Get the position of specifed pixels

Hi! I have a problem.I have I picture with a rectangle in it.I can draw the boundary (edge detection) of that rectangle but how can I get the position of one of its corners because I want to use that point as the origin of a coordinate system.Please tell me how can I do that and thanks a lot.

Answer 1

[Walter Roberson]

convert the image to black and white, "label" the image, and use regionprops() to find the bounding box of the object.