An image processing system, an apparatus, a method and a medical image diagnostic apparatus

In an image processing system, a selecting unit selects a group of reference parallax images to be used as a reference, from among a plurality of groups of parallax images generated from image data taken chronologically; an image quality changing unit changes an image quality of at least one selected from between the selected group of reference parallax images and a group of parallax images contained in the groups of parallax images; and a display control unit causes images to be displayed that are formed by combining the group of parallax images contained in the groups of parallax images with the image-quality-changed group of reference parallax images, or by combining the selected group of reference parallax images with the image-quality-changed group of parallax images, or by combining together the image-quality-changed group of reference parallax images and the image-quality-changed group of parallax images contained in the groups of parallax images.