best_background_image自适应门限背景抑制法的门限的确定是基于统计参数的自适应计算，该方法比传统的频域、空域高通滤波器具有速度快、效果好-Best_background_image adaptive threshold method of background suppression threshold determination is based on the statistical parameter adaptive calculation, this method than the conventional frequency domain, the airspace high-pass filter with high speed, the effect is good