How to show coordinate points in a polar plot?

Hey,

I have a picture of a textile sample almost circle but strange shape. I have to evaluate the shape by means of polar plot and wave diagram. I need to get especially the coordinates of peaks(number of peaks) of this shape (curve), then express this curve into wave and find max and min amplitude (peaks and troughs of the curve), wavelength, height of wave. It means to convert polar plot into Cartesian..?? Or how can I get the wave diagram? I need to evaluate it like a signal..

I made basic processing(threshold,binary,edge´canny´, regionprops - area, centroid, perimeter, bwboundaries, polar plot and plot of rho and theta..) Here is link to see my pictures from image processing: http://www.imgup.cz/album/rh

Could please someone help me with my task? Any ideas..

Thanks for all answers!