PT Journal AU Zollmann, S Langlotz, T Bimber, O TI Passive-Active Geometric Calibration for View-Dependent Projections onto Arbitrary Surfaces SO JVRB - Journal of Virtual Reality and Broadcasting PY 2007 VL 4(2007) IS 6 DI 10.20385/1860-2037/4.2007.6 DE dynamic geometric calibration; optical flow; projector-camera systems AB In this paper we present a hybrid technique for correcting distortions that appear when projecting images onto geometrically complex, colored and textured surfaces. It analyzes the optical flow that results from perspective distortions during motions of the observer and tries to use this information for computing the correct image warping. If this fails due to an unreliable optical flow, an accurate -but slower and visiblestructured light projection is automatically triggered. Together with an appropriate radiometric compensation, view-dependent content can be projected onto arbitrary everyday surfaces. An implementation mainly on the GPU ensures fast frame rates. ER