Investigation On Temporal Property Of Human Visual System

The temporal response property of human visual systems represents the capability of capturing the true images of changing objects and determines whether we can acquire the physical location of a moving object. So it has attracted the public attention in biology, telecine, image processing and psychology, and so on. However, the temporal response property of human visual system remains indeterminate for the mechanisms of transuding and processing image signals are so intricate. The previous studies regarded response of visual systems as an exclusive temporal factor, which resulted in many disagreements and made some interpretations quite hard. This paper indicates that the temporal response property of human visual systems include visual response latency and dynamic response characteristics. Further, the measurements for these two characteristics are studied based on the principle of system identification.First, using the principle of mislocalization during the smooth pursuit, let observes track the moving object and mark the position of the object. Then, convert the test of latency time to the test of error distance using the relationship of distance, time and motion speed. More important is that for the first time we point out that human visual system response latency is different when stimulated with light and dark things. Visual response latency to bright things is 74ms, but to the dark things is 106ms. The results content the research of visual system's property.Secondly, use time adjustable pulse signal as the stimulus of the system, complete the test of dynamic property of visual system through behavior experiments. Test results show that the relationship between perceived brightness and its response time follows an exponential function in photopic vision, which reveals the process of how a new image is built. Then, fit the test results with mathematical functions and the mathematical model of visual system can be built up in this test condition.After griping the two temporal properties and analyse the relationship between them, we found that the dynamic response is one of the reasons which result to response latency of visual system. Further, the above results successfully account for the mechanisms of motion smear, images fusion and relative visual phenomena which were doubted and debated for a long time.