Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage

Beijing, China

Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage

Beijing, China
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Ren P.,Beijing Normal University | Ren P.,Engineering Research Center for Virtual Reality Application | Ren P.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Fan Y.,Beijing Normal University | And 14 more authors.
Computers and Graphics (Pergamon) | Year: 2017

The existing three-dimensional (3D) object layout methods are focused mainly on indoor scenes and they are limited for outdoor applications. In this study, we propose a data-driven method for outdoor scene modeling by using fast retrieval and automatic optimization layout techniques. Unlike the current methods, we first employ an improved manifold ranking algorithm in the sketch-based 3D model retrieval stage, which achieves higher accuracy. Next, according to the particular properties of outdoor architectures, specialized constraints are then proposed to define an energy function, which meets both the functional and aesthetic requirements. Finally, we cast the auto-arrangement as a combinatorial optimization problem, which we solve using an optimization algorithm. In contrast to the earlier version of this method, which was presented at Cyberworlds 2016, this extended version combines simulated annealing and particle swarm optimization algorithms, which have the advantages of rapid convergence and avoiding becoming trapped by local minima. Our experimental results demonstrate that the proposed method is more intuitive and effective for modeling 3D scenes, and can be employed in the actual development of game scenes. © 2017 Elsevier Ltd


Hu S.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Zhou M.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Shui W.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Wu Z.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2015

Ball Pivoting algorithm is mainly used for surface reconstruction of point cloud data, the algorithm starts from a seed triangle, the ball along the seed triangle a side of rotation until the ball is exposed to a point and the edge and the composition of a triangle. The main disadvantage of this algorithm is that when the point cloud data is not uniform when the ball in the rolling process does not contact the point, and therefore will have a hole. A non-uniform point cloud data for improved reconstruction of the Ball Pivoting algorithm of the original point cloud data was proposed to construct k-d tree, allowing searching area algorithm time efficiency; variable radius search algorithm could make the algorithm deal with non-uniform point cloud data and did not produce hole, putting forward the more being a searching area algorithm, to optimize the topology structure of the grid. The experimental results show that the algorithm is efficient and cannot generate the holes and the topological structure of the triangle mesh is better than the Ball Pivoting algorithm. © 2015, The Editorial Board of Journal of System Simulation. All right reserved.


Zhao S.,Beijing Normal University | Zhao S.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Zhou M.,Beijing Normal University | Zhou M.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | And 5 more authors.
Neurocomputing | Year: 2015

The precise segmentation of cerebral vessels is essential for detecting cerebral diseases. This work proposed a novel method for automatic extraction of blood vessels. The proposed framework includes three steps: (a) projection from 3D volume to 2D plane: in order to make up the small percentage vessels occupy in each slice and to avoid overlapping between vessels, the volume dataset is projected from different directions; (b) extraction on 2D plane: a new energy model is proposed using phase-field and statistical information which is based on the Allen-Cahn equation with a double well potential and statistical data fitting terms. The segmentation is based on curve evolution. This model is effective in extracting blood vessels with low contrast, multi-branch structure and intensity inhomogeneity from projection images; (c) projecting back from 2D plane to 3D volume: the pixels segmented from previous step will be projected back into the volume dataset, and the corresponding voxels in the volume will be reserved to construct the blood vessels in three-dimensional space. Experimental results illustrate that the performance of the methods is better than existing techniques. © 2015 Elsevier B.V.


Deng Q.,Beijing Normal University | Zhou M.,Beijing Normal University | Zhou M.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Wu Z.,Beijing Normal University | And 7 more authors.
Forensic Science International | Year: 2016

Craniofacial reconstruction recreates a facial outlook from the cranium based on the relationship between the face and the skull to assist identification. But craniofacial structures are very complex, and this relationship is not the same in different craniofacial regions. Several regional methods have recently been proposed, these methods segmented the face and skull into regions, and the relationship of each region is then learned independently, after that, facial regions for a given skull are estimated and finally glued together to generate a face. Most of these regional methods use vertex coordinates to represent the regions, and they define a uniform coordinate system for all of the regions. Consequently, the inconsistence in the positions of regions between different individuals is not eliminated before learning the relationships between the face and skull regions, and this reduces the accuracy of the craniofacial reconstruction. In order to solve this problem, an improved regional method is proposed in this paper involving two types of coordinate adjustments. One is the global coordinate adjustment performed on the skulls and faces with the purpose to eliminate the inconsistence of position and pose of the heads; the other is the local coordinate adjustment performed on the skull and face regions with the purpose to eliminate the inconsistence of position of these regions. After these two coordinate adjustments, partial least squares regression (PLSR) is used to estimate the relationship between the face region and the skull region. In order to obtain a more accurate reconstruction, a new fusion strategy is also proposed in the paper to maintain the reconstructed feature regions when gluing the facial regions together. This is based on the observation that the feature regions usually have less reconstruction errors compared to rest of the face. The results demonstrate that the coordinate adjustments and the new fusion strategy can significantly improve the craniofacial reconstructions. © 2015 Elsevier Ireland Ltd.


Yang G.-L.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Zhou M.-Q.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Wu Z.-K.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Shui W.-Y.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Wang K.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage
Xitong Fangzhen Xuebao / Journal of System Simulation | Year: 2014

A robust non-blind watermarking algorithm for 3D mesh of cultural heritage in digital museum was proposed based on spectral analysis to protect the copyright. The algorithm employed spectral analysis to modify mesh shapes and color in their transformed domain and the energy of watermark would diffuse all over the mesh, and in result it attributed global robustness to algorithm. The algorithm employed mesh partitioning to improve computational efficiency and the global robustness especially mesh resection. The algorithm employed watermarked mesh standardization based on TPS(thin-plate spine) transformation to improve the robustness of remesh and affine transformation. The algorithm employed QR-code to code and decode the information of watermark. The distortion correction technology of QR-code improved algorithm global robustness. Experiment shows that the visual quality of watermarked mesh is good. Experiment also shows that algorithm is robust to affine transformation, random noise, mesh smoothing, resmesh, and partial resection.


Yang A.Y.,CAS National Astronomical Observatories | Yang A.Y.,University of Chinese Academy of Sciences | Tian W.W.,CAS National Astronomical Observatories | Tian W.W.,University of Chinese Academy of Sciences | And 7 more authors.
Astrophysical Journal, Supplement Series | Year: 2016

We construct H i absorption spectra for 18 planetary nebulae (PNs) and their background sources using data from the International Galactic Plane Survey. We estimate the kinematic distances of these PNs, among which 15 objects' kinematic distances are obtained for the first time. The distance uncertainties of 13 PNs range from 10% to 50%, which is a significant improvement with uncertainties of a factor of two or three smaller than most previous distance measurements. We confirm that PN G030.2-00.1 is not a PN because of its large distance found here. © 2016. The American Astronomical Society. All rights reserved..


Wang J.,Beijing Normal University | Wang J.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | Zhao S.,Beijing Normal University | Zhao S.,Beijing Key Laboratory of Digital Preservation and Virtual Reality for Cultural Heritage | And 8 more authors.
Computational and Mathematical Methods in Medicine | Year: 2016

Cerebral vessel segmentation is essential and helpful for the clinical diagnosis and the related research. However, automatic segmentation of brain vessels remains challenging because of the variable vessel shape and high complex of vessel geometry. This study proposes a new active contour model (ACM) implemented by the level-set method for segmenting vessels from TOF-MRA data. The energy function of the new model, combining both region intensity and boundary information, is composed of two region terms, one boundary term and one penalty term. The global threshold representing the lower gray boundary of the target object by maximum intensity projection (MIP) is defined in the first-region term, and it is used to guide the segmentation of the thick vessels. In the second term, a dynamic intensity threshold is employed to extract the tiny vessels. The boundary term is used to drive the contours to evolve towards the boundaries with high gradients. The penalty term is used to avoid reinitialization of the level-set function. Experimental results on 10 clinical brain data sets demonstrate that our method is not only able to achieve better Dice Similarity Coefficient than the global threshold based method and localized hybrid level-set method but also able to extract whole cerebral vessel trees, including the thin vessels. © 2016 Jiaxin Wang et al.

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