1.初始化矩阵: 
方式一、逐点赋值式: 
CvMat* mat = cvCreateMat( 2, 2, CV_64FC1 ); 
cvZero( mat ); 
cvmSet( mat, 0, 0, 1 ); 
cvmSet( mat, 0, 1, 2 ); 
cvmSet( mat, 1, 0, 3 ); 
cvmSet( mat, 2, 2, 4 ); 
cvReleaseMat( &mat ); 

方式二、连接现有数组式: double a[] = { 1,  2,  3,  4, 5,  6,  7,  8, 9, 10, 11, 12 };         

CvMat mat = cvMat( 3, 4, CV_64FC1, a ); // 64FC1 for double 
// 不需要cvReleaseMat,因为数据内存分配是由double定义的数组进行的。

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