scholarly journals FAST AND ROBUST STEM RECONSTRUCTION IN COMPLEX ENVIRONMENTS USING TERRESTRIAL LASER SCANNING

2016 ◽  
Vol XLI-B3 ◽  
pp. 411-417 ◽  
Author(s):  
D. Wang ◽  
M. Hollaus ◽  
E. Puttonen ◽  
N. Pfeifer
Keyword(s):  
Laser Scanning ◽  
Sampling Rate ◽  
Terrestrial Laser Scanning ◽  
Computation Time ◽  
Sampling Technique ◽  
Federal State ◽  
Accurate Estimation ◽  
Complex Environments ◽  
Forest Research ◽  
Advanced Sampling

Terrestrial Laser Scanning (TLS) is an effective tool in forest research and management. However, accurate estimation of tree parameters still remains challenging in complex forests. In this paper, we present a novel algorithm for stem modeling in complex environments. This method does not require accurate delineation of stem points from the original point cloud. The stem reconstruction features a self-adaptive cylinder growing scheme. This algorithm is tested for a landslide region in the federal state of Vorarlberg, Austria. The algorithm results are compared with field reference data, which show that our algorithm is able to accurately retrieve the diameter at breast height (DBH) with a root mean square error (RMSE) of ~1.9 cm. This algorithm is further facilitated by applying an advanced sampling technique. Different sampling rates are applied and tested. It is found that a sampling rate of 7.5% is already able to retain the stem fitting quality and simultaneously reduce the computation time significantly by ~88%.

scholarly journals FAST AND ROBUST STEM RECONSTRUCTION IN COMPLEX ENVIRONMENTS USING TERRESTRIAL LASER SCANNING

2016 ◽  
Vol XLI-B3 ◽  
pp. 411-417
Author(s):  
D. Wang ◽  
M. Hollaus ◽  
E. Puttonen ◽  
N. Pfeifer
Keyword(s):  
Laser Scanning ◽  
Sampling Rate ◽  
Terrestrial Laser Scanning ◽  
Computation Time ◽  
Sampling Technique ◽  
Federal State ◽  
Accurate Estimation ◽  
Complex Environments ◽  
Forest Research ◽  
Advanced Sampling

Terrestrial Laser Scanning (TLS) is an effective tool in forest research and management. However, accurate estimation of tree parameters still remains challenging in complex forests. In this paper, we present a novel algorithm for stem modeling in complex environments. This method does not require accurate delineation of stem points from the original point cloud. The stem reconstruction features a self-adaptive cylinder growing scheme. This algorithm is tested for a landslide region in the federal state of Vorarlberg, Austria. The algorithm results are compared with field reference data, which show that our algorithm is able to accurately retrieve the diameter at breast height (DBH) with a root mean square error (RMSE) of ~1.9 cm. This algorithm is further facilitated by applying an advanced sampling technique. Different sampling rates are applied and tested. It is found that a sampling rate of 7.5% is already able to retain the stem fitting quality and simultaneously reduce the computation time significantly by ~88%.

scholarly journals Geomorphometric analysis of cave ceiling channels mapped with 3D terrestrial laser scanning

2016 ◽  
Author(s):  
Michal Gallay ◽  
Zdenko Hochmuth ◽  
Ján Kaňuk ◽  
Jaroslav Hofierka
Keyword(s):  
Laser Scanning ◽  
Methodological Approach ◽  
Three Dimensional ◽  
Terrestrial Laser Scanning ◽  
Scalar Fields ◽  
Complex Environments ◽  
Digital Elevation ◽  
Unique Manner ◽  
Elevation Model ◽  
Different Levels

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organised vertically in different levels. Studying such complex environments traditionally requires tedious mapping, however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterisation and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional scalar fields which is sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a three-dimensional entity therefore a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3D computer graphics which can be applied to study other 3-D geomorphological forms

scholarly journals Geomorphometric analysis of cave ceiling channels mapped with 3-D terrestrial laser scanning

2016 ◽  
Vol 20 (5) ◽  
pp. 1827-1849 ◽  
Author(s):  
Michal Gallay ◽  
Zdenko Hochmuth ◽  
Ján Kaňuk ◽  
Jaroslav Hofierka
Keyword(s):  
Laser Scanning ◽  
Methodological Approach ◽  
Terrestrial Laser Scanning ◽  
Scalar Fields ◽  
Complex Environments ◽  
New Methods ◽  
Digital Elevation ◽  
Unique Manner ◽  
Elevation Model ◽  
Different Levels

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

scholarly journals Assessment of handheld mobile terrestrial laser scanning for estimating tree parameters

2020 ◽  
Author(s):  
Cornelis Stal ◽  
Jeffrey Verbeurgt ◽  
Lars De Sloover ◽  
Alain De Wulf
Keyword(s):  
Laser Scanning ◽  
Sustainable Forest Management ◽  
Terrestrial Laser Scanning ◽  
Accurate Estimation ◽  
Acquisition Time ◽  
Data Sets ◽  
Alternative Technique ◽  
Estimation Model ◽  
Individual Tree ◽  
Airborne Laser

Abstract Sustainable forest management heavily relies on the accurate estimation of tree parameters. Among others, the diameter at breast height (DBH) is important for extracting the volume and mass of an individual tree. For systematically estimating the volume of entire plots, airborne laser scanning (ALS) data are used. The estimation model is frequently calibrated using manual DBH measurements or static terrestrial laser scans (STLS) of sample plots. Although reliable, this method is time-consuming, which greatly hampers its use. Here, a handheld mobile terrestrial laser scanning (HMTLS) was demonstrated to be a useful alternative technique to precisely and efficiently calculate DBH. Different data acquisition techniques were applied at a sample plot, then the resulting parameters were comparatively analysed. The calculated DBH values were comparable to the manual measurements for HMTLS, STLS, and ALS data sets. Given the comparability of the extracted parameters, with a reduced point density of HTMLS compared to STLS data, and the reasonable increase of performance, with a reduction of acquisition time with a factor of 5 compared to conventional STLS techniques and a factor of 3 compared to manual measurements, HMTLS is considered a useful alternative technique.

scholarly journals Coupling Terrestrial Laser Scanning with 3D Fuel Biomass Sampling for Advancing Wildland Fuels Characterization

2019 ◽  
Author(s):  
Eric Rowell ◽  
E. Louise Loudermilk ◽  
Christie Hawley ◽  
Scott Pokswinski ◽  
Carl Seielstad ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Wildland Fire ◽  
Fire Behavior ◽  
Terrestrial Laser Scanning ◽  
Sampling Technique ◽  
Fire Effects ◽  
Three Dimensions ◽  
Fine Scale ◽  
Field Sampling ◽  
Volume Porosity

AbstractThe spatial pattern of surface fuelbeds in fire-dependent ecosystems are rarely captured using long-standing fuel sampling methods. New techniques, both field sampling and remote sensing, that capture vegetation fuel type, biomass, and volume at super fine-scales (cm to dm) in three-dimensions (3D) are critical to advancing forest fuel and wildland fire science. This is particularly true for computational fluid dynamics fire behavior models that operate in 3D and have implications for wildland fire operations and fire effects research. This study describes the coupling of new 3D field sampling data with terrestrial laser scanning (TLS) data to infer fine-scale fuel mass in 3D. We found that there are strong relationships between fine-scale mass and TLS occupied volume, porosity, and surface area, which were used to develop fine-scale prediction equations using TLS across vegetative fuel types, namely grasses and shrubs. The application of this novel 3D sampling technique to high resolution TLS data in this study represents a major advancement in understanding fire-vegetation feedbacks in highly managed fire-dependent ecosystems.

scholarly journals Estimation of Pinus massoniana Leaf Area USING Terrestrial Laser Scanning

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 660 ◽  
Author(s):  
Yangbo Deng ◽  
Kunyong Yu ◽  
Xiong Yao ◽  
Qiaoya Xie ◽  
Yita Hsieh ◽  
...  
Keyword(s):  
Leaf Area ◽  
Point Cloud ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Pinus Massoniana ◽  
Accurate Estimation ◽  
Point Cloud Data ◽  
Individual Tree ◽  
Cloud Data ◽  
Non Destructive

The accurate estimation of leaf area is of great importance for the acquisition of information on the forest canopy structure. Currently, direct harvesting is used to obtain leaf area; however, it is difficult to quickly and effectively extract the leaf area of a forest. Although remote sensing technology can obtain leaf area by using a wide range of leaf area estimates, such technology cannot accurately estimate leaf area at small spatial scales. The purpose of this study is to examine the use of terrestrial laser scanning data to achieve a fast, accurate, and non-destructive estimation of individual tree leaf area. We use terrestrial laser scanning data to obtain 3D point cloud data for individual tree canopies of Pinus massoniana. Using voxel conversion, we develop a model for the number of voxels and canopy leaf area and then apply it to the 3D data. The results show significant positive correlations between reference leaf area and mass (R2 = 0.8603; p < 0.01). Our findings demonstrate that using terrestrial laser point cloud data with a layer thickness of 0.1 m and voxel size of 0.05 m can effectively improve leaf area estimations. We verify the suitability of the voxel-based method for estimating the leaf area of P. massoniana and confirmed the effectiveness of this non-destructive method.

scholarly journals Quantification of occlusions influencing the tree stem curve retrieving from single-scan terrestrial laser scanning data

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Peng Wan ◽  
Tiejun Wang ◽  
Wuming Zhang ◽  
Xinlian Liang ◽  
Andrew K. Skidmore ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Laser Scanning ◽  
Terrestrial Laser Scanning ◽  
Basal Area ◽  
Stem Volume ◽  
Accurate Estimation ◽  
Forest Plot ◽  
Curve Estimation ◽  
Standing Trees ◽  
Occlusion Rate

Abstract Background The stem curve of standing trees is an essential parameter for accurate estimation of stem volume. This study aims to directly quantify the occlusions within the single-scan terrestrial laser scanning (TLS) data, evaluate its correlation with the accuracy of the retrieved stem curves, and subsequently, to assess the capacity of single-scan TLS to estimate stem curves. Methods We proposed an index, occlusion rate, to quantify the occlusion level in TLS data. We then analyzed three influencing factors for the occlusion rate: the percentage of basal area near the scanning center, the scanning distance and the source of occlusions. Finally, we evaluated the effects of occlusions on stem curve estimates from single-scan TLS data. Results The results showed that the correlations between the occlusion rate and the stem curve estimation accuracies were strong (r = 0.60–0.83), so was the correlations between the occlusion rate and its influencing factors (r = 0.84–0.99). It also showed that the occlusions from tree stems were the main factor of the low detection rate of stems, while the non-stem components mainly influenced the completeness of the retrieved stem curves. Conclusions Our study demonstrates that the occlusions significantly affect the accuracy of stem curve retrieval from the single-scan TLS data in a typical-size (32 m × 32 m) forest plot. However, the single-scan mode has the capacity to accurately estimate the stem curve in a small forest plot (< 10 m × 10 m) or a plot with a lower occlusion rate, such as less than 35% in our tested datasets. The findings from this study are useful for guiding the practice of retrieving forest parameters using single-scan TLS data.

Sign in / Sign up

Export Citation Format

Share Document