A new method of point cloud boundary extraction based on slice

2021 ◽  
Author(s):  
Haipeng Zhu ◽  
Ming Huang ◽  
Chuanli Zhou
Keyword(s):  
Point Cloud ◽  
New Method ◽  
Boundary Extraction

scholarly journals MXenes as Flow Electrodes for Capacitive Deionization of Wastewater

2020 ◽  
Author(s):  
Kathryn Primerose Drake
Keyword(s):  
Power Spectrum ◽  
Point Cloud ◽  
Vector Fields ◽  
Big Bang ◽  
New Method ◽  
Fundamental Result ◽  
Irregular Domains ◽  
Angular Power Spectrum ◽  
Vector Calculus ◽  
Normal Vectors

This dissertation addresses problems that arise in a diverse group of fields including cosmology, electromagnetism, and graphic design. While these topics may seem disparate, they share a commonality in their need for fast and accurate algorithms which can handle large datasets collected on irregular domains. An important issue in cosmology is the calculation of the angular power spectrum of the cosmic microwave background (CMB) radiation. CMB photons offer a direct insight into the early stages of the universe's development and give the strongest evidence for the Big Bang theory to date. The Hierarchical Equal Area isoLatitude Pixelation (HEALPix) grid is used by cosmologists to collect CMB data and store it as points on the sphere. HEALPix also refers to the software package that analyzes CMB maps and calculates their angular power spectrums. Refined analysis of the CMB angular power spectrum can lead to revolutionary developments in understanding the curvature of the universe, dark matter density, and the nature of dark energy. In the first paper, we present a new method for performing spherical harmonic analysis for HEALPix data, which is a vital component for computing the CMB angular power spectrum. Using numerical experiments, we demonstrate that the new method provides better accuracy and a higher convergence rate when compared to the current methods on synthetic data. This paper is presented in Chapter 2. The problem of constructing smooth approximants to divergence-free (div-free) and curl-free vector fields and/or their potentials based only on discrete samples arises in science applications like fluid dynamics and electromagnetism. It is often necessary that the vector approximants preserve the div-free or curl-free properties of the field. Div/curl-free radial basis functions (RBFs) have traditionally been utilized for constructing these vector approximants, but their global nature can make them computationally expensive and impractical. In the second paper, we develop a technique for bypassing this issue that combines div/curl-free RBFs in a partition of unity (PUM) framework, where one solves for local approximants over subsets of the global samples and then blends them together to form a div-free or curl-free global approximant. This method can be used to approximate vector fields and their scalar potentials on the sphere and in irregular domains in ℝ2 and ℝ3. We present error estimates and demonstrate the effectiveness of the method on several test problems. This paper is presented in Chapter 3. The issue of reconstructing implicit surfaces from oriented point clouds has applications in computer aided design, medical imaging, and remote sensing. Utilizing the technique from the second paper, we introduce a novel approach to this problem by exploiting a fundamental result from vector calculus. In our method, deemed CFPU, we interpolate the normal vectors of the point cloud with a curl-free RBF-PUM interpolant and extract a potential of the reconstructed vector field. The zero-level surface of this potential approximates the implicit surface of the point cloud. Benefits of this method include its ability to represent local sharp features, handle noise in the normal vectors, and even exactly interpolate a point cloud. We demonstrate in the third paper that our method converges for known surfaces and also show how it performs on various surfaces found in the literature. This paper is presented in Chapter 4.

An Automatic Designing Method for Apparel

2011 ◽  
Vol 88-89 ◽  
pp. 175-179
Author(s):  
Xiao Gang Wang ◽  
Qin Zheng ◽  
Xin Zhan Li
Keyword(s):  
Point Cloud ◽  
Science Research ◽  
Mathematic Model ◽  
New Method ◽  
Scanning System ◽  
Body Scanning ◽  
3D Shape ◽  
Vertical Sections ◽  
Set Up ◽  
Designing Method

In this article we discuss a new method for describing the 3D shape of woman warm jacket and set up its mathematic model, which is by dint of body scanning technology. Telmat scanning system scanned samples. The scanning point cloud were analyzed in horizontal and vertical sections. Outlines of vertical sections were described and mathematic models were set up. The result helped to prognosticate the shape of woman warm jacket. A new describing method for 3D shape is discussed. And it opens our mind to utilize body-scanning technology for deeper science research.

scholarly journals A New Method for UAV Lidar Precision Testing Used for the Evaluation of an Affordable DJI ZENMUSE L1 Scanner

2021 ◽  
Vol 13 (23) ◽  
pp. 4811
Author(s):  
Rudolf Urban ◽  
Martin Štroner ◽  
Lenka Línková
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Point Cloud ◽  
Reference Points ◽  
New Method ◽  
Color Information ◽  
Dense Point ◽  
Aerial Vehicle ◽  
Systematic Shift ◽  
Precision Testing ◽  
Better Than

Lately, affordable unmanned aerial vehicle (UAV)-lidar systems have started to appear on the market, highlighting the need for methods facilitating proper verification of their accuracy. However, the dense point cloud produced by such systems makes the identification of individual points that could be used as reference points difficult. In this paper, we propose such a method utilizing accurately georeferenced targets covered with high-reflectivity foil, which can be easily extracted from the cloud; their centers can be determined and used for the calculation of the systematic shift of the lidar point cloud. Subsequently, the lidar point cloud is cleaned of such systematic shift and compared with a dense SfM point cloud, thus yielding the residual accuracy. We successfully applied this method to the evaluation of an affordable DJI ZENMUSE L1 scanner mounted on the UAV DJI Matrice 300 and found that the accuracies of this system (3.5 cm in all directions after removal of the global georeferencing error) are better than manufacturer-declared values (10/5 cm horizontal/vertical). However, evaluation of the color information revealed a relatively high (approx. 0.2 m) systematic shift.

Virtual Modelling of Prehistoric Sites and Artefacts by Automatic Point-Cloud Surveys

2011 ◽  
pp. 201-217
Author(s):  
Mercedes Farjas ◽  
Francisco J. García-Lázaro ◽  
Julio Zancajo ◽  
Teresa Mostaza ◽  
Nieves Quesada
Keyword(s):  
Initial Data ◽  
Research Group ◽  
Point Cloud ◽  
Laser Scanner ◽  
New Method ◽  
Surface Model ◽  
Digital Surface Model ◽  
Automatic Data ◽  
Operational Costs ◽  
New Methodologies

This chapter presents laser scanner systems as a new method of automatic data acquisition for use in archaeological research. The operation of the equipment is briefly described and results are presented from its application in two Spanish archaelogical sites: Abrigo de Buendía (Cuenca), Atapuerca (Burgos). Together with these systems, point cloud measuring photogrammetric methods are revised. Photogrammetry has been widely used in heritage documentation and in no way is to be relegated by the new scanning techniques. Instead, Photogrammetry upgrades its methods by applying digital approaches so that it becomes competitive in both, operational costs and results. Nevertheless, Photogrammetry and laser scanner systems should be regarded as complementary rather than competing techniques. To illustrate photogrammetric methods their application to generate the Digital Surface Model of an epigraph is described. The authors’ research group endeavours to combine teaching and research in its different fields of activity. Initial data are acquired in project-based teaching situations and international seminars or other activities. Students thus have the opportunity to become familiar with new methodologies while collecting material for analytical studies.

Triangulation-Based Point Cloud Data Processing Technology Research and Application

2014 ◽  
Vol 610 ◽  
pp. 729-733
Author(s):  
Ke He Wu ◽  
Wen Chao Cui ◽  
Bo Hao Cheng ◽  
Qian Yuan Zhang
Keyword(s):  
Data Processing ◽  
Data Storage ◽  
Point Cloud ◽  
Extraction Process ◽  
Programming Algorithm ◽  
Point Cloud Data ◽  
Boundary Extraction ◽  
Processing Technologies ◽  
Cloud Data ◽  
Cloud Data Processing

With the "Digital Earth" concept being put forward, people are starting to focus on geospatial information technology. Traditional manual building modeling process is gradually eliminated by history due to cumbersome and inefficient work. With massive data storage and processing technologies emerging and improving, people begin to explore building point cloud data measured by laser radar technology and to use point cloud data processing software for further building boundary extraction. In the model boundary extraction process, the use of prototype with the model fit is a good, clear and easy programming algorithm and triangulation algorithm.

A New Method for Segmenting Individual Trees from the Lidar Point Cloud

2012 ◽  
Vol 78 (1) ◽  
pp. 75-84 ◽  
Author(s):  
Wenkai Li ◽  
Qinghua Guo ◽  
Marek K. Jakubowski ◽  
Maggi Kelly
Keyword(s):  
Point Cloud ◽  
New Method ◽  
Individual Trees
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