This function calculates the weighted mean of previous three frames. The buffer maintained here can contain only three frames.
wtmean(b, nf, thresh)3-D matrix containing grayscaled video frames.
It is size of buffer that contains previous frames and its value can be set to three only.
threshold required to obtain foreground images.Its value can be around 10 - 30.
A 3-D matrix of frames containing foreground obtained after background subtraction is applied(binary images).