dimensional image data, a position of a target of regard of a virtual camera set in processing of rendering the image data, and orientations of the light beams output from the stereoscopic display device. The apparatus also includes an image processor performing image processing on image data outside a region representing the outside of the stereoscopic display region calculated by the stereoscopic display region calculator. The image processing is different from image processing on image data inside a region representing the inside of the stereoscopic display region. The apparatus also includes an image generator generating stereoscopic display image data from the two-dimensional or three-dimensional image data after processed by the image processor.