disparity for points in the unrecitifcated image

Question

In stereo imaging, images are rectified before disparity calculation. Points in disparity map corresponds to points in the rectified image. If I hope to know corresponding points in unrectified image, so I need to apply inverse operation of rectification to disparity map. Am I right? Is there any such function in OpenCV?

Answer 1

I am not aware of any function in opencv which directly gives you this result. But this is the hack I used.I guess you can use the map function obtained in stereoRectify function.Something like this. Though code is self explanatory, but if you need some help feel free to ask.

`

for(int row = 0; row < noRows; row++)
    {
        for(int col = 0; col < noCols; col++)
        {
           float disp = imgDisparity.at<float>(row, col);
            if(disp > 0) // valid disparity only
            {
                Vec2s v1, v2;
                int x1, x2, y1, y2; // corresponding coordinates
                v1 = mapL.at<Vec2s>(row, col);
                v2 = mapR.at<Vec2s>(row, col - (int)disp);

                x1 = v1[0];
                x2 = v2[0];

                y1 = v1[1];
                y2 = v2[1];
             }
           }
         }

`