scholarly journals Mapping Nonsquare and Unevenly Spaced 2-D SLDV Data of an Aircraft Fuselage by Using Spatial DFT-IDFT Techniques

1996 ◽  
Vol 3 (2) ◽  
pp. 135-140 ◽  
Author(s):  
William Xinzuo Li ◽  
Larry D. Mitchell ◽  
Min-Fu Lu ◽  
Michael L. Neumann
Keyword(s):  
Laser Scanning ◽  
Mapping Technique ◽  
Data Mapping ◽  
Point Distribution ◽  
Aircraft Fuselage ◽  
Sense Data ◽  
Data Points ◽  
Rectangular Grids ◽  
Data Point ◽  
Minimum Distortion

The scanning laser Doppler vibrometry (SLDV) technique provides velocities of a structure at 2-dimensional (2-D) angularly evenly spaced (in the laser scanning sense) data points. This causes an unevenly spaced data point distribution on the surface of the test structure. In many cases evenly spaced data point distribution with square or rectangular grids is highly desirable. In this study the SLDV velocity data of a partial surface area of an aircraft fuselage were mapped to truly spatial evenly spaced coordinates by using the spatial DFT-IDFT technique with minimum distortion. This 2-D data mapping technique certainly is not limited to the fuselage, hut can he very useful for many other 3-D structures.

scholarly journals QOS ANALYSIS OF WIRELESS NETWORKS BASED ON LOW MOBILITY PROTOCOL

2019 ◽  
Vol 01 (02) ◽  
pp. 126-138
Author(s):  
Bindhu V
Keyword(s):  
Quality Of Service ◽  
Performance Measure ◽  
Point Problem ◽  
Delivery Ratio ◽  
Mobile Wireless ◽  
Data Points ◽  
Data Point ◽  
Hidden Data ◽  
Existing Structure

The decision on the possible trails to be taken by an information that is to be transmitted from a data point to its destined point enact to have more significance on the performance measure of the transmission. The mobile wireless network is also one such network whose quality of service are determined from the ways the trails are entrenched. This wireless adhoc network that is independent of the previously existing structure forms a topology that undergoes spontaneous changes with the closely existing data points or devices. This type of networks are well suited for many adverse situation and environment, but certain attributes of the wireless adhoc such as insubstantial bandwidth, more over head in paths , hidden data point problem, energy restraints, motility interfered routing make them visage difficulties in having a proper routing, empowering MANET to achieve lesser quality in the service provided. So this paper quality of service analysis for the MANET using high power low mobility protocol ensures a routing path entrenchment between highly energetic with diminished motility data points to improvise the quality of service. The QoS analysis is done based on the delay, throughput and the packet delivery ratio to measure its performance.

scholarly journals An Efficient Filtering Approach for Removing Outdoor Point Cloud Data of Manhattan-World Buildings

2021 ◽  
Vol 13 (19) ◽  
pp. 3796
Author(s):  
Lei Fan ◽  
Yuanzhi Cai
Keyword(s):  
Point Cloud ◽  
Indoor Environment ◽  
Laser Scanning ◽  
Point Cloud Data ◽  
Hole Filling ◽  
Cloud Data ◽  
Indoor Space ◽  
Wide Range ◽  
Data Points ◽  
Filtering Approach

Laser scanning is a popular means of acquiring the indoor scene data of buildings for a wide range of applications concerning indoor environment. During data acquisition, unwanted data points beyond the indoor space of interest can also be recorded due to the presence of openings, such as windows and doors on walls. For better visualization and further modeling, it is beneficial to filter out those data, which is often achieved manually in practice. To automate this process, an efficient image-based filtering approach was explored in this research. In this approach, a binary mask image was created and updated through mathematical morphology operations, hole filling and connectively analysis. The final mask obtained was used to remove the data points located outside the indoor space of interest. The application of the approach to several point cloud datasets considered confirms its ability to effectively keep the data points in the indoor space of interest with an average precision of 99.50%. The application cases also demonstrate the computational efficiency (0.53 s, at most) of the approach proposed.

Sphericity Evaluation Based on Minimum Circumscribed Sphere Method

2012 ◽  
Vol 433-440 ◽  
pp. 3146-3151 ◽  
Author(s):  
Fan Wu Meng ◽  
Chun Guang Xu ◽  
Juan Hao ◽  
Ding Guo Xiao
Keyword(s):  
Convex Hull ◽  
Early Stage ◽  
Measured Data ◽  
Efficient Approach ◽  
Critical Data ◽  
Material Condition ◽  
Data Points ◽  
Point Set ◽  
Data Point

The search of sphericity evaluation is a time-consuming work. The minimum circumscribed sphere (MCS) is suitable for the sphere with the maximum material condition. An algorithm of sphericity evaluation based on the MCS is introduced. The MCS of a measured data point set is determined by a small number of critical data points according to geometric criteria. The vertices of the convex hull are the candidates of these critical data points. Two theorems are developed to solve the sphericity evaluation problems. The validated results show that the proposed strategy offers an effective way to identify the critical data points at the early stage of computation and gives an efficient approach to solve the sphericity problems.

scholarly journals LiDAR based urban vegetation mapping as a basis of green infrastructure planning

2020 ◽  
Vol 171 ◽  
pp. 02008
Author(s):  
Krzysztof Pyszny ◽  
Mariusz Sojka ◽  
Rafał Wróżyński
Keyword(s):  
Green Infrastructure ◽  
Urban Areas ◽  
Laser Scanning ◽  
Noise Pollution ◽  
Point Clouds ◽  
Data Mapping ◽  
Vegetation Density ◽  
Island Effect ◽  
Detailed Assessment ◽  
The City

Planning green infrastructure in the cities is a challenging task for planners and city managers. Developing multifunctional green space systems provide many benefits including: increasing water retention, mitigating urban heat island effect, microclimate regulation, reducing air, water and noise pollution and conservation biodiversity. The greenery in the city also have an impact on human health. The paper presents the possibilities of using LiDAR data mapping vegetation density in urban areas on the example of Gorzów Wielkopolski (Poland). Maps made as a result of processing the point clouds obtained from airborne laser scanning represents the most accurate, comprehensive and detailed assessment of Gorzów Wielkopolski vegetation cover to date and establishes the baseline for greenery governance and planning of green infrastructure in the city.

The Research of Data Points Quality Assessment Method in Reverse Engineering

2009 ◽  
Vol 419-420 ◽  
pp. 445-448 ◽  
Author(s):  
Jun Ting Cheng ◽  
Wei Ling Zhao ◽  
Can Zhao ◽  
Xue Dong Xie
Keyword(s):  
Reverse Engineering ◽  
Data Quality ◽  
Quality Assessment ◽  
Assessment Method ◽  
Measured Data ◽  
Quality Data ◽  
Data Quality Assessment ◽  
Quality Assessment Method ◽  
Data Points ◽  
Data Point

In the field of reverse engineering, data quality assessment is a very important work in the detection, the result of data quality assessment will directly or indirectly affect the detection and the following manufacturing process quality. Data quality assessment can be used in the camera calibration, the model and model reconstruction comparison, and so on. In this paper, on the basis of the existing method of calculating each point error, and multipurpose use of average and standard error and some other concepts of mathematical statistics, and then improve a novel and simple calculating error method. This method is applicable to many groups of one-to-one ideal data and the measured data comparison, and it can be more intuitive to reflect the error of overall data, as well as the error distribution, and it can be more efficient to determine the measured data is reasonable or not. In this paper, the data point quality which is collected in the reverse engineering is assessed, and it can see that the method which is proposed in this article has some advantages in the data point quality assessment field.

scholarly journals Parameterization Method on B-Spline Curve

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
H. Haron ◽  
A. Rehman ◽  
D. I. S. Adi ◽  
S. P. Lim ◽  
T. Saba
Keyword(s):  
Computer Model ◽  
Basis Function ◽  
Real Object ◽  
Reconstruction Process ◽  
B Spline ◽  
Parameterization Method ◽  
Spline Basis ◽  
Data Points ◽  
Data Point ◽  
2D And 3D

The use of computer graphics in many areas allows a real object to be transformed into a three-dimensional computer model (3D) by developing tools to improve the visualization of two-dimensional (2D) and 3D data from series of data point. The tools involved the representation of 2D and 3D primitive entities and parameterization method using B-spline interpolation. However, there is no parameterization method which can handle all types of data points such as collinear data points and large distance of two consecutive data points. Therefore, this paper presents a new parameterization method that is able to solve those drawbacks by visualizing the 2D primitive entity of scanned data point of a real object and construct 3D computer model. The new method has improved a hybrid method by introducing exponential parameterization method in the beginning of the reconstruction process, followed by computing B-spline basis function to find maximum value of the function. The improvement includes solving a linear system of the B-spline basis function using numerical method. Improper selection of the parameterization method may lead to the singularity matrix of the system linear equations. The experimental result on different datasets show that the proposed method performs better in constructing the collinear and two consecutive data points compared to few parameterization methods.

LEARNING DECISION REGIONS BASED ON ADAPTIVE ELLIPSOIDS

2014 ◽  
Vol 22 (01) ◽  
pp. 41-73 ◽  
Author(s):  
LEEHTER YAO ◽  
KUEI-SUNG WENG
Keyword(s):  
Genetic Algorithm ◽  
Effective Index ◽  
Cluster Validity ◽  
Fuzzy Classifier ◽  
Learning Capability ◽  
Point Distribution ◽  
Underlying Distribution ◽  
Data Points ◽  
Approximate Decision ◽  
Validity Measure

A fuzzy classifier using multiple ellipsoids to approximate decision regions for classification is designed in this paper. To learn the sizes and orientations of ellipsoids, an algorithm called evolutionary ellipsoidal classification algorithm (EECA) that integrates the genetic algorithm (GA) with the Gustafson-Kessel algorithm (GKA) is proposed. Within EECA the GA is employed to learn the size of every ellipsoid. With the size of every ellipsoid encoded and intelligently estimated in the GA chromosome, GKA is utilized to learn the corresponding ellipsoid. GKA is able to adapt the distance norm to the underlying distribution of the prototype data points for an assigned ellipsoid size. A process called directed initialization is proposed to improve EECA's learning efficiency. Because EECA learns the data point distribution in every cluster by adjusting an ellipsoid with suitable size and orientation, the information contained in the ellipsoid is further utilized to improve the cluster validity. A cluster validity measure based on the ratio of summation for each intra-cluster scatter with respect to the inter-cluster separation is defined in this paper. The proposed cluster validity measure takes advantage of EECA's learning capability and serves as an effective index for determining the adequate number of ellipsoids required for classification.

scholarly journals Geometry features and performance characteristics of an inland marine propeller

2015 ◽  
Vol 18 (4) ◽  
pp. 110-116
Author(s):  
Hieu Khanh Ngo ◽  
Hien Tat Le
Keyword(s):  
Laser Scanning ◽  
Reference Value ◽  
Performance Characteristics ◽  
Ho Chi Minh City ◽  
Marine Propeller ◽  
Operating Characteristics ◽  
Data Points ◽  
And Performance ◽  
Ship Propeller ◽  
Coordinate Data

Review performance characteristics of a marine propeller should be based on its geometric properties and the design standard of marine propeller. Based on an inland ship propeller which is currently widely used in the Ho Chi Minh city, the article provides a method of building a 3D model of this propeller from its coordinate data points obtained by a laser scanning devices. Then surveying the geometric characteristics of the marine propeller through 3D scanning, and making comparisons with the marine propeller manufacturing standards in the world in order to estimate the operating characteristics of this marine propeller. The analysis results obtained in the article can be used as a reference value for the simulation results of the characteristics of this insland marine propeller, as well as the experimental results on a miniature model of this propeller.

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