Aiming at problem that visual background extraction（ Vi Be） algorithm is prone to produce ghost when initializing the background model and its adaptability is poor in outdoor dynamic scenes and the detection precision is low

an improved visual background extraction algorithm is proposed. In initial stage of the algorithm

to improve precision of the algorithm

the ghost is effectively suppressed by counting the percentage of still pixels in foreground blocks. In the foreground detection stage

improve the adaptability in dynamic scenes

dynamically adjust threshold according to the scene dynamic degree. Experimental results demonstrate that precision of this algorithm is improved by 20 % compared with the original Vi Be algorithm.