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Real-Time Image Mosaicing. --Research Project for 15-869, Nov 29, 1999 Li Zhang. Image Mosaicing. Stitching together images taken from different viewpoints seamlessly Representation: cylindrical, spherical, and perspective panoramas. Problem Statement.
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Real-Time Image Mosaicing --Research Project for 15-869, Nov 29, 1999 Li Zhang
Image Mosaicing • Stitching together images taken from different viewpoints seamlessly • Representation: cylindrical, spherical, and perspective panoramas
Problem Statement • Given two images I0 and I1 of a scene, find a transform T that minimizes
Special cases • If the scene is planar, and I0 and I1are taken from different viewpoints with different orientation, • If the scene is arbitrary, and I0 and I1are taken from same viewpoint with different orientation, T is a planar perspective transform M
My work • Given two images I0 and I1 of a scene, find a transform M that minimizes • Search M interactively in real-time
Algorithm Details(1) • Given I0, I1 and current M,we iteratively update M using • We wish D to minimize
Algorithm Details(2) • We warp I1 into I1’ such that • We instead wish D to minimize
Acceleration Details(1) • We find d by solving a least-square minimization problem with following acceleration techniques: • Approximate the Jacobian as
Acceleration Details(2) • Warp I1’ from I1using hardware-accelerated texture mapping; • Perform minimization hierarchically using OpenGL Mipmaps.
Results(1) • Real images of University Center Mural
Results(2) • Full view panorama of UC Mural
Summary(1) • Good features: • Users can interactively create image mosaics in real-time • The transform is locally optimized
Summary(2) • 8-parameter transform sometimes get stuck in local minimum • The size of image is limited by frame buffer
Reference • R. Szeliski and H.-Y. Shum. Creating full view panoramic image mosaics and texture-mapped models. Computer Graphics (SIGGRAPH'97), pages 251-258, August 1997.