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c++imageopencvmat

getting error in calculating the Magnitude and Orientation of a Mat Using c++ and opencv

I want to get the magnitude and orientation of all pixel values in an image. This is what I have done until now:

cv::Sobel( dis, grad_x, dis.depth(), 1, 0, 3);     
cv::Sobel( dis, grad_y, dis.depth(), 0, 1, 3); 
Mat orientation(width, height, CV_32FC1);

#define PI 3.14159265
 for(int i = 0; i < grad_y.rows; ++i){
  for(int j= 0; j< grad_y.cols; ++j){
       orientation = atan( grad_y / grad_x ) * 180/PI ;
       magnitude= sqrt((grad_x)*(grad_x)+(grad_y)*(grad_y));
  }
   }

but I get this error in atan and sqrt lines :

error C2665: 'atan' : none of the 3 overloads could convert all the argument type   
 math.h(108):could be 'double atan(double)
 math.h(505):float atan(float)
 math.h(553):long double atan(long double)

does anyone know what is the problem?

Thanks in advance...

-----------After Editing-------------

#define PI 3.14159265
  for(int i=0; i<grad_y.rows; i++){
    for(int j=0; j<grad_y.cols; j++){
        orientation = atan( grad_y.at<float>(i,j) / grad_x.at<float>(i,j) ) * 180/PI ;
    }
}

I changed the sqrt into this but still I get error:

 Mat magnitude(m_pmdDevice->GetY(), m_pmdDevice->GetX(), CV_32FC1);
    Mat gradAdd(m_pmdDevice->GetY(), m_pmdDevice->GetX(), CV_32FC1);
    grad_x = grad_x.mul(grad_x);
    grad_y = grad_y.mul(grad_y);
    cv::add(grad_x, grad_y, gradAdd);
    magnitude = sqrt(gradAdd);
Solution

  • atan should get number (double, float or long), but you are providing matrix. You should use

    orientation = atan( grad_y.at<float>(i,j) / grad_x.at<float>(i,j) ) * 180/PI ;

    I wrote 'float' in my example since I don't know what type you are actually using. Replace it if necessary.

    Same problem in sqrt.

    Edit (after edit of question):

    You are using sqrt in the wrong way. See its documentation. It should be:

    sqrt(gradAdd, magnitude);

    Even better will be to use function magnitude instead of all the multiplications and square roots:

    magnitude(grad_x, grad_y, magnit);

    Also I recommend you not to give names to matrices that are functions of OpenCV. This will create confusion.