Abstract: Human visual search includes two interacting processes: A cover process(“look")and a vision process(“see"). The fundamental strategies for human visual search of a 2D scene include systematic and random cover patterns. Based on the experiment results, when search conditions are relative dificult, searchers usually conducted a random search. A probability formula for modelling random search performance is discussed in this paper. When the parameters are properly seleted, this model fits the experiment data quite well.

Key words: eye movements, saccade, random search, systematic search, probability, fixation