scholarly journals Automatic Reconstruction of Building Façade Model from Photogrammetric Mesh Model

2021 ◽  
Vol 13 (19) ◽  
pp. 3801
Author(s):  
Yunsheng Zhang ◽  
Chi Zhang ◽  
Siyang Chen ◽  
Xueye Chen
Keyword(s):  
Three Dimensional ◽  
Iteration Process ◽  
Polygonal Mesh ◽  
Topological Relationship ◽  
Mesh Model ◽  
Building Facade ◽  
Bottom To Top ◽  
Relationship Of ◽  
Contour Tree ◽  
Mesh Models

Three-dimensional (3D) building façade model reconstruction is of great significance in urban applications and real-world visualization. This paper presents a newly developed method for automatically generating a 3D regular building façade model from the photogrammetric mesh model. To this end, the contour is tracked on irregular triangulation, and then the local contour tree method based on the topological relationship is employed to represent the topological structure of the photogrammetric mesh model. Subsequently, the segmented contour groups are found by analyzing the topological relationship of the contours, and the original mesh model is divided into various components from bottom to top through the iteration process. After that, each component is iteratively and robustly abstracted into cuboids. Finally, the parameters of each cuboid are adjusted to be close to the original mesh model, and a lightweight polygonal mesh model is taken from the adjusted cuboid. Typical buildings and a whole scene of photogrammetric mesh models are exploited to assess the proposed method quantitatively and qualitatively. The obtained results reveal that the proposed method can derive a regular façade model from a photogrammetric mesh model with a certain accuracy.

Using a Four-Dimensional Mesh Model to Represent a Tool Motion Trajectory in Five-Axis Machining

2014 ◽  
Vol 8 (3) ◽  
pp. 437-444 ◽  
Author(s):  
Hirotaka Kameyama ◽  
◽  
Ikuru Otomo ◽  
Masahiko Onosato ◽  
Fumiki Tanaka ◽  
...  
Keyword(s):  
Cutting Tools ◽  
Three Dimensional ◽  
3D Models ◽  
Temporal Changes ◽  
Cutting Process ◽  
Machining Processes ◽  
Mesh Model ◽  
Spatio Temporal ◽  
Five Axis ◽  
Mesh Models

In the field of machining processes, three-Dimensional (3D) models are commonly used to simulate the motions of cutting tools and workpieces. However, it is difficult for 3D models to represent spatio-temporal changes in their shapes continuously and to a high degree of accuracy. The objective of this study is to represent the 5-axis cutting process of workpiece transformation explicitly using a spatio-temporal model, the “four-Dimensional (4D) mesh model.” Every 4D mesh model is defined with bounding tetrahedral cells, and can continuously represent spatio-temporal changes of shape, position and orientation. In this study, the five-axis cutting process is described using accumulated volumes of 4D mesh models. Accumulated volumes are total volumes determined by spaces through which the object has passed. The use of accumulated volumes enables us to record tool-swept volumes and material removal shapes. First, this report introduces a 4D mesh model and the development of a 4D mesh modeling system. Next, a method of representing accumulated volumes as 4D mesh models is proposed. Generated 4D models are observed as 3D models by means of cross-section extraction.

Calculation of Areas of Cultural Relics Surface Defects Based on the Triangular Mesh Model

2012 ◽  
Vol 446-449 ◽  
pp. 3452-3456
Author(s):  
Xiao Qing Zhang ◽  
Miao Le Hou ◽  
Guang Zhu ◽  
Yun Gang Hu
Keyword(s):  
Surface Defects ◽  
Three Dimensional ◽  
Triangular Mesh ◽  
Scientific Data ◽  
Topological Relationship ◽  
Mesh Model ◽  
Triangular Mesh Model ◽  
Topological Characteristics ◽  
Novel Algorithm ◽  
Cultural Relics

In order to solve the problem that need exact and scientific data in checking and restoring cultural relics, this paper presents a novel algorithm that statistics defect areas of cultural relics by calculating holes area in the in triangular mesh models.First, build the topological relationship between triangles, vertices and edges and extract boundary using boundary property of triangular mesh. Next, the holes bounding edges are linked in sequence into holes polygon. Finally, distinguish holes boundary and model exterior boundary by means of triangular mesh topological characteristics and the areas of three-dimensional holes polygon are calculated to statistics defect areas of cultural relics through the method of coordinate. Through experiments, it proved that this algorithm was correctly and reasonable.

A comparative study and combined application of RSM and ANN in adsorptive removal of diuron using biomass ashes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sunil K. Deokar ◽  
Nachiket A. Gokhale ◽  
Sachin A. Mandavgane
Keyword(s):  
Three Dimensional ◽  
Current Approach ◽  
Coefficient Of Determination ◽  
Ann Model ◽  
Operational Parameters ◽  
Initial Concentration ◽  
Combined Application ◽  
Artificial Neural Network Ann ◽  
Relationship Of ◽  
Biomass Ashes

Abstract Biomass ashes like rice husk ash (RHA), bagasse fly ash (BFA), were used for aqueous phase removal of a pesticide, diuron. Response surface methodology (RSM) and artificial neural network (ANN) were successfully applied to estimate and optimize the conditions for the maximum diuron adsorption using biomass ashes. The effect of operational parameters such as initial concentration (10–30 mg/L); contact time (0.93–16.07 h) and adsorbent dosage (20–308 mg) on adsorption were studied using central composite design (CCD) matrix. Same design was also employed to gain a training set for ANN. The maximum diuron removal of 88.95 and 99.78% was obtained at initial concentration of 15 mg/L, time of 12 h, RHA dosage of 250 mg and at initial concentration of 14 mg/L, time of 13 h, BFA dosage of 60 mg respectively. Estimation of coefficient of determination (R 2) and mean errors obtained for ANN and RSM (R 2 RHA = 0.976, R 2 BFA = 0.943) proved ANN (R 2 RHA = 0.997, R 2 BFA = 0.982) fits better. By employing RSM coupled with ANN model, the qualitative and quantitative activity relationship of experimental data was visualized in three dimensional spaces. The current approach will be instrumental in providing quick preliminary estimations in process and product development.

A Research on the Morphology and Composition of Flocs (Part 1: Floc Breaage Disregarded)

2013 ◽  
Vol 726-731 ◽  
pp. 1566-1572 ◽  
Author(s):  
Shi Qiang Ding ◽  
Qing Na Li ◽  
Xin Rong Pang ◽  
Ji Run Xu
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
New Classification ◽  
Suspension Viscosity ◽  
Primary Particles ◽  
Long Time ◽  
Relationship Of ◽  
The Relationship ◽  
Three Dimensional Space ◽  
Floc Breakage

The characteristics of flocs aggregated in flocculation have been paid more and more attention for a long time. In this paper, a new classification and analyses method dealing with the flocs is developed. The flocs formed after flocculation is divided into four kinds, including the left primary particles, linear flocs with all component particles in a line, planar flocs with all component particles on a plane and volumetric flocs with all component particles in a three-dimensional space. By analyzing the formation approaches of different kind of flocs regardless of the floc breakage, the number of every kind of floc is analyzed to be related with the suspension concentration mathematically. After comparing the different items in the models describing the relationship of floc number and concentration, a series of simplified expressions are presented. Lastly, a mathematical equation relating the measurable suspension viscosity with the numbers of different flocs is obtained.

Geometric simulation for warp-knitted tubular bandages with the mesh model

2021 ◽  
pp. 004051752110138
Author(s):  
Haisang Liu ◽  
Gaoming Jiang ◽  
Zhijia Dong
Keyword(s):  
Programming Languages ◽  
Three Dimensional ◽  
3D Mesh ◽  
Mesh Model ◽  
Matrix Operations ◽  
Computer Aided ◽  
Spatial Geometry ◽  
3D Mesh Model ◽  
Coordinate Mapping ◽  
Geometric Simulation

The purpose of this paper is to geometrically simulate warp-knitted medical tubular bandages with a computer-aided simulator. A flat mesh model is established according to unfolded fabric considering the knitting characteristics of double-needle bed warp-knitted tubular fabrics. Moreover, a 3D (three-dimensional) mesh model corresponding to the actual product shape is created. To better describe the spatial geometry of stitches, eight-point models are introduced, and stitches are generated with the flat mesh model. Founded on matrix operations, the stitch position in the 3D mesh model is determined through coordinate mapping. Various stitch paths are rendered in computer programming languages C# and JavaScript to conduct simulations. Warp-knitted medical tubular bandages with a large number of shapes are effectively modeled.

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