C# - get averaged desktop/background color

I need C# code, in method with parameters for Top Left, Bottom Right corners of a rectangular area of the desktop. The method will get a screen capture of the desktop, and consider only the rectangular region of it, ( for example, a 200x400 pixel area), and calculate the average color. I need a clever efficient calculation of average color. return the color. A crude user interface in a simple app that lets me test that it works, is requested. (but ultimately, all I need is the algorithm to capture, get rectangle content, and average it. ) ## Deliverables * * *This broadcast message was sent to all bidders on Friday Jul 22, 2011 2:39:48 PM: Several bidders have asked for more clarification about what is the "average" color. Here's what Photoshop's filter creates for Blur->Average, shown on this example gif at [login to view URL]