Background clutter plays a very important role in the area of human-in-the-loop target acquisition.To model the target acquisition capability of an electro-optic system operated by a human,one should take into account how the clutter in the scene affects the human performance.Based on the classic probability of edge(POE) metrics for quantifying background clutter,and the up-to-date research findings in human visual perception,a new method for modifying NVESD's classic human target acquisition performance was proposed.And the modified model was preliminarily validated.