用帧差分可以检测场景变化，一个简单帧差分可通过计算两个连续帧的象素获得。对帧内每个象素点（x,y），T时刻与T－1时刻象素值之差为Dx,y(T)=||Sx,y(T) – Sx,y(T-1)||。设定内帧差分系数IDsum=ΣL , IF ||Sx,y(T) – Sx,y(T-1)||≥Ta THEN L=TRUE，实际决定是否报警,可以通过计算三帧以上IDsum数量-fr a me difference can be detected with the scene changes, a simple fr a me difference of two consecutive fr a mes can be calculated to obtain the pixel. Right fr a me of each pixel (x, y), T and T-1 time point pixel value difference of Dx, y (T) = | | Sx, y (T)- Sx, y (T-1 ) | |. Set within the fr a me differential coefficient IDsum = ΣL, IF | | Sx, y (T)- Sx, y (T-1) | | ≥ Ta THEN L = TRUE, the actual decision of whether or alarm, you can calculate the number of three or more IDsum