In order to run the program:

1. run the command : (assuming you have a c++ compiler installed & set in matlab)  
>> compile_gc

2. open the file GC_GUI.m, and run it.

3. use the "open" button to open an image.

4. (optional & recommended) download the cambridge data images & rectangles (polygons) from here:
   a. http://research.microsoft.com/en-us/um/cambridge/projects/visionimagevideoediting/segmentation/DATA/data_GT.zip
   b. http://research.microsoft.com/en-us/um/cambridge/projects/visionimagevideoediting/segmentation/DATA/boundary_GT_rect.zip

5. a. you can load a polygon using "Load Polygon" from a file (a rectangle from step 4b for example ) or
   b. you can press "Mark Polygon" and mark a polygon using left mouse to pin a vertex and right click to close the polygon.

6. Change K & Beta to your choise.

7. pres "Run".

8. Repeat steps 6 + 7 as long as you desire.

Enjoy !