How to locate pixel coordinates

How can I find the coordinates of a pixel corresponding to a corner point?

Answer 1

[Image Analyst]

Well first I'd read this: http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer. Then I'd find the corner point from some algorithm, such as the built-in corner().