Tangible Augmented Reality for Human Computer Interaction Hirokazu Kato1 , Mark Billinghurst2 , Ivan Poupyrev3 , Nobuji Tetsutani4 , Keihachiro Tachibana1 1 Hiroshima City University, 2 University of Washington, 3 Sony CSL, 4 ATR MIC Lab. Input Image Thresholding Image Extraction of Rectangle Region Pose and Position Estimation Virtual Image Overlay T. Höllerer et al.