scholarly journals Automatic, Multiview, Coplanar Extraction for CityGML Building Model Texture Mapping

2021 ◽  
Vol 14 (1) ◽  
pp. 50
Author(s):  
Haiqing He ◽  
Jing Yu ◽  
Penggen Cheng ◽  
Yuqian Wang ◽  
Yufeng Zhu ◽  
...  
Keyword(s):  
Texture Mapping ◽  
3D Models ◽  
Building Model ◽  
Texture Information ◽  
Building Models ◽  
Photogrammetric Method ◽  
Data Source ◽  
Single Data Source ◽  
Single Data ◽  
Point Line

Most 3D CityGML building models in street-view maps (e.g., Google, Baidu) lack texture information, which is generally used to reconstruct real-scene 3D models by photogrammetric techniques, such as unmanned aerial vehicle (UAV) mapping. However, due to its simplified building model and inaccurate location information, the commonly used photogrammetric method using a single data source cannot satisfy the requirement of texture mapping for the CityGML building model. Furthermore, a single data source usually suffers from several problems, such as object occlusion. We proposed a novel approach to achieve CityGML building model texture mapping by multiview coplanar extraction from UAV remotely sensed or terrestrial images to alleviate these problems. We utilized a deep convolutional neural network to filter out object occlusion (e.g., pedestrians, vehicles, and trees) and obtain building-texture distribution. Point-line-based features are extracted to characterize multiview coplanar textures in 2D space under the constraint of a homography matrix, and geometric topology is subsequently conducted to optimize the boundary of textures by using a strategy combining Hough-transform and iterative least-squares methods. Experimental results show that the proposed approach enables texture mapping for building façades to use 2D terrestrial images without the requirement of exterior orientation information; that is, different from the photogrammetric method, a collinear equation is not an essential part to capture texture information. In addition, the proposed approach can significantly eliminate blurred and distorted textures of building models, so it is suitable for automatic and rapid texture updates.

Event detection of different English data sources based on transfer learning

2021 ◽  
pp. 1-11
Author(s):  
Yanan Huang ◽  
Yuji Miao ◽  
Zhenjing Da
Keyword(s):  
Transfer Learning ◽  
Event Detection ◽  
Visual Analysis ◽  
Learning Algorithm ◽  
Data Sources ◽  
Data Set ◽  
Data Source ◽  
Single Data Source ◽  
The Difference ◽  
Single Data

The methods of multi-modal English event detection under a single data source and isomorphic event detection of different English data sources based on transfer learning still need to be improved. In order to improve the efficiency of English and data source time detection, based on the transfer learning algorithm, this paper proposes multi-modal event detection under a single data source and isomorphic event detection based on transfer learning for different data sources. Moreover, by stacking multiple classification models, this paper makes each feature merge with each other, and conducts confrontation training through the difference between the two classifiers to further make the distribution of different source data similar. In addition, in order to verify the algorithm proposed in this paper, a multi-source English event detection data set is collected through a data collection method. Finally, this paper uses the data set to verify the method proposed in this paper and compare it with the current most mainstream transfer learning methods. Through experimental analysis, convergence analysis, visual analysis and parameter evaluation, the effectiveness of the algorithm proposed in this paper is demonstrated.

scholarly journals MASHUP SCHEME DESIGN OF MAP TILES USING LIGHTWEIGHT OPEN SOURCE WEBGIS PLATFORM

2018 ◽  
Vol XLII-3 ◽  
pp. 565-571
Author(s):  
T. Hu ◽  
J. Fan ◽  
H. He ◽  
L. Qin ◽  
G. Li
Keyword(s):  
Coordinate System ◽  
Low Cost ◽  
Image Data ◽  
Source Image ◽  
Scheme Design ◽  
Paper Cover ◽  
Data Source ◽  
Single Data Source ◽  
Single Data ◽  
Loading Scheme

To address the difficulty involved when using existing commercial Geographic Information System platforms to integrate multi-source image data fusion, this research proposes the loading of multi-source local tile data based on CesiumJS and examines the tile data organization mechanisms and spatial reference differences of the CesiumJS platform, as well as various tile data sources, such as Google maps, Map World, and Bing maps. Two types of tile data loading schemes have been designed for the mashup of tiles, the single data source loading scheme and the multi-data source loading scheme. The multi-sources of digital map tiles used in this paper cover two different but mainstream spatial references, the WGS84 coordinate system and the Web Mercator coordinate system. According to the experimental results, the single data source loading scheme and the multi-data source loading scheme with the same spatial coordinate system showed favorable visualization effects; however, the multi-data source loading scheme was prone to lead to tile image deformation when loading multi-source tile data with different spatial references. The resulting method provides a low cost and highly flexible solution for small and medium-scale GIS programs and has a certain potential for practical application values. The problem of deformation during the transition of different spatial references is an important topic for further research.

scholarly journals Size-Adaptive Texture Atlas Generation and Remapping for 3D Urban Building Models

2021 ◽  
Vol 10 (12) ◽  
pp. 798
Author(s):  
Xuequan Zhang ◽  
Wei Liu ◽  
Bing Liu ◽  
Xin Zhao ◽  
Zihe Hu
Keyword(s):  
Large Scale ◽  
Texture Mapping ◽  
Graphics Hardware ◽  
High Fidelity ◽  
Blank Space ◽  
Web Based ◽  
Vertex Number ◽  
Building Model ◽  
Building Models ◽  
Atlas Method

A high-fidelity 3D urban building model requires large quantities of detailed textures, which can be non-tiled or tiled ones. The fast loading and rendering of these models remain challenges in web-based large-scale 3D city visualization. The traditional texture atlas methods compress all the textures of a model into one atlas, which needs extra blank space, and the size of the atlas is uncontrollable. This paper introduces a size-adaptive texture atlas method that can pack all the textures of a model without losing accuracy and increasing extra storage space. Our method includes two major steps: texture atlas generation and texture atlas remapping. First, all the textures of a model are classified into non-tiled and tiled ones. The maximum supported size of the texture is acquired from the graphics hardware card, and all the textures are packed into one or more atlases. Then, the texture atlases are remapped onto the geometric meshes. For the triangle with the original non-tiled texture, new texture coordinates in the texture atlases can be calculated directly. However, as for the triangle with the original tiled texture, it is clipped into many unit triangles to apply texture mapping. Although the method increases the mesh vertex number, the increased geometric vertices have much less impact on the rendering efficiency compared with the method of increasing the texture space. The experiment results show that our method can significantly improve building model rendering efficiency for large-scale 3D city visualization.

scholarly journals Efficient Capacity-Constrained Multicast in RC-Based P2P Networks

10.29007/dhwl ◽  
2019 ◽  
Author(s):  
Koushik Maddali ◽  
Banafsheh Rekabdar ◽  
Swathi Kaluvakuri ◽  
Bidyut Gupta
Keyword(s):  
Residue Class ◽  
P2p Networks ◽  
Multicast Protocol ◽  
Multicast Protocols ◽  
Application Level Multicast ◽  
Data Source ◽  
Single Data Source ◽  
Single Data ◽  
Capacity Constrained ◽  
Better Than

Application level multicast is independent of router infrastructure unlike router-based IP multicast. The existing DHT-based application level multicast protocols work efficiently as long as there is almost no churn; otherwise, their performances start degrading drastically, because DHT – based architecture cannot handle churn effectively. Besides, most of DHT-based multicast protocols consider single data source and do not consider peer heterogeneity. In this work, we have considered an existing non-DHT based P2P architecture, viz., Residue Class based (RC-based) architecture which has already been shown to perform much better than some well-known DHT-based architectures from the viewpoints of speed of unicast communication and churn handling. We have presented a highly efficient capacity-constrained and any source multicast protocol suitable for the RC-based P2P architecture as mentioned above.

Design Modification of Additive Manufacturing Parts Using Texture Information of 3D Model

2019 ◽  
Vol 825 ◽  
pp. 19-30
Author(s):  
Tsung Chien Wu ◽  
Jiing Yih Lai ◽  
Yu Wen Tseng ◽  
Chao Yaug Liao ◽  
Ju Yi Lee
Keyword(s):  
Additive Manufacturing ◽  
3D Model ◽  
Three Dimensional ◽  
Texture Mapping ◽  
3D Models ◽  
Surface Shape ◽  
Design Features ◽  
Design Modification ◽  
Texture Information ◽  
Triangular Model

Additive manufacturing (AM) has been commonly used for the prototyping of three-dimensional (3D) models. The input model of the AM technology is a triangular model representing the surface shape of an object. The design features on a triangular model are generally not clear as the vertices are irregularly distributed. If design modification is necessary, it is difficult to segment and extract the meshes from the model. The objective of this study is to propose a method for extracting the design features on an object model by using the texture information. A 3D color model including a triangular model representing the object shape and a texture map describing the object texture is employed. The 3D model is generated by using a set of object images captured from different views surrounding the object. A texture mapping algorithm is then employed to generate the texture map corresponding to the 3D model. With both meshes and texture displayed in a texture mode, a region extraction technique is employed to extract the design features. All parts separated can then be fabricated with an AM machine, and assembled for checking the feasibility of design modification. Several products are employed to demonstrate the feasibility of the proposed technique.

scholarly journals Comparing interview and trade data in assessing changes in the seahorse Hippocampus spp. trade following CITES listing

Oryx ◽  
2014 ◽  
Vol 50 (1) ◽  
pp. 36-46 ◽  
Author(s):  
Joy T.L. Lam ◽  
Heather J. Koldewey ◽  
Maï Yasué ◽  
Amanda C.J. Vincent
Keyword(s):  
Hong Kong ◽  
Medicinal Uses ◽  
Price Increases ◽  
Local Stakeholders ◽  
Global Impacts ◽  
Data Source ◽  
Single Data Source ◽  
Single Data ◽  
Source Countries ◽  
Government Statistics

AbstractConcerns regarding the sustainability of the seahorse Hippocampus spp. trade led to their listing on CITES Appendix II in 2002, with implementation in 2004. In 2007 we interviewed wholesale traders of seahorses in Hong Kong, China, seeking indications of the effects of the CITES listing on the seahorse trade. We cross-validated traders’ perspectives with government trade statistics (1998–2007) from Hong Kong and Taiwan. We also compared these data with trade statistics for pipefish, which are related species with similar medicinal uses but are not CITES-listed. Both the interviews and government statistics indicated reduced volumes of seahorses traded through Hong Kong, changes in source countries, and price increases post-implementation. Traders suggested that these changes were largely a result of the CITES listing. However, data indicate that other factors such as shifts in domestic policies and local demand may also have affected the trade. By cross-validating the perspectives of local stakeholders with trade statistics in a wildlife trading hub we were able to explore hypotheses on the local and global impacts of CITES. Such approaches are especially important for CITES-listed species because often there is no single data source that is complete and wholly reliable.

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