c# Image edge detection method

Let my try to be clear about this bid. 1. I need (1)one method. 2. This method should accept an image and return an image. 3. The class should remove information on the outside of an image using some kind of edge detection. 4. I have included an image so you get the idea of what I am asking for. 5. The image can be anything (did I mention the image can be anything?) 6. I will not be able to send you more sample images it can be anything and everything. 7. It must read from the outside and get the first continuous region it finds and the image that is returned should be the image that is INSIDE the region. 8. The OUTSIDE of the region should be transparent. 9. All the information INSIDE the region should be the image that is returned in the method. 10. Remove the part of the image that is outside the image and make it transparent. This is my third post for this same thing I really need this project completed with this method. Thank you and good luck..................