oencv学习（9）cvsum()求矩阵和以及全部额平均数

double m[4][4] = {1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0,9.0,10.0,11.0,12.0,13.0,14.0,15.0,16.0};   
Mat M = Mat(4, 4, CV_64F ,m); 

Scalar sca=sum(M);
double sum= sca.val[0]; 
cout<<sum<<endl;
cout<<sum/(M.rows*M.cols)<<endl;

相当于matlab两次means()