290 likes | 428 Views
SmartBoxes for Interactive Urban Reconstruction. Liangliang Nan 1 , Andrei Sharf 1 , Hao Zhang 2 , Daniel Cohen-Or 3 , Baoquan Chen 1 1 Shenzhen Institutes of Advanced Technology (SIAT), China 2 Simon Fraser University, Canada 3 University of Tel Aviv, Israel. 3D Cities.
E N D
SmartBoxes for Interactive Urban Reconstruction Liangliang Nan1, Andrei Sharf1, Hao Zhang2, Daniel Cohen-Or3, Baoquan Chen1 1 Shenzhen Institutes of Advanced Technology (SIAT), China 2 Simon Fraser University, Canada 3University of Tel Aviv, Israel
3D Cities Virtual Philadelphia Virtual Berlin
Acquisition of Urban Environments Remote Sensing Systems Airborne LIDAR Cameras/videos Auto-mounted LIDAR 3D Digital City
3D LiDAR scanner • Street-level • 60km/h • 180 pitch • [100-300m] range • 100K points/second • 5cm XY accuracy
Imperfect Scans - Occlusions • Point cloud contains holes due to various occlusions (“shadows”)
Imperfect Scans – Angle & Range • Oblique scanning angle • Laser energy attenuation on range
Urban Building Characteristics • Dominant planes • Repetitions, intra symmetry and regularity • Axis-aligned basic primitives
SmartBoxes • Box-up and Smart!
SmartBoxes • Box prior shape fitting • Smart context awareness Data Context Both
Related Work • Procedural modeling of buildings and facades [Wonka2003;Muller2007] • Automatic 3D reconstruction from 2D images [Zisserman2002;Xiao2009;Furukawa2009] • Interactive modeling of architectural structures [Debevec1996;Schindler2003; Xiao2008;Sinha2008;Jiang2009] • Primitive fitting to data [Gal2007;Schnabel 2009]
Preprocessing • Automatic detection of planes and edges assuming dominant orthogonal axes • RANSAC planes • Line sweep edges
Snapping a Box • 2D rubber band ROI • Collect planes, edges, corners • Find the best fitting box using data fitting force D(B,P)
Data fitting D(B,P) snap • Data fitting force Facet Edge Data quality (Confidence + Density) Distance
Grouping • Simple SmartBox Compound SmartBox • Align to remove gaps and intersections • cluster and align close to co-linear edges
Drag-and-drop context C(Bi-1, Bi) • The context of Bi Interval Alignment Scale ••• Bi Bi-3 Bi-2 Bi-1 Context
Drag-and-drop context C(Bi-1, Bi) • The context of Bi • Interval term ••• Bi Bi-3 Bi-2 Bi-1
Drag-and-drop context C(Bi-1, Bi) • The context of Bi • Alignment term ••• Bi-3 Bi-2 Bi-1 Bi
Drag-and-drop context C(Bi-1, Bi) • The context of Bi • Scale term ••• Bi-3 Bi-2 Bi-1 Bi Bi
Discrete objective minimization • Find linear transformation T(excluding rotation) to minimize: Data fitting force Contextual force
Discrete objective minimization • Find linear transformation T(excluding rotation) to minimize: Data fitting force Contextual force ••• Bi-3 Bi-2 Bi-1
Habitat 67 (Montreal, Canada) The Crooked House (Sopot, Poland) Manchester Civil Justice Centre (Manchester, UK)