Indication position estimation method using the homography between planes

To get a rapid estimation of the user′s indication position in the computer vision based non-contact human-computer interaction(HCI) system,an indication position estimation method without explicitly calculating the camera parameters was proposed.The homography matrix was calculated using the known points on the target plane and their corresponding points imaged by the cameras.By the homography relationship,the two lines which intersect at the indication point on the target plane were related with their corresponding lines on the image plane,thus the position of the indication point is estimated by detecting specific lines from images.Experimental results show that the average error of the homographic mapping is 0.73 mm at the distance of 2.5 m.Meanwhile,the amplitude of errors rises by 2.6% from the center to the fringe of the screen.