实现了图像的灰度化并进一步用于视频监视控，最大似然（ML）准则和最大后验概率（MAP）准则，用平面波展开法计算二维声子晶体带隙。- Achieve a grayscale image and further control for video surveillance, Maximum Likelihood (ML) criteria and maximum a posteriori (MAP) criterion, Computation Method D phononic bandgap plane wave.