Prehliadanie podľa Autor "Skladan, Michal"
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Položka A low-cost MLS prototype for voxel-based above-ground biomass estimation in short-rotation plantations(Frontiers Media S.A. : Lausanne, 2025) Skladan, Michal; Singh, Arunima; Chudá, Juliána; Lieskovský, Martin; Masný, Matej; Výbošťok, JozefShort-rotation plantations of fast-growing trees (FGT) offer a sustainable biomass source to mitigate climate change and boost rural energy self-sufficiency. Accurate estimation of woody above-ground biomass (AGB) is critical for efficient management and utilization of these plantations. This study evaluates modern mobile laser scanning (MLS) techniques for dry-weight AGB estimation, comparing a commercial MLS system with a low-cost prototype built on the Livox Mid-360 sensor. Research was carried out in a dense, second-rotation poplar clone plantation. Thirty-one research plots were scanned using both MLS setups, then harvested and oven-dried to obtain reference dry weights. Point clouds were processed via a voxel-based approach at four resolutions (5, 10, 15 and 20 cm) to develop regression models correlating total voxel volume with dry biomass. The low-cost prototype delivered its best performance at 5 cm voxel size (R2 = 0.84; rRMSE = 12.2%), markedly outperforming the commercial system at the same resolution (R2 = 0.68; rRMSE = 17.5%). The commercial MLS achieved its optimum at 20 cm voxels (R2 = 0.82; rRMSE = 12.9%). Predictive models were validated using 16 plots for training and 15 for testing. The prototype yielded the highest precision for dry weight prediction (R2 = 0.89; rRMSE = 12.9%) at 5 cm resolution, while the commercial MLS excelled in fresh-weight estimation at 15 cm resolution (R2 = 0.92; rRMSE = 12.0%). These results demonstrate that affordable MLS solutions can provide biomass estimates comparable to those of higher-cost systems for dry AGB assessment in high-density poplar stands. Implementing low-cost laser scanning improves monitoring frequency, reduces operational expenses, and enables large-scale application in short-rotation forestry. This approach supports evidence-based decision-making for sustainable bioenergy production. Future work will explore integrating multispectral data and automated processing pipelines to further enhance biomass estimation accuracy and scalability across diverse forest conditions.Položka Assessment of new techniques for measuring volume in large wood chip piles(Multidisciplinary Digital Publishing Institute : Basel, 2024) Gejdoš, Miloš; Výbošťok, Jozef; Chudá, Juliána; Tomčík, Daniel; Lieskovský, Martin; Skladan, Michal; Masný, Matej; Gergeľ, TomášOur work aimed to compare the chip pile volumes calculated by laser ground scanning, UAV technology, and laser ground measurement and also to determine the accuracy, speed, and economic efficiency of each method. The large chip pile was measured in seven different ways: band measurement, laser measurement with Vertex, global navigation satellite system, handheld mobile laser scanner, terrestrial laser scanner, drone, and smartphone with a light detection and ranging sensor. All the methods were compared in terms of accuracy, price, user-friendliness, and time required to obtain results. The calculated pile volume, depending on the method, varied from 2588 to 3362 m3. The most accurate results were provided by the terrestrial laser scanning method, which, however, was the most expensive and the most demanding in terms of collecting and evaluating the results. From a time and economic point of view, the most effective methods were UAVs and smartphones with LiDAR.Položka Choosing the right close-range technology for measuring DBH in fast-growing trees plantations(Amsterdam : Elsevier B.V., 2025) Skladan, Michal; Chudá, Juliána; Singh, Arunima; Masný, Matej; Lieskovský, Martin; Pástor, Michal; Mokroš, Martin; Výbošťok, JozefRecently, the cultivation of fast-growing tree (FGT) plantations has gained importance due to the growing energy and climate crisis. FGT plantations have the potential to reduce carbon footprints and lower greenhouse gas emissions by utilization of local renewable energy sources. Effective monitoring of above-ground biomass (AGB) is crucial for the successful management of these plantations. Standard methods for estimating AGB rely on easily measurable parameters, such as Diameter at Breast Height (DBH) and tree height, which are highly correlated with AGB. Traditional methods for measuring DBH include measuring tapes and calipers; however, these techniques can be labor-intensive, time-consuming, and limited when assessing large areas. Innovative approaches, such as photogrammetry, terrestrial laser scanning (TLS), mobile laser scanning (MLS), and iPhone LiDAR scanning, can complement these traditional methods by generating point clouds that can be used for extracting dendrometric parameters. This study evaluates the effectiveness of TLS (RIEGL VZ-1000), MLS (Stonex X120 GO), iPhone LiDAR (iPhone 13 Pro MAX), and terrestrial photogrammetry (iPhone 13 Pro MAX) for estimating DBH in a Paulownia plantation. Each technology has limitations: while TLS offers high accuracy, it is also expensive and time-consuming. Similarly, MLS is relatively costly. On the other hand, iPhone LiDAR and terrestrial photogrammetry are more affordable alternatives; however, the iPhone LiDAR has a limited scanning range, and photogrammetry requires considerable time and expertise for data collection and processing. The primary objective of this study was to evaluate these technologies based on their accuracy in DBH estimation, ease of use, data collection, processing time, and cost within the ideal conditions of a Paulownia plantation (characterized by the absence of understory, level ground, and uniform tree shape and spacing). The aim was to determine whether traditional methods could be replaced with more efficient, quicker, easier, and cost-effective alternatives. Results indicated that TLS, MLS, and photogrammetry provided similar DBH estimation accuracies, with root mean square error (RMSE) values between 0.7 and 0.72 cm and relative RMSE values between 2.87 % and 2.95 %. In contrast, the iPhone LiDAR was the least accurate, with an RMSE of 1.7 cm and an rRMSE of 6.96 %. This study demonstrates that all evaluated technologies offer sufficient accuracy for DBH estimation, although TLS and MLS capture additional parameters at a higher cost. Therefore, TLS is impractical for DBH estimation in plantation environments due to its high cost, time, and labor demands. While less expensive, terrestrial photogrammetry also requires significant time investment and operator expertise. Despite its cost, MLS achieved the best results among all the evaluated technologies and proved to be the fastest and relatively simple. If cost is a concern, the best solution for DBH estimation in an FGT plantation environment would be iPhone LiDAR scanning. It represents the most affordable option with satisfactory accuracy and ease of use.