scholarly journals Assessing the Applicability of Mobile Laser Scanning for Mapping Forest Roads in the Republic of Korea

2020 ◽  
Vol 12 (9) ◽  
pp. 1502
Author(s):  
Hyeongkeun Kweon ◽  
Jung Il Seo ◽  
Joon-Woo Lee
Keyword(s):  
High Precision ◽  
Laser Scanning ◽  
Sustainable Forest Management ◽  
Low Cost ◽  
Unit Length ◽  
Environmental Damage ◽  
Positional Accuracy ◽  
Forest Roads ◽  
Forest Road ◽  
Cloud Data

Forest roads are an essential facility for sustainable forest management and protection. With advances in survey technology, such as Light Detection and Ranging, forest road maps with greater accuracy and resolution can be produced. This study produced a 3D map for establishment of a forest road inventory using a Mobile Laser Scanning (MLS) device mounted on a vehicle in four study forest roads in Korea, in order to review its precision, accuracy and efficiency based on comparisons with mapping using Total Station (TS) and Global Navigation Satellite System (GNSS). We counted the points that consist of the cloud data of the maps to determine the degree of precision density, and then compared this with 50 points at 20-m intervals on the centerlines bisecting the widths of the study forest roads. Then, we evaluated the relative positional accuracy of the MLS data based on three criteria: the total length of each forest road; the Root Mean Square Error (RMSE) obtained from coordinate values of the MLS and TS surveys compared to the GNSS survey; and the ratios of the centerlines extracted by the MLS and TS surveys overlaid to the buffer zone by the GNSS survey. Finally, we estimated the time and cost per unit length for producing the map to examine the efficiency of MLS mapping compared to the other two surveys. The results showed that the point cloud data acquired by the MLS survey on the study forest roads had very high precision and so is sufficient to produce a 3D forest road map with high-precision density and a low RMSE value. Although the equipment rental cost is somewhat high, the fact that information targeting on all spatial elements of forest roads can be obtained with a low cost of labor is a benefit when evaluating the efficiency of MLS survey and mapping. Our findings are expected to provide a quantitative assessment of both maintaining sustainable effectiveness and preventing potential environmental damage of forest roads.

scholarly journals A Model Study of Building Seismic Damage Information Extraction and Analysis on Ground-Based LiDAR Data

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Fan Yang ◽  
Xintao Wen ◽  
Xiaoshan Wang ◽  
Xiaoli Li ◽  
Zhiqiang Li
Keyword(s):  
High Precision ◽  
Laser Scanning ◽  
Full Range ◽  
Scientific Basis ◽  
Building Damage ◽  
Vector Model ◽  
Lidar Data ◽  
Emergency Relief ◽  
Cloud Data ◽  
Ground Based Lidar

Earthquake disasters can have a serious impact on people’s lives and property, with damage to buildings being one of the main causes of death and injury. A rapid assessment of the extent of building damage is essential for emergency response management, rescue operations, and reconstruction. Terrestrial laser scanning technology can obtain high precision light detection and ranging (LiDAR) point cloud data of the target. The technology is widely used in various fields; however, the quantitative analysis of building seismic information is the focus and difficulty of ground-based LiDAR data analysis processing. This paper takes full advantage of the high-precision characteristics of ground-based LiDAR data. A triangular network vector model (TIN-shaped model) was created in conjunction with the alpha shapes algorithm, solving the problem of small, nonvisually identifiable postearthquake building damage feature extraction bias. The model measures the length, width, and depth of building cracks, extracts the amount of wall tilt deformation, and labels the deformation zone. The creation of this model can provide scientific basis and technical support for postearthquake emergency relief, assessment of damage to buildings, extraction of deformation characteristics of other structures (bridges, tunnels, dams, etc.), and seismic reinforcement of buildings. The research data in this paper were collected by the author’s research team in the first time after the 2013 Lushan earthquake and is one of the few sets of foundation of LiDAR data covering the full range of postearthquake building types in the region, with the data information mainly including different damage levels of different structural types of buildings. The modeling analysis of this data provides a scientific basis for establishing the earthquake damage matrix of buildings in the region.

scholarly journals TRIANGULATION AND TIME-OF-FLIGHT BASED 3D DIGITISATION TECHNIQUES OF CULTURAL HERITAGE STRUCTURES

2021 ◽  
Vol XLIII-B2-2021 ◽  
pp. 825-830
Author(s):  
C. Altuntas
Keyword(s):  
Cultural Heritage ◽  
Laser Scanning ◽  
Low Cost ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Laser Scanner ◽  
Time Of Flight ◽  
Cost Effective ◽  
Cloud Data ◽  
Dense Point

Abstract. This study aims to introduce triangulation and ToF measurement techniques used in three-dimensional modelling of cultural heritages. These measurement techniques are traditional photogrammetry, SfM approach, laser scanning and time-of-flight camera. The computer based approach to photogrammetric measurement that is named SfM creates dense point cloud data in a short time. It is low-cost and very easy to application. However traditional photogrammetry needs a huge effort for creating 3D wire-frame model. On the other hand active measurement techniques such as terrestrial laser scanner and time-of-flight camera have also been used in three-dimensional modelling for more than twenty years. Each one has specific accuracy and measurement effectiveness. The large or small structures have different characters, and require proper measurement configurations. In this study, after these methods are introduced, their superior and weak properties in cultural heritage modelling to make high accuracy, high density and labour and cost effective measurement.

On the behaviour of low-volume unpaved resource access roads: effects of rehabilitation

1999 ◽  
Vol 26 (3) ◽  
pp. 262-269 ◽  
Author(s):  
C T Gnanendran ◽  
C Beaulieu
Keyword(s):  
Low Cost ◽  
Significant Proportion ◽  
Beam Deflection ◽  
Unit Weight ◽  
Forest Roads ◽  
Resource Access ◽  
Forest Road ◽  
The Road ◽  
Low Volume ◽  
And Performance

A new resurfacing method has been proposed recently for rehabilitating low-cost unpaved resource access (forest) roads using a mobile crusher. The quality and performance of the road rehabilitated using this new method have been a concern for some forestry companies and a study was initiated to compare it with the traditional resurfacing method where pit-run material is used. Two selected forest roads in New Brunswick, Canada, one resurfaced with the mobile crusher and the other resurfaced with pit-run material from a stationary crusher, were examined to assess the relative merits and deficiencies of the two methods. The particle-size distribution, maximum dry unit weight, and optimum water content for standard Proctor compaction were similar for the resurfacing materials derived from each method. The Benkelman beam deflection data suggest that the resulting roads from the two resurfacing methods were of similar structural capacity but the thickness of the gravel added and the level of compaction applied during resurfacing were different. Moreover, the materials from both methods contained a significant proportion of larger size particles exceeding 25.4 mm (1 in.) and failed to contain the required cohesive (binder) component.Key words: road rehabilitation, road resurfacing, mobile crusher, Benkelman beam, unpaved low volume road, forest road.

scholarly journals From Deposit to Point Cloud – a Study of Low-Cost Computer Vision Approaches for the Straightforward Documentation of Archaeological Excavations

2011 ◽  
Vol 6 ◽  
pp. 81-88 ◽  
Author(s):  
M. Doneus ◽  
G. Verhoeven ◽  
M. Fera ◽  
Ch. Briese ◽  
M. Kucera ◽  
...  
Keyword(s):  
Computer Vision ◽  
Point Cloud ◽  
Laser Scanning ◽  
Stereo Matching ◽  
Low Cost ◽  
Control Points ◽  
Positional Accuracy ◽  
3D Surface ◽  
Surface Models ◽  
Archaeological Excavations

Stratigraphic archaeological excavations demand high-resolution documentation techniques for 3D recording. Today, this is typically accomplished using total stations or terrestrial laser scanners. This paper demonstrates the potential of another technique that is low-cost and easy to execute. It takes advantage of software using Structure from Motion (SfM) algorithms, which are known for their ability to reconstruct camera pose and threedimensional scene geometry (rendered as a sparse point cloud) from a series of overlapping photographs captured by a camera moving around the scene. When complemented by stereo matching algorithms, detailed 3D surface models can be built from such relatively oriented photo collections in a fully automated way. The absolute orientation of the model can be derived by the manual measurement of control points. The approach is extremely flexible and appropriate to deal with a wide variety of imagery, because this computer vision approach can also work with imagery resulting from a randomly moving camera (i.e. uncontrolled conditions) and calibrated optics are not a prerequisite. For a few years, these algorithms are embedded in several free and low-cost software packages. This paper will outline how such a program can be applied to map archaeological excavations in a very fast and uncomplicated way, using imagery shot with a standard compact digital camera (even if the ima ges were not taken for this purpose). Archived data from previous excavations of VIAS-University of Vienna has been chosen and the derived digital surface models and orthophotos have been examined for their usefulness for archaeological applications. The a bsolute georeferencing of the resulting surface models was performed with the manual identification of fourteen control points. In order to express the positional accuracy of the generated 3D surface models, the NSSDA guidelines were applied.  Simultaneously acquired terrestrial laser scanning data – which had been processed in our standard workflow – was used to independently check the results. The vertical accuracy of the surface models generated by SfM was found to be within 0.04 m at the 95 % confidence interval, whereas several visual assessments proved a very high horizontal positional accuracy as well.

Forest road quality control using ALS data

2015 ◽  
Vol 45 (11) ◽  
pp. 1636-1642 ◽  
Author(s):  
Katalin Kiss ◽  
Jukka Malinen ◽  
Timo Tokola
Keyword(s):  
Laser Scanning ◽  
Road Surface ◽  
Airborne Laser Scanning ◽  
Forest Roads ◽  
Forest Road ◽  
Topographic Position ◽  
The Road ◽  
Topographic Position Index ◽  
Airborne Laser ◽  
Position Index

Good road conditions are necessary for the smooth transportation of forest machines and products. High-density airborne laser scanning data were used here to determine the quality of road surfaces and ditching systems. Forest roads in Kiihtelysvaara, Finland, were assessed in August 2013. Eight categories (structural condition, seasonal damage, drying, bridges, surface wear, visibility, coppicing, and flatness) have been inventoried and divided into three quality classes: poor, satisfactory, and good. The topographic position index, standardize elevation index, and hydrology tools were used on digital elevation models with different resolutions to test which categories could be derived. The road surface quality was most clearly related to surface wearing and flatness, and the topographic position index described the road surface best at resolutions of 0.20 m and 0.25 m; however, the standardized elevation index was superior at a 0.50 m resolution. The ditching system plays an important role in the drying of roads, and the hydrological tools and land facet analysis were most suitable for identifying the location of ditches and assessing their quality at 0.20 m and 0.25 m resolutions, respectively. The road surface was classified in all resolutions at least 66% correctly, whereas the ditches were classified in all resolutions at least 60% correctly. The results confirm that airborne laser scanning data can be used for obtaining quality information on forest roads.

scholarly journals Underwater High-Precision 3D Reconstruction System Based on Rotating Scanning

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1402
Author(s):  
Qingsheng Xue ◽  
Qian Sun ◽  
Fupeng Wang ◽  
Haoxuan Bai ◽  
Bai Yang ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
High Precision ◽  
Laser Scanning ◽  
Low Cost ◽  
Three Dimensional ◽  
Reconstruction Error ◽  
Scanning System ◽  
Standard Sphere ◽  
Underwater Camera ◽  
The Impact

This paper presents an underwater high-precision line laser three-dimensional (3D) scanning (LLS) system with rotary scanning mode, which is composed of a low illumination underwater camera and a green line laser projector. The underwater 3D data acquisition can be realized in the range of field of view of 50° (vertical) × 360° (horizontal). We compensate the refraction of the 3D reconstruction system to reduce the angle error caused by the refraction of light on different media surfaces and reduce the impact of refraction on the image quality. In order to verify the reconstruction effect of the 3D reconstruction system and the effectiveness of the refraction compensation algorithm, we conducted error experiments on a standard sphere. The results show that the system’s underwater reconstruction error is less than 0.6 mm within the working distance of 140 mm~2500 mm, which meets the design requirements. It can provide reference for the development of low-cost underwater 3D laser scanning system.

Middle of the road: enhanced habitat for salamanders on unused logging roads

2017 ◽  
Vol 44 (1) ◽  
pp. 1 ◽  
Author(s):  
David L. LeGros ◽  
Brad Steinberg ◽  
David Lesbarrères
Keyword(s):  
Woody Debris ◽  
Low Cost ◽  
Significant Proportion ◽  
Survey Method ◽  
Population Declines ◽  
Forest Roads ◽  
Forest Road ◽  
The Road ◽  
Field Season ◽  
Negative Impacts

Context Amphibians are particularly susceptible to the effects of habitat loss and fragmentation. The construction and use of roads is among the most common sources of habitat fragmentation and can lead to serious population declines. Unused resource access roads, such as those formerly used for logging, can still negatively impact salamanders and reduce habitat quality through edge effects. Unfortunately, habitat rehabilitation and enhancement is rarely attempted on unused forest roads. Aims Our aim was to elaborate on a previous study that tested several types of woody debris to mitigate the negative impacts of forest roads by creating a novel habitat on an unused forest road in Algonquin Provincial Park. Here we focus solely on the use of large, squared timbers and their use by salamanders. Methods We tested the application of coarse woody debris (CWD) to the surface of an unused forest road. CWD were sampled for salamanders seven times during the 2011 field season. Local climatic variables were tested against salamander captures, and CWD size preferences and patterns of salamander aggregation under CWD were assessed. Key results We observed five salamander species and 415 individuals under timbers in the 2011 field season. Larger timbers (>1m3) were preferred by all species observed and a significant proportion of animals were found in groups of two or more under larger timbers. High ambient temperature and low relative humidity negatively affected the number and species composition observed under timbers, suggesting that the efficiency of CWD as a survey method and enhanced habitat is season dependent. Implications Large timbers placed on unused forest roads may provide suitable refuges for migrating or dispersing forest salamanders while they attempt to cross the road. The tendency of salamanders to aggregate under CWD allows individual red efts to reduce water loss; however, red-backed salamanders are territorial and may drive off conspecifics. The use of large CWD may be an effective and low-cost method to rehabilitate unused forest roads and can be used to promote habitat connectivity for salamanders in targeted habitats, such as near wetlands, or for other species of concern.

Control Cloud Data Access Privilge Anonymity with Attributed Based Encryption

2017 ◽  
Vol 7 (8) ◽  
pp. 279
Author(s):  
P. Sudheer ◽  
T. Lakshmi Surekha
Keyword(s):  
Data Privacy ◽  
Low Cost ◽  
Data Access ◽  
Privacy Concerns ◽  
Cloud Data ◽  
Computing Paradigm ◽  
Attribute Based Encryption ◽  
Data Content ◽  
Identity Privacy ◽  
Cloud Servers

Cloud computing is a revolutionary computing paradigm, which enables flexible, on-demand, and low-cost usage of computing resources, but the data is outsourced to some cloud servers, and various privacy concerns emerge from it. Various schemes based on the attribute-based encryption have been to secure the cloud storage. Data content privacy. A semi anonymous privilege control scheme AnonyControl to address not only the data privacy. But also the user identity privacy. AnonyControl decentralizes the central authority to limit the identity leakage and thus achieves semi anonymity. The  Anonymity –F which fully prevent the identity leakage and achieve the full anonymity.

BUNUK: PENGETAHUAN DAN PRAKTEK ATONI-METO DALAM TATA KELOLA HUTAN

2019 ◽  
Vol 10 (1) ◽  
pp. 83-96
Author(s):  
Yohanes Victor Lasi Usbobo
Keyword(s):  
Forest Management ◽  
Indigenous People ◽  
Sustainable Forest Management ◽  
Customary Law ◽  
Environmental Damage ◽  
Technical Knowledge ◽  
Community Members ◽  
The Earth ◽  
Knowledge And Practice ◽  
West Timor

The implementation of todays forest management that based on formal-scientific knowledge and technical knowledge seems to fail to protect the forest from deforestation and the environmental damage. Decolonialisation of western knowledge could give an opportunity to identify and find the knowledge and practices of indigenous people in sustainable forest management. Forest management based on the indigenous knowledge and practices is believed easy to be accepted by the indigenous community due to the knowledge and practice is known and ‘lived’ by them. The Atoni Pah Meto from West Timor has their own customary law in forest management that is knows as Bunuk. In the installation of Bunuk, there is a concencus among the community members to protect and preserve the forest through the vow to the supreme one, the ruler of the earth and the ancestors, thus, bunuk is becoming a le’u (sacred). Thus, the Atoni Meto will not break the bunuk due to the secredness. Adapting the bunuk to the modern forest management in the Atoni Meto areas could be one of the best options in protecting and preserving the forest.

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