I follow the following tutorial:
http://docs.opencv.org/doc/tutorials/features2d/feature_homography/feature_homography.html#feature-homography
And I can detect the object I want. But I would like to know the position, and the coordinate is relative in the scene image. And I take the source code's scene_corners vendor, but the position is totally wrong. How can I transfer it the the right position? Thanks.