This rectangle and ellipse graphical interface selection tool allows you to make any number of selection you want on an image your provide. You can then resize, move or delete those selections. When you quit the application, the coordinates of the first corner and the width and height of each selection is returned.
It's then pretty straighforward to get the inside pixels coordinates for each of the selection. Contact me if you need help on this.
Read the documentation at the beginning of the code.
>> selectROI() %will run the application using default picture and selection