How to wrap a selective part of a image?

for a image, a region will be selected by some point, and the points should be select on mouse click. After getting points a model of shape is build. But after building the model, I want to build another model by intensity values. For that I have to wrap the whole selected part and get the intensity values. But I dont know how to do this wrapping portion! can any one help me plzzzz. Thanks in advance.

[Xylo]

like this picture.........