Remarkable progress in the development of modeling methods for indoor spaces has been made in recent years with a focus on the reconstruction of complex environments, such as multi-room and multi-level buildings. Exis...
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Remarkable progress in the development of modeling methods for indoor spaces has been made in recent years with a focus on the reconstruction of complex environments, such as multi-room and multi-level buildings. Existing methods represent indoor structure models as a combination of several sub-spaces, which are constructed by room segmentation or horizontal slicing approach that divide the multi-room or multi-level building environments into several segments. In this study, we propose an automatic reconstruction method of multi-level indoor spaces with unique models, including inter-room and inter-floor connections from point cloud and trajectory. We construct structural points from registered point cloud and extract piece-wise planar segments from the structural points. Then, a three-dimensional space decomposition is conducted and water-tight meshes are generated with energy minimization using graph cut algorithm. The data term of the energy function is expressed as a difference in visibility between each decomposed space and trajectory. The proposed method allows modeling of indoor spaces in complex environments, such as multi-room, room-less, and multi-level buildings. The performance of the proposed approach is evaluated for seven indoor space datasets.
The pulse function (PF) is a technique based on procedural preprocessing system to generate a computerized virtual photo of the facade with in a fixed size square(Alizadehashrafi et al., 2009, Musliman et al., 2010). ...
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ISBN:
(纸本)9781629935201
The pulse function (PF) is a technique based on procedural preprocessing system to generate a computerized virtual photo of the facade with in a fixed size square(Alizadehashrafi et al., 2009, Musliman et al., 2010). dynamic Pulse Function (dPF) is an enhanced version of PF which can create the final photo, proportional to real geometry. This can avoiddistortion while projecting the computerized photo on the generated3d model(Alizadehashrafi and Rahman, 2013). The challenging issue that might be handled for having 3d model in Lod3 rather than LOd2, is the final aim that have been achieved in this paper. In the technique baseddPF the geometries of the windows anddoors are saved in an XML file schema which does not have any connections with the 3d model in Lod2 and CityGML format. In this research the parameters of dynamic Pulse Functions are utilized via Ruby programming language in SketchUp Trimble to generate (exact position anddeepness) the windows anddoors automatically in Lod3 based on the same concept of dPF. The advantage of this technique is automatic generation of huge number of similar geometries e.g. windows by utilizing parameters of dPF along with defining entities and window layers. In case of converting the SKP file to CityGML via FME software or CityGML plugins the 3d model contains the semantic database about the entities and window layers which can connect the CityGML to MySQL(Alizadehashrafi and Baig, 2014). The concept behinddPF, is to use logical operations to project the texture on the background image which is dynamically proportional to real geometry. The process of projection is based on two vertical and horizontal dynamic pulses starting from upper-left corner of the background wall in down and right directions respectively based on image coordinate system. The logical one/zero on the intersections of two vertical and horizontal dynamic pulses projects/does not project the texture on the background image. It is possible to define prio
The segmentation of point clouds is an important aspect of automated processing tasks such as semantic extraction. However, the sparsity and non-uniformity of the point clouds gathered by the popular 3d mobile LidAR d...
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The segmentation of point clouds is an important aspect of automated processing tasks such as semantic extraction. However, the sparsity and non-uniformity of the point clouds gathered by the popular 3d mobile LidAR devices pose many challenges for existing segmentation methods. To improve the segmentation results of point clouds from mobile LidAR devices, we propose an optimized segmentation method based on Scanline Continuity Constraint (SLCC) in this work. Unlike conventional scanline-based segmentation methods, SLCC clusters scanlines using the continuity constraints in terms of the distance as well as the direction of two consecutive points. In addition, scanline clusters are agglomerated not only into primitive geometrical shapes but also irregular shapes. Another downside to existing segmentation methods is that they are not capable of incremental processing. This causes unnecessary memory and time consumption for applications that require frame-wise segmentation or when new point clouds are added. In order to address this, we propose an incremental scheme-the Incremental Recursive Segmentation (IRIS), that can be easily applied to any segmentation method. IRIS is achieved by combining the segments of newly added point clouds and the previously segmented results. Furthermore, as an example application, we construct a processing pipeline consisting of plane fitting and surface reconstruction using the segmentation results. Finally, we evaluate the proposed methods on three datasets acquired from a handheld Velodyne HdL-32E LidAR device. The experimental results verify the efficiency of IRIS for any segmentation method and the advantages of SLCC for processing mobile LidAR data.
This paper presents an approach for 3dmodeling of beams in structures using laser scanning after identifying several deficiencies in current methodologies of model extrusion. It highlights the errors due to the actua...
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This paper presents an approach for 3dmodeling of beams in structures using laser scanning after identifying several deficiencies in current methodologies of model extrusion. It highlights the errors due to the actual deformation of beams, which does not correspond with the idealized straight line. To avoid these errors, a novel algorithm has been developed. This algorithm performed the segmentation of a beam point cloud by means of a 2.5d approach based on digital image processing. Thereafter, a polynomial surface fitting of flange points is performed in order to model the deformations of beams based on the combined effects of bending moment and torsions deflections. The tool automatically compares the idealized straight plane of flanges with a 3d curved surface reconstructed from the scanneddata and analyzes whether it is above the maximum limits established by structural codes. Finally, the end product is a 3d model of the deformed beam. (C) 2015 Elsevier Ltd. All rights reserved.
The demand of 3d city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3d city map, virtual city tourism invi...
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ISBN:
(纸本)9781628413083
The demand of 3d city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3d city map, virtual city tourism inviting future visitors to a virtual city walkthrough and others. We proposed a simple method for reconstructing a 3d urban landscape from airborne LidAR point clouddata. The automatic reconstruction method of a 3d urban landscape was implemented by the integration of all connected regions, which were extracted and extruded from the altitude mask images. These mask images were generated from the gray scale LidAR image by the altitude threshold ranges. In this study we demonstrated successfully in the case of Kanazawa city center scene by applying the proposed method to the airborne LidAR point clouddata.
The contribution of this paper is twofold: (1) it presents an automatic 3d modeling technique and (2) it advances a procedure for its metrological evaluation in the context of a medical application, the 3dmodeling of...
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The contribution of this paper is twofold: (1) it presents an automatic 3d modeling technique and (2) it advances a procedure for its metrological evaluation in the context of a medical application, the 3dmodeling of dental plaster casts. The motivation for this work is the creation of a "virtual gypsotheque" where cumbersome dental plaster casts can be replaced by numerical 3d models, thereby alleviating storage and access problems and allowing dentists and orthodontists the use of novel and unprecedented software tools for their medical evaluations. modeling free-form surfaces of anatomical interest is an intriguing mixture of open issues concerning 3dmodeling, geometrical metrology. and medicine. Of general interest is both the fact that a widespread use of 3dmodeling in non-engineering applications requires automatic procedures of the kind presented in this work and the adopted validation paradigm for free-form surfaces, rather useful for practical purposes. In this latter respect, the metrological analysis we advance is the first seminal attempt in the field of 3dmodeling and can be readily extended to contexts other than the medical one discussed in this paper. (C) 2006 IPEM. Published by Elsevier Ltd. All rights reserved.
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