Discreet points of a picture outline

Hi, I need to show each point (value) creating the outline, where x represents the angle of each point in degrees (0-360) and y is distance (radius) of each point from the centre. So, I have to know radius r(i) of each point as well. Then I need to get peaks and throughs of this curve.. I have bw image(white contour on black background), I used edge detection (´canny´), bwboundaries, regionprops (area, perimeter, centroid, EquivDiameter), I have coordinates of the picture x=b(:,2), y=b(:,1), Cartesian plot, polar plot. I don´t know how to continue..Could someone help please..any ideas?

link on illustrative pictures: http://www.imgup.cz/user/iris333

Thanks everyone!