background and aims: in diagnosing inflammatory bowel disease, one of diagnostic way is upper gastrointestinal endoscopy, which helps in differential diagnosis of unspecified colitis as well. the aim of this study was to investigate the necessity of upper gastrointestinal endoscopy in patients with inflammatory bowel disease.   materials and methods: in this descriptive cross-sectional study, 3...

We introduce a new metric for dynamic range of displays that closely corresponds with human perception in practical settings. The Number of Distinguishable Grays is a count of the visible luminance steps from the deepest black to the brightest white a display produces under known ambient conditions.