Cropping and lifting up an irregular-shaped sub-image from an image

This function lets the user define an irregular, possibly concave domain to lift an sub-image.

This program is useful for image segmentation, processing and registration. User needs to input the name of image and the number of points needed to define the area. Example command line:
y=liftImage2d(movingimage, 5)
The image is from a plastic pelvic phantom.

You could also use this to crop your favorite part of your picture for further processing.