Visual system
Vision is the system of human seeing. Good vision helps human detect all of dangerous effect. Vision enaple human to be aware of changing feature in the physical environment and adapt their behavior. The eye in the camera of human for the brain's motion picture of the world. There are two types of eye muscles: intraocular (inside the eye) muscles dilate or constrict the pupil and execute the focusing of the lens; extraocular (outside the eye) muscles direct the eye to locations of interest in the outside word. (Bridgeman and Tseng,2011). Scholar debated whether certain types of infromation (e.g., semantic components of word) can be processed without focal attention. Subsequently, Treisman proposed that there is a set of "preattentive visual features," such as colors, shapes, and orientations, which can be processed in parallel without focal attention but that more complex information needs to be processed serially with focal attention (Treisman, 1996). From another work reter contrast stimulus location and size of object can effect on visual system. Most of colors can be described in term of three physical dimension : wavelength intensity and purity. Colors is effect on brightness and saturation refer to color consists of light.