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C. C V C L. Mosaic-Based 3D Scene Representation and Rendering. Allen Hanson Computer Vision Laboratory Computer Science Department University of Massachusetts Amherst hanson@cs.umass.edu. Zhigang Zhu Visual Computing Lab Department of Computer Science
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C CVC L Mosaic-Based 3D Scene Representation and Rendering Allen Hanson Computer Vision Laboratory Computer Science Department University of Massachusetts Amherst hanson@cs.umass.edu Zhigang Zhu Visual Computing Lab Department of Computer Science City College and Graduate Center City University of New York zhu@cs.ccny.cuny.edu
Some Real World Problems • City/Campus modeling (AFRL, NYSIA) - airborne video: far-view (1000 ft) • Environmental monitoring (NSF) - airborne video of Amazon rain forest: far-view (1000 ft) • Robot Navigation (DARPA, ARO)- ground video: medium range (~100ft) • Under-vehicle inspection (ACT Inc.) - car drives over cameras: near-view (< 8 in) Zhu & Hanson ICIP '05
Objectives • Input: 2D array of cameras • multiple viewpoints; motion parallax • Output: Image-based representation • WFOV, Stereo, Occlusion Rep. Zhu & Hanson ICIP '05
Related Work • 2D mosaics from a pure rotating camera • QuickTime VR, VideoBrush, Microsoft… • Stereo mosaics from off-center rotating camera(s) • two cameras (Huang & Hung 1998) • one camera ( Peleg et al PAMI 01, Shum & Szeliski ICCV99) • Panoramic imaging from a translating camera • Manifold projection (Peleg et al CVPR’97, PAMI2000) • multiple-center-of-projection (Rademacher & Bishop, SigGraph'98) • EPI-based 3D reconstruction (Zhu, XU & Lin, CVPR99) • linear pushbroom camera (R. Gupta & R. Hartley, PAMI 97) • Parallel projection ( Chai & Shum, CVPR’00) • Geo-referenced mosaic • Plane+Parallax+DEM (Kumar, Sawhney, et al , ICPR98, 2000) Zhu & Hanson ICIP '05
Outline • Mosaic Representation • Research Issues • Real Applications • Air, Ground and Under-Vehicle • Summary Zhu & Hanson ICIP '05
Mosaic Representations • Perspective Image • notes: (one viewpoint, occlusion in both forward and backward direction) • Orthogonal Image (Nadir view) • notes: only nadir (or frontal) view - cannot see sides • Images with Oblique Parallel Projection • Notes: multiple parallel - can see everything (generalization of orthogonal image) Zhu & Hanson ICIP '05
O invisible Perspective Images • One viewpoint O • Narrow FOV • Multiple viewing directions Zhu & Hanson ICIP '05
Orthogonal Images • Multiple viewpoints • Wide FOV • One viewing direction -Nadir view • Occlusion invisible invisible Zhu & Hanson ICIP '05
Oblique Parallel Projections • Multiple viewpoints – Wide FOV • Multiple viewing directions • Parallel rays in each image • Various oblique angles: invisible visible invisible visible invisible invisible Nadir ‘Forward’ ‘Backward’ Zhu & Hanson ICIP '05
Multiple parallel-perspective mosaics • Multi-disparity stereo: • Correspondence for 3D reconstruction • Mosaic-based rendering without 3D • View selection and rendering Zhu & Hanson ICIP '05
Stereo Mosaics • Mosaics with two different oblique angles • Parallel projection • Adaptive baseline • Uniform depth resolution Zhu & Hanson ICIP '05
Stereo Mosaics • Mosaics with two different oblique angles • Parallel projection • Adaptive baseline • Uniform depth resolution Zhu & Hanson ICIP '05
Advantages • Various Oblique Parallel Projections • Occlusion representation • Adaptive Baselines • Uniform depth resolution • Large FOV stereo • High quality 3D from stereo mosaics • Image-based rendering without 3D Zhu & Hanson ICIP '05
Main Research Issues • Real-World Problem • Uneven, sparse camera “array” • 6 DOF motion of camera • Two Main Research Issues • Orientation Estimation (see real applications) • GPS, INS, Bundle Adjustment • Parallel Ray Generation • Ray Interpolation - PRISM Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • Regular Camera with arbitrary orientation Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • Regular Camera with perspective projection Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • Cameras with various known orientations Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • Existing parallel rays with oblique angle b Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • Interpolate rays between frames by local match Zhu & Hanson ICIP '05
PRISM: Ray Interpolation - 1D case • … a dense parallel projection with angle b Zhu & Hanson ICIP '05
Computation & Algorithm:distribute the computations in four steps • Geo-Referencing • Motion estimation: sparse tie points distributed in entire frames • Seamless Mosaicing (PRISM) • Process two narrow slices • Stereo Matching • stereo match only in two mosaics with adaptive baselines • 3D Mapping/Visualization • just a coordinate transformation and resampling Zhu & Hanson ICIP '05
Real Applications • Aerial Video Surveillance • Under-Vehicle Inspection Zhu & Hanson ICIP '05
Instrumentation Package on an Airplane Watson Attitude & Heading Reference System Profiling Laser Altimeter Canon XL1 DV camcorders Duct Tape Zhu & Hanson ICIP '05
Objectives • Rapidly create large FOV image mosaics that are • geo-referenced, • with 3D (stereo) viewing and • with all dynamic targets identified • As a light UAV flies over an area Zhu & Hanson ICIP '05
Multiple parallel-perspective mosaics • Multi-disparity stereo: • Correspondence for 3D reconstruction • Mosaic-based rendering without 3D • View selection and rendering Zhu & Hanson ICIP '05
Virtual Fly-Through Digital City/Campus Zhu & Hanson ICIP '05
Real Applications • Aerial Video Surveillance • Under-Vehicle Inspection Zhu & Hanson ICIP '05
Camera Geometry of the UVIS • Car drives over a 1D array of cameras… Zhu & Hanson ICIP '05
Y X • 32 cameras (images) per column – spatial “scan” • Car moves – temporal “scan” 1 Zhu & Hanson ICIP '05
Y X Zhu & Hanson ICIP '05
Y X 1 2 Zhu & Hanson ICIP '05
Y X 1 2 3 Zhu & Hanson ICIP '05
Y X 1 2 3 4 Zhu & Hanson ICIP '05
Y X 1 2 3 4 5 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 9 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 9 10 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 9 10 11 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 9 10 11 12 1 2 3 4 6 5 7 Zhu & Hanson ICIP '05
Y X 1 2 3 4 6 5 7 8 9 10 11 12 1 2 3 4 6 5 7 • 32 cameras (images) per column – spatial “scan” • 48 columns (12 feet)- 4 inch separation in temporal “scan” direction • 1536 virtual cameras (images) with 2D scans • Different viewpoints! Zhu & Hanson ICIP '05
UVIS: A Mosaicing example with 2D scan 1D array of 4 cameras ; car moves First pass: mosaicing along the columns (4 cameras) Second pass: mosaicing in the motion direction Zhu & Hanson ICIP '05
One camera to N stereo mosaics • Very near range view • Distortion removal • Motion estimation • Stereo mosaicing • anomaly detection Zhu & Hanson ICIP '05
UVIS: Dynamic Stereo Mosaics 6 mosaics with changing viewing directions Stereo mosaics: Each pair of 6 mosaics is a stereo pair Dynamic mosaics: Look around objects even without stereo Zhu & Hanson ICIP '05
UVIS: Dynamic Stereo Mosaics 6 mosaics with changing viewing directions Stereo mosaics: Each pair of 6 mosaics is a stereo pair Dynamic mosaics: Look around objects even without stereo Zhu & Hanson ICIP '05
UVIS: Dynamic Stereo Mosaics 6 mosaics with changing viewing directions Stereo mosaics: Each pair of 6 mosaics is a stereo pair Dynamic mosaics: Look around objects even without stereo Zhu & Hanson ICIP '05
UVIS: Dynamic Stereo Mosaics 6 mosaics with changing viewing directions Stereo mosaics: Each pair of 6 mosaics is a stereo pair Dynamic mosaics: Look around objects even without stereo Zhu & Hanson ICIP '05
UVIS: Dynamic Stereo Mosaics 6 mosaics with changing viewing directions Stereo mosaics: Each pair of 6 mosaics is a stereo pair Dynamic mosaics: Look around objects even without stereo Zhu & Hanson ICIP '05
Summary • Stereo Mosaics with Oblique Parallel Projections • Wide FOV • Occlusion Rep. • Stereo pairs • Research Issues • Orientation Estimation • Ray Interpolation ( Interframe match) • 3D reconstruction and Moving Target Detection • Real Applications • Airborne Surveillance • Ground Robot Navigation • Under-Vehicle Inspection Zhu & Hanson ICIP '05