Inverse cv::linearPolar causes missing patch in output

edit

I'm trying apply an inverse linear polar transform to some quadratic images:

The result, I'd expect is the following (done using Photoshope):

However, the result I get from OpenCV's linearPolar function is the following:

Some part of the image is missing and can be noticed as a black slice.

The code I am using is:

linearPolar(in, pol, 
        Point2f(in.cols / 2, in.rows / 2), (in.rows / 2), 
        CV_WARP_FILL_OUTLIERS | CV_INTER_LINEAR | CV_WARP_INVERSE_MAP);

Where in is the input image, given by imread.

Am I doing something wrong here?