To develop the observation techniques of stomach and colon will result in an increase in the diagnostic availability of the stomach and colon cancer. Many visualization methods for non-invasive gastrointestinal (GI) tract diagnosis been proposed. Some of which have been developed and adopted in clinical applications, such as virtual colonoscopy and virtual flattening. The virtual eversion method allows the observation of the colonic mucosa under a global view while keeping the colon path preserved. Reviewin...