Measurements based specular reflection formulation for point cloud modelling

Purpose – The purpose of this paper is to investigate the influence of surface topology on the performance of laser line scanning probe and to suggest methodology for 3D digitization of specular surfaces. Design/methodology/approach – Two different molds, one having milled surface and the other with polished surface, were used to identify effect of surface characteristics on the performance of laser line scanning probe mounted on bridge-type coordinate measuring machine. The point cloud data acquisition of two surfaces was carried out using different combinations of laser scanning parameters. The point cloud sets thus obtained were analyzed in terms of completeness, noise and accuracy. The polished mold which exhibited specular reflection was digitized at different scanning angles of laser line scanning probe using the best combination of scanning parameters. Findings – Results confirmed that surface characteristics play important role to determine quality of the reverse engineering (RE) process. The results in terms of completeness, accuracy and noise for point cloud sets have successfully been obtained for milled and polished surfaces. Three-dimensional (3D) comparison analysis suggested larger deviation in cases of polished surface as compared to milled surface. The point cloud set acquired with proposed approach was better in terms of both completeness and noise reduction. Originality/value – There has been an increased demand for measurement of metallic, polished and shiny surfaces in automotive, aerospace and medical industries. These surfaces are very difficult to scan because they exhibit specular reflection instead of diffuse reflection. Laser line scanning probe which is a non-contact method is in great demand for RE. This is due to the fact that it possesses very high data acquisition speed. However, laser scanning is hugely affected by surface characteristics which in turn govern specular reflection.In this paper, it has been shown that a surface that exhibits various degrees of specular reflection can be digitized efficiently if appropriate combination of scanning parameters and positions of laser line scanning probe are used. Also, this paper has attempted to offer a procedure to overcome incompleteness and noise in 3D data as obtained by the laser line scanning probe.

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Framework for 3D Point Cloud Modelling Aimed at Road Sight Distance Estimations

Remote Sensing ◽

10.3390/rs11232730 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2730

Author(s):

González-Gómez ◽

Iglesias ◽

Rodríguez-Solano ◽

Castro

Keyword(s):

Point Cloud ◽

Three Dimensional ◽

The Road ◽

3D Objects ◽

Sight Distance ◽

Road Geometry ◽

Three Dimensional Models ◽

The Individual ◽

Periodic Evaluation ◽

Cloud Modelling

Existing roads require periodic evaluation in order to ensure safe transportation. Estimations of the available sight distance (ASD) are fundamental to make sure motorists have sufficient visibility to perform basic driving tasks. Mobile LiDAR Systems (MLS) can provide these evaluations with accurate three-dimensional models of the road and surroundings. Similarly, Geographic Information System (GIS) tools have been employed to obtain ASD. Due to the fact that widespread GIS formats used to store digital surface models handle elevation as an attribute of location, the presented methodology has separated the representation of ground and aboveground elements. The road geometry and surrounding ground are stored in digital terrain models (DTM). Correspondingly, abutting vegetation, manmade structures, road assets and other roadside elements are stored in 3D objects and placed on top of the DTM. Both the DTM and 3D objects are accurately obtained from a denoised and classified LiDAR point cloud. Based on the consideration that roadside utilities and most manmade structures are well-defined geometric elements, some visual obstructions are extracted and/or replaced with 3D objects from online warehouses. Different evaluations carried out with this method highlight the tradeoff between the accuracy of the estimations, performance and geometric complexity as well as the benefits of the individual consideration of road assets.

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POINT CLOUD MODELLING BASED ON THE TUNNEL AXIS AND BLOCK ESTIMATION FOR MONITORING THE BADALING TUNNEL, CHINA

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w7-301-2017 ◽

2017 ◽

Vol XLII-2/W7 ◽

pp. 301-306 ◽

Cited By ~ 1

Author(s):

J. Wang ◽

H. B. Zheng ◽

H. Huang ◽

G. W. Ma

Keyword(s):

Point Cloud ◽

Laser Scanning ◽

Point Clouds ◽

Winter Olympics ◽

Representative Points ◽

Value Decomposition ◽

Cloud Modelling ◽

Svd Method ◽

Beijing China

Recent years have witnessed a growing investigation of terrestrial laser scanning (TLS) for monitoring the deformation of tunnels. TLS provides the ability to obtain a more accurate and complete description of the tunnel surfaces, allowing the determination of the mechanism and magnitude of tunnel deformation, because the entire surface of the tunnel is more concretely modelled rather than being represented by a number of points. This paper models and analyses the point clouds from TLS to detect the possible deformation of a newly built tunnel. In the application of monitoring the Badaling Tunnel for the Winter Olympics 2020 in Beijing, China, the proposed method includes the following components: the tunnel axis is automatically estimated based on a 3D quadratic form estimation; all of the point clouds are segmented into axis-based blocks; and representative points, solved by a singular value decomposition (SVD) method, are estimated to describe the tunnel surface and establish the correspondence of data between days. The deformations are detected in the form of the distance discrepancies of representative points and verified by the measurements using total station.

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Forensic applications of IR infrared microscopic internal reflection spectroscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100132273 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1528-1529

Author(s):

Edward G. Bartick ◽

John A. Reffner

Keyword(s):

Specular Reflection ◽

Forensic Analysis ◽

Attenuated Total Reflection ◽

Internal Reflection ◽

Standard Size ◽

Ir Microscopy ◽

Ir Analysis ◽

Plastic Explosives ◽

Internal Reflection Spectroscopy ◽

Reflectance Measurements

Since the introduction of commercial Fourier transform infrared (FTIR) microscopic systems in 1983, IR microscopy has developed as an important analytical tool in research, industry and forensic analysis. Because of the frequent encounter of small quantities of physical evidence found at crime scenes, spectroscopic IR microscopes have proven particularly valuable for forensic applications. Transmittance and reflectance measurements have proven very useful. Reflection-absorption, specular reflection, and diffuse reflection have all been applied. However, it has been only very recently that an internal reflection (IRS) objective has been commercially introduced.The IRS method, also known as attenuated total reflection (ATR), has proven very useful for IR analysis of standard size samples. The method has been applied to adhesive tapes, plastic explosives, and general applications in the analysis of opaque materials found as evidence. The small quantities or uncontaminated areas of specimens frequently found requiring forensic analysis will often be directly applicable to microscopic IRS analysis.

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Valence electron energy loss spectroscopy in reflection geometry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100153865 ◽

1989 ◽

Vol 47 ◽

pp. 378-379

Author(s):

J. Liu ◽

J. M. Cowley

Keyword(s):

Energy Loss ◽

Valence Electron ◽

Interband Transition ◽

Specular Reflection ◽

Three Dimensional ◽

Electron Excitation ◽

Transmission Electron ◽

Yield Information ◽

Valence Bands ◽

Excitation Processes

The low energy loss region of a EELS spectrum carries information about the valence electron excitation processes (e.g., collective excitations for free electron like materials and interband transitions for insulators). The relative intensities and the positions of the interband transition energy loss peaks observed in EELS spectra are determined by the joint density of states (DOS) of the initial and final states of the excitation processes. Thus it is expected that EELS in reflection mode could yield information about the perturbation of the DOS of the conduction and valence bands of the bulk crystals caused by the termination of the three dimensional periodicity at the crystal surfaces. The experiments were performed in a Philipps 400T transmission electron microscope operated at 120 kV. The reflection EELS spectra were obtained by a Gatan 607 EELS spectrometer together with a Tracor data acquisition system and the resolution of the spectrometer was about 0.8 eV. All the reflection spectra are obtained from the specular reflection spots satisfying surface resonance conditions.

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Analysis of Efficient Visualization and Interactive Editing of 3D Point Cloud Data

TECHART Journal of Arts and Imaging Science ◽

10.15323/techart.2016.05.3.2.32 ◽

2016 ◽

Vol 3 (2) ◽

pp. 32

Author(s):

Rekha Patil ◽

Ashok Kumar Patil ◽

Youngho Chai

Keyword(s):

Point Cloud ◽

3D Point Cloud ◽

Point Cloud Data ◽

Cloud Data ◽

Interactive Editing

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A Proposal of 3D Feature based on Occupancy of Point Cloud in Multi-Scale Shell Region

IEEJ Transactions on Electronics Information and Systems ◽

10.1541/ieejeiss.136.1078 ◽

2016 ◽

Vol 136 (8) ◽

pp. 1078-1084

Author(s):

Shoichi Takei ◽

Shuichi Akizuki ◽

Manabu Hashimoto

Keyword(s):

Point Cloud ◽

Multi Scale ◽

Feature Based ◽

Shell Region

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

Journal of Imaging Science and Technology ◽

10.2352/j.imagingsci.technol.2021.65.1.01050110.2352/j.imagingsci.technol.2021.65.1.010501 ◽

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.

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