Currently, new imaging technologies have applied in endoscopy to improve detecting and differentiating the subtle mucosal changes using digital contrast method such as narrow−band imaging (NBI), Fuji Intelligent Chromoen−doscopy (FICE) and i-scan. Among them, i-scan technology is the most recently developed image enhancing technology, which consists of three modes of image enhancement, i.e. surface enhancement (SE), contrast enhancement (CE), and tone enhancement (TE). SE enhances light-dark contrast and CE adds blue color in relatively dark areas digitally, by obtaining luminance intensity data for each pixel. Applying SE and CE might allow detailed observation of subtle irregularities around the surface and TE analyzes the individual RGB components of a normal image and recombines the color frequencies of each component to enhance minute mucosal structures with subtle color changes.