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Records: 1 - 20 of 1,177 - Pages: 
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Integration of Image Data for Refining Building Boundaries Derived from Point Clouds : Volume Xl-3, Issue 1 (11/08/2014)

By: D. Schneider; N. Hetti Arachchige; S. N. Perera

Description: Institute of Photogrammetry and Remote Sensing, Technische Universität Dresden, Helmholtz Straße 10, 01069 Dresden, Germany. Geometrically and topologically correct 3D building models are required to satisfy with new demands such as 3D cadastre, map updating, and decision making. More attention on building reconstruction has been paid using Airborne Laser Scanning (ALS) point cloud data. The planimetric accuracy of roof outlines, including step-edges is questionable in building models derived from only point clouds. This paper presents a new approach for the detection of accurate building boundaries by merging point clouds acquired by ALS and aerial photographs. It comprises two major parts: reconstruction of initial roof models from point clouds only, and refinement of their boundaries. A shortest closed circle (graph) analysis method is employed to generate building models in the first step. Having the advantages of high reliability, this method provides reconstruction without prior knowledge of primitive building types even when complex height jumps and various types of building roof are available. The accurat...

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An Automated Method for 3D Roof Outline Generation and Regularization in Airbone Laser Scanner Data : Volume I-3, Issue 1 (20/07/2012)

By: H.-g. Maas; H. A. Nalani; S. N. Perera

Description: Institute of Photogrammetry and Remote Sensing, Technische Universität Dresden, Helmholtz Straße 10, 01069 Dresden, Germany. In this paper, an automatic approach for the generation and regularization of 3D roof boundaries in Airborne Laser scanner data is presented. The workflow is commenced by segmentation of the point clouds. A classification step and a rule based roof extraction step are followed the planar segmentation. Refinement on roof extraction is performed in order to minimize the effect due to urban vegetation. Boundary points of the connected roof planes are extracted and fitted series of straight line segments. Each line is then regularized with respect to the dominant building orientation. We introduce the usage of cycle graphs for the best use of topological information. Ridge-lines and step-edges are basically extracted to recognise correct topological relationships among the roof faces. Inner roof corners are geometrically fitted based on the closed cycle graphs. Outer boundary is reconstructed using the same concept but with the outer most cycle graph. In here, union of the sub cycles is taken. Interme...

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Delineation of Building Footprints from High Resolution Satellite Stereo Imagery Using Image Matching and a Gis Database : Volume Xl-1/W1, Issue 1 (30/04/2013)

By: C. Heipke; G. R. Dini; K. Jacobsen

Description: Institute of Photogrammetry and GeoInformation (IPI), Leibniz Universität Hannover, Nienburger Str. 1, 30167 Hannover, Germany. In this paper, a workflow is proposed to delineate building footprints from high resolution satellite stereo images through integration of a Digital Surface Model (DSM), 3D edge matching technique and GIS building polygons. First, Digital Surface Models (DSM) and a normalised DSM are derived by traditional image matching. Three different removal masks are employed to reduce the effects of matching errors, roads and vegetation. We then compare all resulting blobs with the GIS 2D building layer. For blobs without a partner in the database, building outlines are extracted based on 3D edge matching. To do so, edges on epipolar images are first detected individually on each image using the Canny operator. After removing short edges and extracting straight lines, we find the best corresponding lines using various constraints. Finally, the topological relationship of the derived 3D edges is employed to reconstruct the shape of the building and the building footprints using a box-fitting approac...

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New Types of Stable Nonlinear Whistler Waveguides : Volume 9, Issue 2 (30/11/-0001)

By: Yu. A. Zaliznyak; T. A. Davydova; A. I. Yakimenko

Description: Plasma Theory Department, Institute for Nuclear Research, Nauki Ave. 47, Kiev 03680, Ukraine. The stationary self-focusing of whistler waves with frequencies near half of the electron-cyclotron frequency in the ionospheric plasma is considered in the framework of a two-dimensional generalized nonlinear Schrödinger equation including fourth-order dispersion effects and nonlinearity saturation. New types of soliton-like (with zero topological charge) and vortex-like nonlinear waveguides are found, and their stability confirmed both analytically and numerically....

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An Approach to Develop 3D Geo-dbms Topological Operators by Re-using Existing 2D Operators : Volume Ii-2/W1, Issue 1 (13/09/2013)

By: S. Zlatanova; D. Xu

Description: Jaffalaan 9, 2628 BX, Delft, the Netherlands. Database systems are continuously extending their capabilities to store, process and analyse 3D data. Topological relationships which describe the interaction of objects in space is one of the important spatial issues. However, spatial operators for 3D objects are still insufficient. In this paper we present the development of a new 3D topological function to distinguish intersections of 3D planar polygons. The development uses existing 2D functions in the DBMS and two geometric transformations (rotation and projection). This function is tested for a real dataset to detect overlapping 3D city objects. The paper presents the algorithms and analyses the challenges. Suggestions for improvements of the current algorithm as well as possible extensions to handle more 3D topological cases are discussed at the end....

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Sequential Modelling of Building Rooftops by Integrating Airborne Lidar Data and Optical Imagery: Preliminary Results : Volume Ii-3/W1, Issue 1 (16/05/2013)

By: C. Armenakis; Y. Jwa; G. Sohn; J. Jung

Description: GeoICT lab, Department of Earth and Space Science and Engineering, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada. This paper presents a sequential rooftop modelling method to refine initial rooftop models derived from airborne LiDAR data by integrating it with linear cues retrieved from single imagery. A cue integration between two datasets is facilitated by creating new topological features connecting between the initial model and image lines, with which new model hypotheses (variances to the initial model) are produced. We adopt Minimum Description Length (MDL) principle for competing the model candidates and selecting the optimal model by considering the balanced trade-off between the model closeness and the model complexity. Our preliminary results, combined with the Vaihingen data provided by ISPRS WGIII/4 demonstrate the image-driven modelling cues can compensate the limitations posed by LiDAR data in rooftop modelling....

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Edge-based Registration for Airborne Imagery and Lidar Data : Volume Xxxix-b3, Issue 1 (31/07/2012)

By: C. Y. Lo; L. C. Chen

Description: Center for Space and Remote Sensing, National Central University, Taiwan. Aerial imagery and LIDAR points are two important data sources for building reconstruction in a geospatial area. Aerial imagery implies building contours with planimetric features; LIDAR data explicitly represent building geometries using three-dimensional discrete point clouds. Data integration may take advantage of merits from two data sources in building reconstruction and change detection. However, heterogeneous data may contain a relative displacement because of different sensors and the capture time. To reduce this displacement, data registration should be an essential step. Therefore, this investigation proposes an edge-based approach to register these two data sets in three parts: (1) data preprocessing; (2) feature detection; and (3) data registration. The first step rasterizes laser point clouds into a pseudo-grid digital surface model (PDSM), which describes the relief with the original elevation information. The second step implements topological analyses to detect image edges and three-dimensional structure lines from the aeri...

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Automated Reconstruction of Walls from Airborne Lidar Data for Complete 3D Building Modelling : Volume Xxxix-b3, Issue 1 (24/07/2012)

By: M. Awrangjeb; C. Zhang; C. S. Fraser; Y. He

Description: Cooperative Research Centre for Spatial Information, Department of Infrastructure Engineering University of Melbourne, VIC 3010, Australia. Automated 3D building model generation continues to attract research interests in photogrammetry and computer vision. Airborne Light Detection and Ranging (LIDAR) data with increasing point density and accuracy has been recognized as a valuable source for automated 3D building reconstruction. While considerable achievements have been made in roof extraction, limited research has been carried out in modelling and reconstruction of walls, which constitute important components of a full building model. Low point density and irregular point distribution of LIDAR observations on vertical walls render this task complex. This paper develops a novel approach for wall reconstruction from airborne LIDAR data. The developed method commences with point cloud segmentation using a region growing approach. Seed points for planar segments are selected through principle component analysis, and points in the neighbourhood are collected and examined to form planar segments. Afterwards, segment-...

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Plane Trigonometry

By: Dresden, Arnold, B. 1882
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Papers upon analysis situs; Volume: 6

By: Rutt, Norman Eby; American Mathematical Society. Bulletin; American Mathematical Society. Transaction; Moore, Robert Lee

Supplemental catalog subcollection information: American Libraries Collection; American University Library Collection; Rare book preservation notes: Due to the deteriorated condition of this book, there were limitations with the digital preservation of th...

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Natural Trigonometric Functions : To Seven Decimal Places For Every Ten Seconds Of Arc

By: Ives, Howard Chapin, 1878-1944
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S-Rings on Compact Transformation Groups

By: Wood, G. V.; University of Warwick. Mathematics Institute

Bibliography: leaf 12

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S-Rings on Compact Groups

By: Wood, G. V.; University of Warwick. Mathematics Institute

Bibliography: leaf 15

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The Isomorphism and Thermal Properties of the Feldspars

By: Allen, Eugene Thomas, 1864; Iddings, Joseph Paxson, 1857-1920; Day, Arthur Louis, 1869

Pt. I. Thermal study / by Arthur L. Day and E.T. Allen. -- Pt. II. Optical study / by J.P. Iddings ; with an introduction by George F. Becker

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The Isomorphism and Thermal Properties of the Feldspars

By: Day, Arthur Louis, 1869-1960; Iddings, Joseph Paxson, 1857-1920; Becker, George Ferdinand, 1847-1919; Allen, Eugene Thomas, 1864-1964
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Papers upon analysis situs; Volume: 3

By: Rutt, Norman Eby; American Mathematical Society. Bulletin; American Mathematical Society. Transaction; Moore, Robert Lee

Supplemental catalog subcollection information: American Libraries Collection; American University Library Collection; Rare book preservation notes: Due to the deteriorated condition of this book, there were limitations with the digital preservation of th...

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Plane Trigonometry

By: Dresden, Arnold, B. 1882

Topology ; NATURAL SCIENCES ; Mathematics

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The Isomorphism and Thermal Properties of the Feldspars

By: Day, Arthur Louis, 1869-1960; Iddings, Joseph Paxson, 1857-1920; Becker, George Ferdinand, 1847-1919; Allen, Eugene Thomas, 1864-1964

Pt. I. Thermal study / Arthur L. Day and E.T. Allen -- Pt. II. Optical study / J.P. Iddings ; with an introduction by George F. Becker

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Topological Semivector Spaces; Convexity and Fixed Point Theory

By: Prakash, Prem; Sertel, Murat R

MIT Libraries

Bibliography: leaves 34-35 ;

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Lunar lander conceptual design

By: Lee, Joo Ahn; Choi, Andrew; Dillman, Robert; Griffin, Sean J. ; Hanneman, Susan; Mamplata, Caesar; Stanton, Edwar; Carini, John

Supplemental catalog subcollection information: NASA Publication Collection; Astrophysics and Technical Documents; A conceptual design is presented of a Lunar Lander, which can be the primary vehicle to transport the equipment necessary to establish a sur...

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