This is the inverse of ImToPolar. imP is the polar image with M rows and
N columns of data (double data between 0 and 1). M is the number of
samples along the radius from rMin to rMax (which are between 0 and 1 and
rMax > rMin). Mr and Nr are the number of pixels in the rectangular
domain. The center of the image is assumed to be the origin for the polar
co-ordinates, and half the width of the image corresponds to r = 1.
Bilinear interpolation is performed for points not in the imP image and
points not between rMin and rMax are rendered as zero. The output is a Mr
x Nr grayscale image (with double values between 0.0 and 1.0).