scholarly journals Iterative closest point registration for fast point feature histogram features of a volume density optimization algorithm

2020 ◽  
Vol 53 (1-2) ◽  
pp. 29-39 ◽  
Author(s):  
Lu-shen Wu ◽  
Guo-lin Wang ◽  
Yun Hu
Keyword(s):  
Coordinate System ◽  
Optimization Algorithm ◽  
Point Cloud ◽  
High Speed ◽  
Local Coordinate System ◽  
Volume Density ◽  
Iterative Closest Point ◽  
Registration Accuracy ◽  
Fine Registration ◽  
Point Feature

Motivated by the high speed but insufficient precision of the existing fast point feature histogram algorithm, a new fast point feature histogram registration algorithm based on density optimization is proposed. In this method, a 44-section blank feature histogram is first established, and then a principal component analysis is implemented to calculate the normal of each point in the point cloud. By translating the coordinate system in the established local coordinate system, the normal angle of each point pair and its weighted neighborhood are obtained, and then a fast point feature histogram with 33 sections is established. The reciprocal of the volume density for the central point and its weighted neighborhood are calculated simultaneously. The whole reciprocal space is divided into 11 sections. Thus, a density fast point feature histogram with 44 sections is obtained. On inputting the testing models, the initial pose of the point cloud is adjusted using the traditional fast point feature histogram and the proposed algorithms, respectively. Then, the iterative closest point algorithm is incorporated to complete the fine registration test. Compared with the traditional fine registration test algorithm, the proposed optimization algorithm can obtain 44 feature parameters under the condition of a constant time complexity. Moreover, the proposed optimization algorithm can reduce the standard deviation by 8.6% after registration. This demonstrates that the proposed method encapsulates abundant information and can achieve a high registration accuracy.

A Finite Element Formulation of Flexible Slider Crank Mechanism Using Local Coordinates

1994 ◽  
Author(s):  
Behrooz Fallahi ◽  
S. Lai ◽  
C. Venkat
Keyword(s):  
Rigid Body ◽  
Coordinate System ◽  
High Speed ◽  
Displacement Vector ◽  
Lagrange Equation ◽  
Local Coordinate System ◽  
Body Motion ◽  
Elastic Displacement ◽  
Global Coordinate System ◽  
Element Formulation

Abstract The need for higher productivity has lead to the design of machines operating at higher speeds. At high speed the rigid body assumption is no longer valid and the links should be considered flexible. In this work a method which is based on Modified Lagrange Equation for modeling flexible mechanism is presented. The method posses a more computational efficiency for not requiring the transformation from the local coordinate system to the global coordinate system. Also an approach using the homogeneous coordinate for element matrices generation is presented. The approach leads to a formalism where the displacement vector is expressed as a product of two matrices and a vector. The first matrix is a function of rigid body motion. The second matrix is a function of rigid body configuration. The vector is a function of elastic displacement. This formal separation helps to facilitate the generation of element matrices using symbolic manipulations.

scholarly journals Three-Dimensional Linear Restoration of a Tunnel Based on Measured Track and Uncontrolled Mobile Laser Scanning

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3815
Author(s):  
Yulong Han ◽  
Haili Sun ◽  
Ruofei Zhong
Keyword(s):  
Coordinate System ◽  
Point Cloud ◽  
Laser Scanning ◽  
Large Scale ◽  
Local Coordinate System ◽  
Vertical Direction ◽  
Measurement Technology ◽  
Subway Tunnel ◽  
Average Deviation ◽  
Design Data

Traditional precision measurement adopts discrete artificial static observation, which cannot meet the demands of the dynamic, continuous, fine and high-precision holographic measurement of large-scale infrastructure construction and complex operation and maintenance management. Due to its advantages of fast, accurate and convenient measurement, mobile laser scanning technology is becoming a popular technology in the maintenance and measurement of infrastructure construction such as tunnels. However, in some environments without satellite signals, such as indoor areas and underground spaces, it is difficult to obtain 3D data by means of mobile measurement technology. This paper proposes a method to restore the linear of the point cloud obtained by mobile laser scanning based on the measured track center line. In this paper, the measured track position is interpolated with a cubic spline to calculate the translations, and the rotation parameters are calculated by combining the simulation design data. The point cloud of the cross-section of the tunnel under the local coordinate system is converted to the absolute coordinate system to calculate the tunnel line. In addition, the method is verified by experiments combined with the subway tunnel data, and the overall point error can be controlled to within 0.1 m. The average deviation in the horizontal direction is 0.0551 m, and that in the vertical direction is 0.0274 m. Compared with the previous methods, this method can effectively avoid the obvious deformation of the tunnel and the sharp increase in the error, and can process the tunnel point cloud data more accurately and quickly. It also provides better data support for subsequent tunnel analysis such as 3D display, completion survey, systematic hazard management and so on.

Image Registration for Multimodal Inspection of Mechanical Parts

2003 ◽  
Author(s):  
Yanyan Wu ◽  
Chunhe Gong
Keyword(s):  
Image Registration ◽  
Point Cloud ◽  
Computational Algorithm ◽  
Iterative Closest Point ◽  
Research Focus ◽  
Registration Accuracy ◽  
Multimodal Registration ◽  
Mechanical Parts ◽  
Iterative Closest Point Algorithm ◽  
Inspection Data

Image registration is the process of aligning the corresponding features of images in the same coordinate system. Multimodal registration has been widely used in medical imaging and geographic imaging. However, it has not been broadly applied in the inspection imaging of mechanical parts. Multimodal registration can improve inspection accuracy and quality by combining complementary inspection data from different inspection methods, or “modalities”. The research focus of this work is to develop a computational algorithm to register a CMM point cloud with a CT image in the 2-D (planar) domain. Dealing with outliers is the major concern for achieving required registration accuracy. Targeting solving this problem, a new registration metric is proposed in this work, which makes application of the traditional ICP (Iterative Closest Point) algorithm robust, by optimizing the search for closest points.

scholarly journals QUALIFICATION OF POINT CLOUDS MEASURED BY SFM SOFTWARE

2015 ◽  
Vol XL-4/W5 ◽  
pp. 125-130 ◽  
Author(s):  
K. Oda ◽  
S. Hattori ◽  
H. Saeki ◽  
T. Takayama ◽  
R. Honma
Keyword(s):  
Coordinate System ◽  
Structure From Motion ◽  
Point Cloud ◽  
Point Clouds ◽  
Sum Of Squares ◽  
Iterative Closest Point ◽  
Test Results ◽  
Reference Coordinate System ◽  
The Difference

This paper proposes a qualification method of a point cloud created by SfM (Structure-from-Motion) software. Recently, SfM software is popular for creating point clouds. Point clouds created by SfM Software seems to be correct, but in many cases, the result does not have correct scale, or does not have correct coordinates in reference coordinate system, and in these cases it is hard to evaluate the quality of the point clouds. To evaluate this correctness of the point clouds, we propose to use the difference between point clouds with different source of images. If the shape of the point clouds with different source of images is correct, two shapes of different source might be almost same. To compare the two or more shapes of point cloud, iterative-closest-point (ICP) is implemented. Transformation parameters (rotation and translation) are iteratively calculated so as to minimize sum of squares of distances. This paper describes the procedure of the evaluation and some test results.

CONSTRUCTION OF FRAME GEODETIC NETWORK FOR ENGINEERING SURVEY OF RAIL TRANSPORT FACILITIES

2018 ◽  
Vol 12 (5-6) ◽  
pp. 58-71
Author(s):  
A. Yu. Matveev ◽  
I. P. Gavrilova ◽  
A. V. Kovyazin ◽  
E. V. Brovkov
Keyword(s):  
Coordinate System ◽  
High Speed ◽  
Local Coordinate System ◽  
Geodetic Network ◽  
Local System ◽  
Rail Transport ◽  
Reference Network ◽  
Coordinate Systems ◽  
Railway Traffic ◽  
Engineering Survey

Increasing the speed of trains along railroad tracks and the development of satellite geodetic technologies put forward new requirements for the production of the engineering survey at the rail transport facilities. Ensuring the safety of high-speed traffic is directly related to the accuracy of determining the coordinates and heights of the reference geodetic networks created for the design, construction, reconstruction and operation of railways. A large length of Railways in Russia requires solving a number of problems in the conditions of increasing the accuracy of determining the coordinates. High-speed route crosses several regions with its own local coordinate systems. Simplify the design and cadastral works and reduce to minimum linear distortions when performing geodetic measurements, allows the creation of a local coordinate system, unified for the entire route. The technology of creating a unified local coordinate system for linear objects passing through several 6-degree zones in the projection of GaussKruger and objects located at an angle to the axial Meridian is considered on the example of the railway Moscow — Saint-Petersburg — Vyborg. At the basis of a unified local system of the object, it is proposed to use an oblique cylindrical cartographic projection. Implemented a coordinate system in the form of the software, allowing to perform transformations between the local system, the world and state coordinate systems. The paper also considers the practical experience of creating a high-precision geodetic reference network for a high-speed railway traffic route, which can be used for various linear engineering structures. The created frame network can serve as a geodetic base for performing laser scanning, monitoring facilities, creating geoinformation systems and solving other problems that arise during the operation of an engineering facility.

scholarly journals ACCURACY ASSESSMENT OF POINT CLOUDS GEO-REFERENCING IN SURVEYING AND DOCUMENTATION OF HISTORICAL COMPLEXES

2017 ◽  
Vol XLII-5/W1 ◽  
pp. 161-165 ◽  
Author(s):  
A. Fryskowska
Keyword(s):  
Coordinate System ◽  
Laser Scanning ◽  
Accuracy Assessment ◽  
Local Coordinate System ◽  
Three Dimensional ◽  
Point Clouds ◽  
Digital Culture ◽  
Global Coordinate System ◽  
Registration Accuracy ◽  
Factors Affecting

Terrestrial Laser Scanning (TLS) technique is widely used for documentation and preservation of historical sites by for example creating three-dimensional (3-D) digital models or vectorial sketches. In consequence, a complex, complete, detail and accurate documentation of historical structure is created. It is very crucial when it comes about modern digital culture. <br><br> If we acquire TLS data of once particular structure usually we do it in local coordinate system of scanner. Nevertheless when measurements are conducted for complex of several historical buildings or monuments (i.e. castle ruins, building of narrow streets of the Old Towns), the registration of point clouds into a common, global coordinate system is one of the critical steps in TLS data processing. Then we have integrate data with different accuracy level. Inner accuracy of local coordinate system (scanner system) is usually thrice higher than for global coordinate systems measurement. <br><br> The paper describes the geometric quality of the direct georeferencing in post-processing, considering surveying points. Then, an analysis of factors affecting registration accuracy is proposed. Finally, an improvement of direct georeferencing technique is presented and examined. Furthermore, registered data and chosen orientation methods have been compared to each other.

Registration and Fusion of UAV LiDAR System Sequence Images and Laser Point Clouds

2020 ◽  
Author(s):  
Jiayong Yu ◽  
Longchen Ma ◽  
Maoyi Tian, ◽  
Xiushan Lu
Keyword(s):  
Point Cloud ◽  
Image Data ◽  
Point Clouds ◽  
Optical Image ◽  
Point Cloud Data ◽  
Feature Points ◽  
Lidar System ◽  
Registration Accuracy ◽  
Cloud Data ◽  
Intensity Image

The unmanned aerial vehicle (UAV)-mounted mobile LiDAR system (ULS) is widely used for geomatics owing to its efficient data acquisition and convenient operation. However, due to limited carrying capacity of a UAV, sensors integrated in the ULS should be small and lightweight, which results in decrease in the density of the collected scanning points. This affects registration between image data and point cloud data. To address this issue, the authors propose a method for registering and fusing ULS sequence images and laser point clouds, wherein they convert the problem of registering point cloud data and image data into a problem of matching feature points between the two images. First, a point cloud is selected to produce an intensity image. Subsequently, the corresponding feature points of the intensity image and the optical image are matched, and exterior orientation parameters are solved using a collinear equation based on image position and orientation. Finally, the sequence images are fused with the laser point cloud, based on the Global Navigation Satellite System (GNSS) time index of the optical image, to generate a true color point cloud. The experimental results show the higher registration accuracy and fusion speed of the proposed method, thereby demonstrating its accuracy and effectiveness.

Establishment of local coordinate systems in the transition to the geodetic system of coordinates of GSK-2011

2017 ◽  
Vol 929 (11) ◽  
pp. 2-10
Author(s):  
A.V. Vinogradov
Keyword(s):  
Coordinate System ◽  
Small Businesses ◽  
Transition Period ◽  
Local Coordinate System ◽  
Initial Point ◽  
Central Meridian ◽  
Administrative District ◽  
Local Networks ◽  
Small Areas ◽  
Geodetic System

Pretty before long there will be transition to the geodetic system of coordinates of GSK-2011. For the transition period it is necessary to develop a method of recalculating coordinates from one system to another. The existing methods of recalculating coordinates are designed for recalculating coordinate points of state geodetic networks (GGS) and geodetic local networks (GSS). For small areas (administrative districts, populated areas) simplified methods are more acceptable. You need to choose the resampling methods that can be applied in small businesses, performing surveying works. The article presents the the results of calculations of changes of coordinates of the same point in GSK-2011 and SC-95 in six-degree zones of Gauss projection. It was found that in each region values of the shifts changed to small ones. Therefore, it is possible to convert the coordinates of the points by the simplified formulae. For recalculation from the coordinates of GSK-2011 in SK-95 or local coordinate system (WCS) of the administrative district it is necessary to find the origin of coordinates, scale value and rotation of the coordinate axes. The error of the conversion shall not exceed 0,001 m. The coordinates of the initial point of the local coordinate system relative to the central meridian of the local coordinate system shall be added in the list of parameters of the transition from local coordinate system to the state one.

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