Figure 4 - uploaded by Ville Kankare
Content may be subject to copyright.
The principle of terrestrial laser scanning (TLS): TLS data are collected from a fixed-positioned tripod within the target area. A typical commercial TLS scanner rotates 180 degrees horizontally and 310 degrees vertically (top-right corner), providing full coverage of the surrounding area in a short time frame. A high-detail 3D point cloud (x, y, z, intensity) is recorded based on the emitted pulses reflected from the target surfaces visible to the scanner.
Source publication
The precise knowledge of forest structural attributes, such as biomass, logging recoveries and quality of the available timber, play an essential role in decision-making, forest management procedure planning and in wood supply chain optimization. Remote sensing-aided mapping applications are used intensively to acquire required forest resource info...
Contexts in source publication
Context 1
... data are most often collected from fixed-positioned tripods within the target area. Targets surrounding the static measurement location are recorded as 3D points (x, y, z and intensity) reflected from the target surfaces visible to the scanner (see Figure 4). TLS distance measurement is based on either phase shift or time-of-flight measurements. ...
Context 2
... showed that DBH accuracy decreased if tree density (trees/ha) increases. Highest accuracies were found in old- growth forests (tree densities less than 500/ha, Figure 14). MS-STI resulted in the best accuracies in Norway spruce-dominated forests (RMSE of 29.9 mm). ...
Similar publications
During the past decade, airborne laser scanning (ALS) has established its status as the state-of-the-art method for detailed forest mapping and monitoring. Current operational forest inventory widely utilizes ALS-based methods. Recent advances in sensor technology and image processing have enabled the extraction of dense point clouds from digital s...
Airborne laser scanning (ALS) is a reliable source of accurate information for forest stand inventory attributes including height, cover, basal area, and volume. The commonly applied area-based approach (ABA) allows the derivation of wall-to-wall geospatial coverages representing each of the modeled attributes at a grid-cell level, with spatial res...
Optical 2D remote sensing techniques such as aerial photographing and satellite imaging have been used in forest inventory for a long time. During the last 15 years, airborne laser scanning (ALS) has been adopted in many countries for the estimation of forest attributes at stand and sub-stand levels. Compared to optical remote sensing data sources,...
Abstract. The estimation of forest using Airborne Laser Scanning (ALS) data as auxiliary information has advanced substantially after more than three decades of studies. Numerous experiences have confirmed the potential of ALS data for the estimation of aggregated attributes such as volume, basal area or dominant height, and have developed methodol...
Citations
... Two segments can be distinguished, making up the ALS system: airborne and ground-based. The airborne system includes a laser range finder, a trajectory positioning system based on GPS (Global Positioning System), an inertial navigation system, a camera, a data logging block, and a flight planning and management system [26][27][28]. The ground part of the ALS includes a GPS reference station and a workstation for processing and generating the resulting products. ...
... agement system [26][27][28]. The ground part of the ALS includes a GPS reference station an a workstation for processing and generating the resulting products. ...
Modern technologies, such as airborne laser scanning (ALS) and advanced data analysis algorithms, allow for the efficient and safe use of resources to protect infrastructure from potential threats. This publication presents a study to identify trees that may fall on highways. The study used free measurement data from airborne laser scanning and wind speed and direction data from the Institute of Meteorology and Water Management in Poland. Two methods were used to determine the crown tops of trees: PyCrown and OPALS. The effect of wind direction on potential hazards was then analyzed. The OPALS method showed the best performance in terms of detecting trees, with an accuracy of 74%. The analysis showed that the most common winds clustered between 260° and 290°. Potential threats, i.e., trees that could fall on the road, were selected. As a result of the analysis, OPALS detected between 140 and 577 trees, depending on the chosen strategy. The presented research shows that combining ALS technology with advanced algorithms and wind data can be an effective tool for identifying potential hazards associated with falling trees on highways.
... As a new type of remote sensing platform developed in recent years, Unmanned Aerial Vehicle (UAV) has the advantages of lower data acquisition cost and higher spatial resolution than satellite remote sensing platforms (Wallace et al., 2012). Visible band images captured by UAVs can be used to construct estimation models of CV for different tree crown shapes (Huang et al., 2013;Kankare et al., 2013;Kankare, 2015). Besides, the 3D biometrical parameters of urban vegetation can be explored by using point clouds, a product of Light Detection and Ranging (LiDAR) (Lin et al., 2017;Zięba-Kulawik, 2021). ...
Street trees provide significant and widespread environmental benefits to the city and its citizens, such as improved air quality and adaptation to climate change. Crown volume (CV) indicates the geometric volume of crown, which is an essential indicator for the ecological service evaluation of street trees. The measurement of CV makes it possible to assess the carbon storage and input cost of urban trees. Because of the particularity of crown shape of street trees, the existing two-dimensional methods of calculating CV of forest trees become difficult except the three-dimensional techniques through the unmanned aerial vehicle, LiDAR equipment, and traditional harvest methods. In this study, a new virtual research method for plane calculation of angle disparity (PCAD) is proposed to calculate the CV of street trees. Two temporal satellite images of the exact location were first collected from Google Earth Pro, and then the angle disparity of images was adopted as a starting point to calculate tree height. Finally, CV was calculated from tree height, stem height, and crown diameter. The feasibility of the method was verified by a sample survey of street trees in Shanghai, China and the relative error of CV calculation by PCAD compared to that by field survey was 17.31 %. PCAD has the advantages of low-cost, quick operation, and suitability for a large area in studying CV of street trees.
... TLS is used in many fields, ranging from civil engineering, forestry, forensics, to open-pit and underground mining (e.g. Pagounis et al. 2006, Dassot et al. 2011, Kankare 2015, Lipecki, Thi Thu Huong 2020, Kekeç et al. 2021, Wu et al. 2022, Kumar Singh et al. 2023. It also finds applications in geology, where it offers much broader possibilities than just structural characterization of geological sites. ...
The results from two methods of structural analysis of the morphological rock escarpment are presented – a conventional technique, based on cartographic projection and set of structural measurements, and one based on processed point cloud data obtained from terrestrial laser scanning of the site (TLS). The results refer to one of the numerous sites located at the base of the nearly 40 km long vertical rock cliff (Radków Bluff) in Table Mountains, which locally reaches height of up to 50 m. The selected site in the area of so-called Radków Rocky Towers area is characterized by a complex and multi-stage structural pattern. A method of automatic and semi-automatic determination of discontinuity surfaces in the entire exposure was tested, with particular emphasis on zones of load induced fractures located at the base of the rock wall. The authors obtained a high convergence of the results generated from the point cloud analysis and those made by the traditional method using a geological compass. The paper suggests a correct and effective methodology for surveying and using data, as well as highlighting the benefits of documenting geological sites with the use of TLS. The analysis confirms the role and importance of fractures induced by a localized load in the process of destruction and retreat of morphological slopes.
... Ma et al. [37] used TLS forest point cloud data and improved the k-means clustering method to extract the DBH of trees. Kankare [38] used TLS to obtain singletree point cloud data, extract single-tree height, crown width, and other parameters, and established a singletree biomass model. Tilly et al. [39] used TLS to obtain maize point cloud data, generate a crop surface model, and measure maize plant height. ...
Background
The number of banana plants is closely related to banana yield. The diameter and height of the pseudo-stem are important morphological parameters of banana plants, which can reflect the growth status and vitality. To address the problems of high labor intensity and subjectivity in traditional measurement methods, a fast measurement method for banana plant count, pseudo-stem diameter, and height based on terrestrial laser scanning (TLS) was proposed.
Results
First, during the nutritional growth period of banana, three-dimensional (3D) point cloud data of two measured fields were obtained by TLS. Second, the point cloud data was preprocessed. And the single plant segmentation of the canopy closed banana plant point cloud was realized furtherly. Finally, the number of banana plants was obtained by counting the number of pseudo-stems, and the diameter of pseudo-stems was measured using a cylindrical segmentation algorithm. A sliding window recognition method was proposed to determine the junction position between leaves and pseudo-stems, and the height of the pseudo-stems was measured. Compared with the measured value of artificial point cloud, when counting the number of banana plants, the precision,recall and percentage error of field 1 were 93.51%, 94.02%, and 0.54% respectively; the precision,recall and percentage error of field 2 were 96.34%, 92.00%, and 4.5% respectively; In the measurement of pseudo-stem diameter and height of banana, the root mean square error (RMSE) of pseudo-stem diameter and height of banana plant in field 1 were 0.38 cm and 0.2014 m respectively, and the mean absolute percentage error (MAPE) were 1.30% and 5.11% respectively; the RMSE of pseudo-stem diameter and height of banana plant in field 2 were 0.39 cm and 0.2788 m respectively, and the MAPE were 1.04% and 9.40% respectively.
Conclusion
The results show that the method proposed in this paper is suitable for the field measurement of banana count, pseudo-stem diameter, and height and can provide a fast field measurement method for banana plantation management.
... Principiul de măsurare «time of flight» este același cu cel utilizat în scanarea laser aeriană (ALS). Precizia măsurării distanței în TLS prin «phase-shift» este mai precisă decât TLS cu «time of flight», dar distanța maximă este mai scurtă (Kankare, 2015). ...
... mai o singură stație de scanare (Liang et al., 2012), dar norul de puncte rezultat este incomplet în majoritatea cazurilor datorită ocluziei, ce creează dificultăți la detectarea arborilor și modelarea trunchiurilor. Ocluzia este cauzată de existența lemnului mort, desimea ridicată și prezența subarboretului în imediata apropiere a locului de scanare (Kankare, 2015). ...
... Estimarea biomasei coroanei arborilor reprezintă un subiect de mare interes pentru inginerii silvici și pentru cercetători. Măsurătorile cheie sunt focalizate pe diametrul la înălțimea pieptului (în continuare, dbh) și înălțimea totală a arborilor, uneori împreună cu un alt diametru suplimentar (Kankare, 2015). Înălțimea și dbh sunt apoi transformate în volum sau în biomasă folosind ecuații altitudinale predefinite (de ex. ...
TLS is also known as ground-based LiDAR which provides the capacity to recreate the 3D vegetation structure with millimeter accuracy. The distance
measurement of terrestrial laser scanner Z+F Imager 5010 is based on phase shift measurements which is more accurate than time of flight TLS. The time required
for a single scan varies according to the resolution needed. In forestry, TLS is used for the detailed structured modelling of plots and individual trees. Terrestrial laser scanning of trees has been seen as the best alternative to indirect and direct (destructive) measurements of volume. TLS technique provides accurate estimates the location, DBH and tree height from point cloud and besides these measurements
can be determined the volume on segments, commercial volume or crown volume.The quality of these metrics depends on the original scan data and their co-registration. We have done TLS measurements in six plots from FundivEurope research project with different slopes, tree density and species composition. The measurements allow us to identify which are advantages and disadvantages of using TLS in forest inventory, but in particular this study draws the attention to the precautions required for an accurate TLS use in biomass estimation.
... In this study, flat reference targets were positioned on both sides of the road. For a more detailed description of co-registration with reference targets, see, e.g., Kankare (2015). The registration accuracy of the final point cloud was approximately 5 mm (Fig. 3). ...
Corresponding author at: University of Helsinki, Department of Forest Sciences, P.O. Box 27 (Latokartanonkaari 7) FI-00014, Finland.
Assessment of the amount of carbon sequestered and the value of ecosystem services provided by urban trees requires reliable data. Predicting the proportions and allometric relationships of individual urban trees with models developed for trees in rural forests may result in significant errors in biomass calculations. To better understand the differences in biomass accumulation and allocation between urban and rural trees, two existing biomass models for silver birch (Betula pendula Roth) were tested for their performance in assessing the above-ground biomass (AGB) of 12 urban trees. In addition, the performance of a volume-based method utilizing accurate terrestrial laser scanning (TLS) data and stem density was evaluated in assessing urban tree AGB. Both tested models underestimated the total AGB of single trees, which was mainly due to a substantial underestimation of branch biomass. The volume-based method produced the most accurate estimates of stem biomass. The results suggest that biomass models originally based on sample trees from rural forests should not be used for urban, open-grown trees, and that volume-based methods utilizing TLS data are a promising alternative for non-destructive assessment of urban tree AGB.
There is a need for fast and automatic collection of forest data to support climate mitigation actions. Advancing methodologies, such as tree species recognition, is important to make best use of these data. Over the last four decades, advances in remote sensing technology have enabled the classification of tree species from several sensor types, such as Light Detection And Ranging (LiDAR). There is, however, a limited number of LiDAR-only studies related to tree species recognition. Recently, there has been a significant advancement in the use of Terrestrial Laser Scanning (TLS) from which a far more detailed forest structure can be obtained compared to traditional forest inventory methods. In fact, Quantitative Structure Models (QSMs), which are essentially models of trees constructed by fitting cylinders to the TLS point cloud, have been succesfully used to accurately determine important structural forest attributes.
This study used QSMs to examine the possibility of tree species classification from TLS data. 17 structural features were extracted from the QSMs of a 1.4 hectare deciduous forest plot in Wytham Woods (UK). The five main species, Acer pseudoplatanus (ACERPS), Fraxinus excelsior (FRAXEX), Corylus avellana (CORYAV), Crataegus monogyna (CRATMO) and Quercus robur (QUERRO), were considered. The potential of these features for tree species classification was statistically examined and discussed. Also the underlying causes for the stuctural differences were assessed with principal component analysis (PCA). Subsequently, 758 trees were classified using nested cross validation and several classification methods. More specifically, k-nearest neighbors (KNN)-, multinomial logistic regression (MLR)-, support vector machine (SVM)- and randomized forest (RF)-classifiers were applied.
Feature evaluation and principal component analysis showed structural similarity between species belonging to the same canopy class and shade tolerance group. These results support the theory that canopy class and shade tolerance lead to a convergence of structural tree traits across species. This convergence makes species classification more difficult due to decreased between-species variability. Concerning the classification performance and best classification method, it can be argued that this greatly depends on the application. Mean test accuracies around 80% are achieved while species-specific accuracies only range from 0 to 60% for three of the five species. A trade-off can be made to improve these species specific accuracies obtaining more than 50% for all species. However, this improvement is still limited by the structural similarities between the species and possibly by the small number of samples for some of the species. Nevertheless, this study proves the added value of TLS for tree species classification and ecological studies on the structure of tree species.
Terrestrial laser scanning (TLS) is a vital technique for collecting data with millimetre-level detail from the surrounding forest or individual trees. The downside of the technique is the vast amount of data it can collect, which requires efficient data processing methods. An increasing number of manual and automatic methods have been developed in recent years and most of them use point cloud sampling to fasten the processing. The challenge in the sampling procedures is the point density of TLS, which decreases rapidly as a function of distance from the scanner location. Therefore, traditional sampling procedures are not suitable for processing TLS point clouds. The present study focuses on evaluating two sampling procedures (presented in Puttonen et al. 2013) that aim to reduce the point density without losing the characteristics of the full point cloud. The study goal was to assess the effect of these two sampling procedures in tree detection and diameter at breast height (1.3 m, DBH) measurement accuracies in two sample cases. The results demonstrated that the point cloud sampling could be effectively used without losing accuracy in tree detection. However, for measurement of single-tree attributes, the use of full point cloud is recommended. Further evaluation of the methods is required with more diverse data set and due to the manual processing applied here. The automatic approach is mandatory if the approach is to be considered for more operational use.
