The generation of reality-based 3D models of archeological sites is the future of representing existing ancient structures. Such approach requires substantial economic and logistical costs which limit this application...The generation of reality-based 3D models of archeological sites is the future of representing existing ancient structures. Such approach requires substantial economic and logistical costs which limit this application. In this context, this paper presents the use of photogrammetric workflow, based on Structure from Motion techniques (SfM) to derive 3D metric information from Structure-and-Motion images. The interdisciplinary 3D modeling framework consists of fusion of multi resolution images from both overlapped low-altitude aerial and multi-view terrestrial imagery. The acquisition of aerial photographs survey was based on archived oblique aerial stereo pair photos acquired from the Aerial Photographic Archive for Archaeology in the Middle East (APAAME) project, while terrestrial of close range photos covering the castle walls has been acquired using portable camera. Camera calibration and orientation were carried out by VisualSFM, CMPMVS (Multi-View Reconstruction) and SURE (Photogrammetric Surface Reconstruction from Imagery) software. The resulted cloud points were processed using cloud Compare, MeshLab, Agisoft, and Skethup Softwares. A complete 3D digital geometric recording of the site was accomplished based on dense 3D point clouds with realistic metric accuracy and photorealistic performance to meet all the surveying and archaeological needs. The final Ajloun castle’s digital model geometry was added as a 3D building layer on Google Earth.展开更多
A new scheme for femur shape recovery from volumetric images using deformable models was proposed. First, prior 3 D deformable femur models are created as templates using point distribution models technology. Second, ...A new scheme for femur shape recovery from volumetric images using deformable models was proposed. First, prior 3 D deformable femur models are created as templates using point distribution models technology. Second, active contour models are employed to segment the magnetic resonance imaging (MRI) volumetric images of the tibial and femoral joints and the deformable models are initialized based on the segmentation results. Finally, the objective function is minimized to give the optimal results constraining the surface of shapes.展开更多
The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions a...The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.展开更多
Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geome...Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geometric area to sub-cellular dimensions leads to a significant increase in impedance thus affecting its recording capabilities.We report a breakthrough ultra-microelectrodes platform by leveraging the outstanding surface-to-volume ratio of nanowire-templated out-of-plane synthesized three-dimensional fuzzy graphene(NT-3DFG).The enormous surface area of NT-3DFG leads to 140-fold reduction in electrode impedance compared to bare Au microelectrodes,thus enabling scaling down the geometric size by 625-fold to ca.2µm×2µm.The out-of-plane morphology of NT-3DFG leads to a tight seal with the cell membrane thus enabling recording of electrical signals with high signal-to-noise ratio(SNR)of>6.This work highlights the possibility to push the limits of the conventional MEA technology to enable electrophysiological investigation at sub-cellular level without the need of any surface coatings.This presented approach would greatly impact our basic understanding of signal transduction within a single cell as well as complex cellular assemblies.展开更多
in this poper a novel data-and rule-driven system for 3D scene description and segmentation inan unknown environment is presented.This system generatss hierachies of features that correspond tostructural elements such...in this poper a novel data-and rule-driven system for 3D scene description and segmentation inan unknown environment is presented.This system generatss hierachies of features that correspond tostructural elements such as boundaries and shape classes of individual object as well as relationshipsbetween objects.It is implemented as an added high-level component to an existing low-level binocularvision system[1]. Based on a pair of matched stereo images produced by that system,3D segmentation is firstperformed to group object boundary data into several edge-sets,each of which is believed to belong to aparticular object.Then gross features of each object are extracted and stored in an object recbrd.The finalstructural description of the scene is accomplished with information in the object record,a set of rules and arule implementor. The System is designed to handle partially occluded objects of different shapes and sizeson the 2D imager.Experimental results have shown its success in computing both object and structurallevel descriptions of common man-made objects.展开更多
Cadastral surveying plays an important role in defining legal boundaries of land and property.The current practice for recording cadastral survey data mainly relies on 2D digital or analog documents.This practice is e...Cadastral surveying plays an important role in defining legal boundaries of land and property.The current practice for recording cadastral survey data mainly relies on 2D digital or analog documents.This practice is efficient for simple land parcels but can be challenged in complex building developments.To address the issues stemmed from 2D methods of representing cadastral survey data,3D spatial information models can be considered as a viable solution for managing cadastral survey data.Building Information Modeling(BIM)enables colsslaborative 3D management of the design,construction,and operation of buildings.There have been extensive studies conducted to investigate the connectivity between BIM and 3D cadaster.Most of these studies focus on managing legal information,such as ownership boundaries and attributes,in BIM-based environments.However,there is limited investigation on how survey-ing measurements can be mapped into BIM.In this study,the proposed method for integrating the cadastral survey data into the BIM environment includes identifying cadastral survey requirements,using BIM entities relevant to cadastral survey data,enrichment of a BIM proto-type,and evaluation of the prototype.The major contribution of this study is to demonstrate the storage of cadastral survey data such as survey marks and traverse lines in the BIM environment.Therefore,this research contributes to the further enrichment of BIM with incorporating data elements related to cadastral surveying practices.It is confirmed that current BIM-based tools provide restricted capabilities for explicit management and visualiza-tion of cadastral survey data.This limitation can be addressed in the future enhancements of BIM in terms of supporting important elements for cadastral survey data.展开更多
The paper presents innovative informatics methods for creating virtual technical heritage replicas, which are of significant scientific and practical importance not only to researchers but to the public in general. By...The paper presents innovative informatics methods for creating virtual technical heritage replicas, which are of significant scientific and practical importance not only to researchers but to the public in general. By performing 3D modeling and animation of aircrafts, spaceships, architectural-engineering buildings, and other technical objects, the process of teaming is achieved while promoting the preservation of the replicas for future generations. Modem approaches based on the wide usage of computer technologies attract a greater number of young people to explore the history of science and technology and renew their interest in the field of mechanical engineering.展开更多
文摘The generation of reality-based 3D models of archeological sites is the future of representing existing ancient structures. Such approach requires substantial economic and logistical costs which limit this application. In this context, this paper presents the use of photogrammetric workflow, based on Structure from Motion techniques (SfM) to derive 3D metric information from Structure-and-Motion images. The interdisciplinary 3D modeling framework consists of fusion of multi resolution images from both overlapped low-altitude aerial and multi-view terrestrial imagery. The acquisition of aerial photographs survey was based on archived oblique aerial stereo pair photos acquired from the Aerial Photographic Archive for Archaeology in the Middle East (APAAME) project, while terrestrial of close range photos covering the castle walls has been acquired using portable camera. Camera calibration and orientation were carried out by VisualSFM, CMPMVS (Multi-View Reconstruction) and SURE (Photogrammetric Surface Reconstruction from Imagery) software. The resulted cloud points were processed using cloud Compare, MeshLab, Agisoft, and Skethup Softwares. A complete 3D digital geometric recording of the site was accomplished based on dense 3D point clouds with realistic metric accuracy and photorealistic performance to meet all the surveying and archaeological needs. The final Ajloun castle’s digital model geometry was added as a 3D building layer on Google Earth.
基金National Natural Science Foundation ofChina!( 69772 0 0 2 )
文摘A new scheme for femur shape recovery from volumetric images using deformable models was proposed. First, prior 3 D deformable femur models are created as templates using point distribution models technology. Second, active contour models are employed to segment the magnetic resonance imaging (MRI) volumetric images of the tibial and femoral joints and the deformable models are initialized based on the segmentation results. Finally, the objective function is minimized to give the optimal results constraining the surface of shapes.
基金the Key Project of Joint Funds of Yalongjiang River Development of the National Natural Science Foundation of China (No. 50539050)
文摘The appearance of 3D laser scanning technology is one of the most important technology revolutions in surveying and mapping field. It can be widely used in many interrelated fields, such as engineering constructions and 3D measurements, owing to its prominent characteristics of the high efficiency and high precision. At present its application is still in the initial state, and it is quite rarely used in China, especially in geotechnical engineering and geological engineering fields. Starting with a general introduction of 3D laser scanning technology, this article studies how to apply the technology to high rock slope investigations. By way of a case study, principles and methods of quick slope documentation and occurrence measurement of discontinuities are discussed and analyzed. Analysis results show that the application of 3D laser scanning technology to geotechnical and geological engineering has a great prospect and value.
基金T.C.-K.acknowledges funding support from the National Science Foundation under Award No.CBET1552833 and the Office of Naval Research under Award No.N000141712368.J.B.and A.W F.acknowledge financial support from the Dowd Fellowship from the College of Engineering at Carnegie Mellon University.L.M.and F.S.acknowledge Valentina Mollo for ssthe preparation of SEM/FIB samples.We also acknowledge support from the Department of Materials Science and Engineering Materials Characterization Facility(MCF-677785).
文摘Microelectrode arrays(MEAs)have enabled investigation of cellular networks at sub-millisecond temporal resolution.However,current MEAs are limited by the large electrode footprint since reducing the electrode’s geometric area to sub-cellular dimensions leads to a significant increase in impedance thus affecting its recording capabilities.We report a breakthrough ultra-microelectrodes platform by leveraging the outstanding surface-to-volume ratio of nanowire-templated out-of-plane synthesized three-dimensional fuzzy graphene(NT-3DFG).The enormous surface area of NT-3DFG leads to 140-fold reduction in electrode impedance compared to bare Au microelectrodes,thus enabling scaling down the geometric size by 625-fold to ca.2µm×2µm.The out-of-plane morphology of NT-3DFG leads to a tight seal with the cell membrane thus enabling recording of electrical signals with high signal-to-noise ratio(SNR)of>6.This work highlights the possibility to push the limits of the conventional MEA technology to enable electrophysiological investigation at sub-cellular level without the need of any surface coatings.This presented approach would greatly impact our basic understanding of signal transduction within a single cell as well as complex cellular assemblies.
文摘in this poper a novel data-and rule-driven system for 3D scene description and segmentation inan unknown environment is presented.This system generatss hierachies of features that correspond tostructural elements such as boundaries and shape classes of individual object as well as relationshipsbetween objects.It is implemented as an added high-level component to an existing low-level binocularvision system[1]. Based on a pair of matched stereo images produced by that system,3D segmentation is firstperformed to group object boundary data into several edge-sets,each of which is believed to belong to aparticular object.Then gross features of each object are extracted and stored in an object recbrd.The finalstructural description of the scene is accomplished with information in the object record,a set of rules and arule implementor. The System is designed to handle partially occluded objects of different shapes and sizeson the 2D imager.Experimental results have shown its success in computing both object and structurallevel descriptions of common man-made objects.
文摘虚拟现实(Virtual Reality,VR)的兴起使得三维音频技术得到进一步的应用。VR中三维音频的回放一般采用基于双耳的方式,目前VR中应用较多的三维音频技术有基于物理声场重建和球谐分解的Ambisonics技术,基于自然双耳录音(Binaural recording)的技术,以及基于头相关传递函数(Head Related Transfer Function,HRTF)重建的技术。此外在考虑环境混响效果的场景下还需要双耳房间脉冲响应(Binaural Room Impulse Response,BRIR)技术。介绍了VR中现有的三维音频技术和市场上的主要应用,介绍了VR音频从采集,编码传输到渲染回放整个过程中的主流相关技术,最后对VR三维音频的发展进行了展望。
基金This work is supported by the Australian Research Council[grant number LP160100292].
文摘Cadastral surveying plays an important role in defining legal boundaries of land and property.The current practice for recording cadastral survey data mainly relies on 2D digital or analog documents.This practice is efficient for simple land parcels but can be challenged in complex building developments.To address the issues stemmed from 2D methods of representing cadastral survey data,3D spatial information models can be considered as a viable solution for managing cadastral survey data.Building Information Modeling(BIM)enables colsslaborative 3D management of the design,construction,and operation of buildings.There have been extensive studies conducted to investigate the connectivity between BIM and 3D cadaster.Most of these studies focus on managing legal information,such as ownership boundaries and attributes,in BIM-based environments.However,there is limited investigation on how survey-ing measurements can be mapped into BIM.In this study,the proposed method for integrating the cadastral survey data into the BIM environment includes identifying cadastral survey requirements,using BIM entities relevant to cadastral survey data,enrichment of a BIM proto-type,and evaluation of the prototype.The major contribution of this study is to demonstrate the storage of cadastral survey data such as survey marks and traverse lines in the BIM environment.Therefore,this research contributes to the further enrichment of BIM with incorporating data elements related to cadastral surveying practices.It is confirmed that current BIM-based tools provide restricted capabilities for explicit management and visualiza-tion of cadastral survey data.This limitation can be addressed in the future enhancements of BIM in terms of supporting important elements for cadastral survey data.
文摘The paper presents innovative informatics methods for creating virtual technical heritage replicas, which are of significant scientific and practical importance not only to researchers but to the public in general. By performing 3D modeling and animation of aircrafts, spaceships, architectural-engineering buildings, and other technical objects, the process of teaming is achieved while promoting the preservation of the replicas for future generations. Modem approaches based on the wide usage of computer technologies attract a greater number of young people to explore the history of science and technology and renew their interest in the field of mechanical engineering.
