scholarly journals Research on laser stripe characteristics and center extraction algorithm for desktop laser scanner

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Xiaoquan Shi ◽  
Yazhou Sun ◽  
Haitao Liu ◽  
Linqi Bai ◽  
Chonghao Lin
Keyword(s):  
Laser Scanner ◽  
Bright Spot ◽  
Distribution Characteristics ◽  
Ambient Light ◽  
Centroid Method ◽  
Laser Stripe ◽  
Wide Range ◽  
Laser Scanners ◽  
Extraction Algorithm ◽  
Large Width

AbstractThis study presents laser stripe center extraction algorithm for desktop-level 3D laser scanners. The laser stripe center extraction accuracy is an important factor affecting 3D scanning result. Desktop-level devices should have adaptability of a wide range of scanning objects. In this paper, laser stripe energy distribution characteristics with different laser stripe width, ambient light, materials and colors are obtained by experiments. Experiment results show that waveforms of bright spot, low brightness stripe and stripe with large width are complex or easily disturbed, so the center extraction algorithm of them are studied. The extraction effects of extremum method, gradient method and gray centroid method under different conditions are compared. Based on traditional grayscale value, a weighted grayscale value is proposed to extract laser stripe center. Standard deviations of extracted pixel position and fitting pixel position are calculated by different method with different weighted grayscale value. For different conditions, especially for different ambient light intensity, weight matrix plays an important role to extraction result.

scholarly journals MULTI-WAVELENGTHS 3D LASER SCANNING FOR PIGMENT AND STRUCTURAL STUDIES ON THE FRESCOED CEILING <q>THE TRIUMPH OF DIVINE PROVIDENCE</q>

2019 ◽  
Vol XLII-2/W15 ◽  
pp. 549-554 ◽  
Author(s):  
M. Guarneri ◽  
S. Ceccarelli ◽  
M. Ferri De Collibus ◽  
M. Francucci ◽  
M. Ciaffi
Keyword(s):  
Cultural Heritage ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Distance Estimation ◽  
Laser Source ◽  
Divine Providence ◽  
Ambient Light ◽  
Pietro Da Cortona ◽  
Laser Scanners ◽  
Laser Sources

<p><strong>Abstract.</strong> The modern 3D digitalization techniques open new scenarios on how to transmit to the next generations the state of health of Cultural Heritage (CH) buildings, paintings, frescos or statues. The final goal of the 3D digitalization is an exact replica of the acquired target, but a standard and unique technique able to digitalize artworks of different size and in different ambient light conditions is still far from being successfully ready for the CH field. Even if both laser scanning and photogrammetry can be considered mature techniques, applied with success in most of the Cultural Heritage study cases, they are limited in terms of colour digitalization and image quality in all the cases where ambient light and big sensor-target distances are crucial factors: differently to standard laser scanners, which collect colour information by the use of a coaxial camera and the distance by an IR laser source, the RGB-ITR (Red, Green and Blue Imaging Topological Radar) scanner, developed in ENEA, is equipped with three different laser sources for the simultaneous colour and distance estimation. The present work shows the results obtained applying the above-mentioned multi-wavelengths laser scanner for collecting a complete high-quality 3D colour model of “The Triumph of Divine Providence” vault, painted by Pietro da Cortona on the ceiling of the noble hall inside Palazzo Barberini in Rome.</p>

Handheld Laser Scanner Research

2019 ◽  
Vol 952 (10) ◽  
pp. 47-54
Author(s):  
A.V. Komissarov ◽  
A.V. Remizov ◽  
M.M. Shlyakhova ◽  
K.K. Yambaev
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Test Site ◽  
Optical Systems ◽  
Advantages And Disadvantages ◽  
Site Survey ◽  
Laser Scanners ◽  
Three Dimensional Models ◽  
The Stability

The authors consider hand-held laser scanners, as a new photogrammetric tool for obtaining three-dimensional models of objects. The principle of their work and the newest optical systems based on various sensors measuring the depth of space are described in detail. The method of simultaneous navigation and mapping (SLAM) used for combining single scans into point cloud is outlined. The formulated tasks and methods for performing studies of the DotProduct (USA) hand-held laser scanner DPI?8X based on a test site survey are presented. The accuracy requirements for determining the coordinates of polygon points are given. The essence of the performed experimental research of the DPI?8X scanner is described, including scanning of a test object at various scanner distances, shooting a test polygon from various scanner positions and building point cloud, repeatedly shooting the same area of the polygon to check the stability of the scanner. The data on the assessment of accuracy and analysis of research results are given. Fields of applying hand-held laser scanners, their advantages and disadvantages are identified.

scholarly journals LiDAR-Based Glass Detection for Improved Occupancy Grid Mapping

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2263
Author(s):  
Haileleol Tibebu ◽  
Jamie Roche ◽  
Varuna De Silva ◽  
Ahmet Kondoz
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
Light Detection And Ranging ◽  
Test Results ◽  
New Approach ◽  
Occupancy Grid ◽  
Laser Scanners ◽  
Novel Method ◽  
Occupancy Grid Mapping ◽  
Cartesian Coordinate

Creating an accurate awareness of the environment using laser scanners is a major challenge in robotics and auto industries. LiDAR (light detection and ranging) is a powerful laser scanner that provides a detailed map of the environment. However, efficient and accurate mapping of the environment is yet to be obtained, as most modern environments contain glass, which is invisible to LiDAR. In this paper, a method to effectively detect and localise glass using LiDAR sensors is proposed. This new approach is based on the variation of range measurements between neighbouring point clouds, using a two-step filter. The first filter examines the change in the standard deviation of neighbouring clouds. The second filter uses a change in distance and intensity between neighbouring pules to refine the results from the first filter and estimate the glass profile width before updating the cartesian coordinate and range measurement by the instrument. Test results demonstrate the detection and localisation of glass and the elimination of errors caused by glass in occupancy grid maps. This novel method detects frameless glass from a long range and does not depend on intensity peak with an accuracy of 96.2%.

scholarly journals Metric Accuracy Evaluation of Dense Matching Algorithms in Archeological Applications

2011 ◽  
Vol 6 ◽  
pp. 275-282 ◽  
Author(s):  
C. Re ◽  
S. Robson ◽  
R. Roncella ◽  
M Hess
Keyword(s):  
Laser Scanner ◽  
Medium Size ◽  
Accuracy Evaluation ◽  
Software Packages ◽  
Dense Matching ◽  
Laser Scanners ◽  
Surface Models ◽  
University College London ◽  
Archaeological Artifacts ◽  
Archaeological Objects

In the cultural heritage field the recording and documentation of small and medium size objects with very detailed Digital Surface Models (DSM) is readily possible by through the use of high resolution and high precision triangulation laser scanners. 3D surface recording of archaeological objects can be easily achieved in museums; however, this type of record can be quite expensive. In many cases photogrammetry can provide a viable alternative for the generation of DSMs. The photogrammetric procedure has some benefits with respect to laser survey. The research described in this paper sets out to verify the reconstruction accuracy of DSMs of some archaeological artifacts obtained by photogrammetric survey. The experimentation has been carried out on some objects preserved in the Petrie Museum of Egyptian Archaeology at University College London (UCL). DSMs produced by two photogrammetric software packages are compared with the digital 3D model obtained by a state of the art triangulation color laser scanner. Intercomparison between the generated DSM has allowed an evaluation of metric accuracy of the photogrammetric approach applied to archaeological documentation and of precision performances of the two software packages.

scholarly journals FINE REGISTRATION OF KILO-STATION NETWORKS - A MODERN PROCEDURE FOR TERRESTRIAL LASER SCANNING DATA SETS

2016 ◽  
Vol XLI-B5 ◽  
pp. 485-492
Author(s):  
J.-F. Hullo
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Data Sets ◽  
Data Set ◽  
Information Models ◽  
3D Network ◽  
Laser Scanners ◽  
Building Information ◽  
Set Up ◽  
Fine Registration

We propose a complete methodology for the fine registration and referencing of kilo-station networks of terrestrial laser scanner data currently used for many valuable purposes such as 3D as-built reconstruction of Building Information Models (BIM) or industrial asbuilt mock-ups. This comprehensive target-based process aims to achieve the global tolerance below a few centimetres across a 3D network including more than 1,000 laser stations spread over 10 floors. This procedure is particularly valuable for 3D networks of indoor congested environments. In situ, the use of terrestrial laser scanners, the layout of the targets and the set-up of a topographic control network should comply with the expert methods specific to surveyors. Using parametric and reduced Gauss-Helmert models, the network is expressed as a set of functional constraints with a related stochastic model. During the post-processing phase inspired by geodesy methods, a robust cost function is minimised. At the scale of such a data set, the complexity of the 3D network is beyond comprehension. The surveyor, even an expert, must be supported, in his analysis, by digital and visual indicators. In addition to the standard indicators used for the adjustment methods, including Baarda’s reliability, we introduce spectral analysis tools of graph theory for identifying different types of errors or a lack of robustness of the system as well as <i>in fine</i> documenting the quality of the registration.

scholarly journals TERRESTRIAL LASER SCANNERS SELF-CALIBRATION STUDY: DATUM CONSTRAINTS ANALYSES FOR NETWORK CONFIGURATIONS

2015 ◽  
Vol XL-2/W4 ◽  
pp. 1-9 ◽  
Author(s):  
M. A. Abbas ◽  
H. Setan ◽  
Z. Majid ◽  
A. K. Chong ◽  
L. Chong Luh ◽  
...  
Keyword(s):  
Laser Scanner ◽  
Network Configuration ◽  
Calibration Technique ◽  
Self Calibration ◽  
Laser Scanners ◽  
Different Types ◽  
Minimum Number ◽  
Calibration Study ◽  
Different Sources ◽  
Selection Of

Similar to other electronic instruments, terrestrial laser scanner (TLS) can also inherent with various systematic errors coming from different sources. Self-calibration technique is a method available to investigate these errors for TLS which were adopted from photogrammetry technique. According to the photogrammetry principle, the selection of datum constraints can cause different types of parameter correlations. However, the network configuration applied by TLS and photogrammetry calibrations are quite different, thus, this study has investigated the significant of photogrammetry datum constraints principle in TLS self-calibration. To ensure that the assessment is thorough, the datum constraints analyses were carried out using three variant network configurations: 1) minimum number of scan stations; 2) minimum number of surfaces for targets distribution; and 3) minimum number of point targets. Based on graphical and statistical, the analyses of datum constraints selection indicated that the parameter correlations obtained are significantly similar. In addition, the analysis has demonstrated that network configuration is a very crucial factor to reduce the correlation between the calculated parameters.

scholarly journals ON PRACTICAL ACCURACY ASPECTS OF UNMANNED AERIAL VEHICLES EQUIPPED WITH SURVEY GRADE LASER SCANNERS

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 343-348
Author(s):  
K. Nakano ◽  
Y. Tanaka ◽  
H. Suzuki ◽  
K. Hayakawa ◽  
M. Kurodai
Keyword(s):  
Unmanned Aerial Vehicles ◽  
High Performance ◽  
Laser Scanner ◽  
Image Sensors ◽  
Measuring Devices ◽  
Aerial Vehicles ◽  
Laser Scanners ◽  
Surface Models ◽  
Reconstruction Software ◽  
Practical Accuracy

Abstract. Unmanned aerial vehicles (UAVs) equipped with image sensors, which have been widely used in various fields such as construction, agriculture, and disaster management, can obtain images at the millimeter to decimeter scale. Useful tools that produce realistic surface models using 3D reconstruction software based on computer vision technologies are generally used to produce datasets from acquired images using UAVs. However, it is difficult to obtain the feature points from surfaces with limited texture, such as new asphalt or concrete, or detect the ground in areas such as forests, which are commonly concealed by vegetation. A promising method to address such issues is the use of UAV-equipped laser scanners. Recently, low and high performance products that use direct georeferencing devices integrated with laser scanners have been available. Moreover, there have been numerous reports regarding the various applications of UAVs equipped with laser scanners; however, these reports only discuss UAVs as measuring devices. Therefore, to understand the functioning of UAVs equipped with laser scanners, we investigated the theoretical accuracy of the survey grade laser scanner unit from the viewpoint of photogrammetry. We evaluated the performance of the VUX-1HA laser scanner equipped on a Skymatix X-LS1 UAV at a construction site. We presented the theoretical values obtained using the observation equations and results of the accuracy aspects of the acquired data in terms of height.

scholarly journals Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study

2013 ◽  
Vol 14 (2) ◽  
pp. 265-268 ◽  
Author(s):  
Naveen S Yadav ◽  
Teerthesh Jain ◽  
Amrita Pandita ◽  
SMA Feroz ◽  
Pradeep LNU ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Laser Scanner ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Time Intervals ◽  
Impression Material ◽  
Impression Materials ◽  
Laser Scanners ◽  
Master Model

ABSTRACT Aim Aim of the present study was to comparatively evaluate dimensional accuracy of newely introduced elastomeric impression material after repeated pours at different time intervals. Materials and methods In the present study a total of 20 (10 + 10) impressions of master model were made from vinyl polyether silicone and vinyl polysiloxane impression material. Each impression was repeatedly poured at 1, 24 hours and 14 days. Therefore, a total of 60 casts were obtained. Casts obtained were scanned with three-dimensional (3D) laser scanner and measurements were done. Results Vinyl polyether silicone produced overall undersized dies, with greatest change being 0.14% only after 14 days. Vinyl polysiloxane produced smaller dies after 1 and 24 hours and larger dies after 14 days, differing from master model by only 0.07% for the smallest die and to 0.02% for the largest die. Conclusion All the deviations measured from the master model with both the impression materials were within a clinically acceptable range. Clinical significance In a typical fixed prosthodontic treatment accuracy of prosthesis is critical as it determines the success, failure and the prognosis of treatment including abutments. This is mainly dependent upon fit of prosthesis which in turn is dependent on dimensional accuracy of dies, poured from elastomeric impressions. How to cite this article Pandita A, Jain T, Yadav NS, Feroz SMA, Pradeep, Diwedi A. Evaluation and Comparison of Dimensional Accuracy of Newly Introduced Elastomeric Impression Material using 3D Laser Scanners: An in vitro Study. J Contemp Dent Pract 2013;14(2):265-268.

scholarly journals A Normalization scheme for Terrestrial LiDAR Intensity Data by Range and Incidence Angle

2018 ◽  
Author(s):  
Sandeep Sasidharan
Keyword(s):  
Incidence Angle ◽  
Autonomous Vehicle ◽  
Laser Scanner ◽  
Spectral Information ◽  
Intensity Data ◽  
Automatic Registration ◽  
Terrestrial Lidar ◽  
Intensity Information ◽  
Laser Scanners ◽  
Normalization Scheme

Automatic registration, classification and segmentation of Terrestrial Laser Scanner (TLS) data are of great interest in Geoinformatics &amp; Autonomous vehicle research. Along with dense and accurate 3D geometric data, laser scanners also collect return intensity information. Inclusion of this spectral information has potential to improve the working of the above mentioned processes. However, these intensity values need to be normalized, prior to their use, as they are subject to a large number of errors. This paper presents a technique to carry out normalization of intensity values using the range and incidence angle corrections. The developed approach has been tested on a large number of data and results are found satisfactory.

scholarly journals Spectral and spatial information from a novel dual-wavelength full-waveform terrestrial laser scanner for forest ecology

2018 ◽  
Vol 8 (2) ◽  
pp. 20170049 ◽  
Author(s):  
F. Mark Danson ◽  
Fadal Sasse ◽  
Lucy A. Schofield
Keyword(s):  
Field Experiments ◽  
Forest Ecology ◽  
Laser Scanner ◽  
Dual Wavelength ◽  
Leaf Biomass ◽  
Terrestrial Laser Scanner ◽  
Area Index ◽  
Waveform Data ◽  
Full Waveform ◽  
Wide Range

The Salford Advanced Laser Canopy Analyser (SALCA) is an experimental terrestrial laser scanner designed and built specifically to measure the structural and biophysical properties of forest canopies. SALCA is a pulsed dual-wavelength instrument with co-aligned laser beams recording backscattered energy at 1063 and 1545 nm; it records full-waveform data by sampling the backscattered energy at 1 GHz giving a range resolution of 150 mm. The finest angular sampling resolution is 1 mrad and around 9 million waveforms are recorded over a hemisphere above the tripod-mounted scanner in around 110 min. Starting in 2010, data pre-processing and calibration approaches, data analysis and information extraction methods were developed and a wide range of field experiments conducted. The overall objective is to exploit the spatial, spectral and temporal characteristics of the data to produce ecologically useful information on forest and woodland canopies including leaf area index, plant area volume density and leaf biomass, and to explore the potential for tree species identification and classification. This paper outlines the key challenges in instrument development, highlights the potential applications for providing new data for forest ecology, and describes new avenues for exploring information-rich data from the next generation of terrestrial laser scanners instruments like SALCA.

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