how to estimate background of a sequence of images using motion saliency map

i have a sequence of frames in a folder and i have to estimate the background of that sequence.i am using motion saliency map generation method for it.i have to use the background for my further work of moving object detection.For the motion saliency map the steps are as- 1.Initialize the saliency matrix S=0 2.For each i from 1 to n 3.{ 4.calculate the difference matrix between two adjascent frames.ie Dt,t-i and Dt,t+i 5.Take array multiplication of Dt,t+i and Dt,t-i ie Di=Dt,t+i * Dt,t-i 6.Perform morphological opening on the difference matrix D1i=imopen(Di) 7.} 8.The motion saliency matrix S=sum from i=0 to n(D1i). hense i will obtained a averaged image which will be my background reference image.