Opencv multiply scalar and matrix

Question

I have been trying to achieve something which should pretty trivial and is trivial in Matlab.

I want to simply achieve something such as:

cv::Ma         


        

Answer 1

OpenCV does in fact support multiplication by a scalar value with overloaded operator*. You might need to initialize the matrix correctly, though.

float data[] = {1 ,2, 3,
                4, 5, 6,
                7, 8, 9};
cv::Mat m(3, 3, CV_32FC1, data);
m = 3*m;  // This works just fine

If you are mainly interested in mathematical operations, cv::Matx is a little easier to work with:

cv::Matx33f mx(1,2,3,
               4,5,6,
               7,8,9);
mx *= 4;  // This works too