A) An example of normal squamous tissue of the esophagus, identified by flat, stratified cells. B) An example of nondysplastic Barrett’s esophagus, characterized by large white goblet cells filled with mucus and ovoid glands reminiscent of intestinal tissue. C) An example of dysplasia of the esophagus in which nuclei become more prominent with varying sizes and shapes (pleomorphism) and glands become more crowded. The bottom three examples are instances of open-set data which are data points that do not belong to any of the three classes in-question. They can include patches that add no information, tissue of a different type (e.g. gastric and muscular tissue), and areas of the image that contain sensor noise.