[英]accessing element in an openCV homography matrix
I have a 3x3 homography matrix , which I computed using findHomography() function. 我有一个3x3单应性矩阵,该矩阵是使用findHomography()函数计算的。 I store it in a cv::Mat matrix.
我将其存储在cv :: Mat矩阵中。
I am trying to do element access using the following code 我正在尝试使用以下代码进行元素访问
float cvHomography::accessElements(const cv::Mat& aCvMat)
{
//cout << aCvMat << endl;
const float* Mi;
for( int i = 0; i < aCvMat.rows; i++){
Mi = aCvMat.ptr<float>(i);
for( int j = 0; j < aCvMat.cols; j++){
cout << Mi[j] << endl;
}
}
}
The above does not return the correct value from the homography matrix. 上面没有从单应矩阵返回正确的值。 I have searched through documentation , tutorials and google and I honestly cannot see what I am doing wrong.
我已经搜索了文档,教程和google,但老实说我看不到我在做什么错。
This should work (if you are sure that type of the image is CV_64F): 这应该可以工作(如果您确定图像类型为CV_64F):
void cvHomography::accessElements(const cv::Mat& aCvMat)
{
// assert aCvMat.type() == CV_64F
for( int i = 0; i < aCvMat.rows; i++){
for( int j = 0; j < aCvMat.cols; j++){
cout << aCvMat.at<double>(i,j) << endl;
}
}
}
Also an overloaded operator << for std::ostream works with cv::Mat if you would like just to display image elements. 如果您只想显示图像元素,则std :: ostream的重载运算符<<也可与cv :: Mat一起使用。
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