How Many Pixels Do We Need to See Things?

Today’s computer display devices normally provide more information than we need. In this paper, the author presents an empirical model that shows minimal pixel requirements for computer users to recognize things from digital photos under different contextual conditions. It is found that face recognition alone needs far fewer pixels than people normally thought. However, more pixels are needed for users to recognize objects within outdoor scenes and paintings. Color and age have effect on object recognition but the differences are not significant. The results can be applied to adaptive display design, computer vision, adaptive human-computer interaction and telecommunication system design.