int MOMENTS_M(IplImage* img,int p,int q)   //计算空间距
{
       CvScalar scl;
       float M_sum_y=0;     
       float M_sum_xy=0;
       int H,W;
       H=img->height;
       W=img->width;

       for(int i=0;i<H;i++)
       {     
             float M_sum_y=0;

              for(int j=0;j<W;j++)
              {
                     scl=cvGet2D(img,i,j);                               // 获取img图像中坐标为（i,j）的像素点的值，
                                                                          // scl.val[0] 代表img图像BGR中的B通道的值  20121204            
                     M_sum_y+=pow(double(j),double(q))*scl.val[0];            
              }  
              M_sum_xy+=M_sum_y*pow(double(i),double(p));                //乘幂运算 pow(x,y) 表示 x 的 y 次幂 20121204
       }

       return M_sum_xy;
}