@article{deMiguelDiezGuiguePettenkoferetal.2022, author = {de Miguel-D{\´i}ez, Felipe and Guigue, Phillippe and Pettenkofer, Tim and Tolosana-Esteban, Eduardo and Purf{\"u}rst, Thomas and Cremer, Tobias}, title = {Development and evaluation of a novel 3D simulation software for modelling wood stacks}, series = {PLoS ONE}, journal = {PLoS ONE}, number = {17(3)}, issn = {1932-6203}, doi = {10.1371/journal.pone.0264414}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4472}, pages = {17}, year = {2022}, abstract = {Assessing the solid wood content is crucial when acquiring stacked roundwood. A frequently used method for this is to multiply determined conversion factors by the measured gross volume. However, the conversion factors are influenced by several log and stack parameters. Although these parameters have been identified and studied, their individual influence has not yet been analyzed using a broad statistical basis. This is due to the considerable financial resources that the data collection entails. To overcome this shortcoming, a 3D-simulation model was developed. It generates virtual wood stacks of randomized composition based on one individual data set of logs, which may be real or defined by the user. In this study, the development and evaluation of the simulation model are presented. The model was evaluated by conducting a sensitivity and a quantitative analysis of the simulation outcomes based on real measurements of 405 logs of Norway spruce and 20 stacks constituted with these. The results of the simulation outcomes revealed a small overestimation of the net volume of real stacks: by 1.2\% for net volume over bark and by 3.2\% for net volume under bark. Furthermore, according to the calculated mean bias error (MBE), the model underestimates the gross volume by 0.02\%. In addition, the results of the sensitivity analysis confirmed the capability of the model to adequately consider variations in the input parameters and to provide reliable outcomes.}, language = {en} } @article{deMiguelDiezPettenkoferWalloretal.2022, author = {de Miguel-D{\´i}ez, Felipe and Pettenkofer, Tim and Wallor, Evelyn and Tolosana-Esteban, Eduardo and Purf{\"u}rst, Thomas and Cremer, Tobias}, title = {Influence of log and stack parameters on the conversion factors for Norway Spruce wood stacks using a 3D simulation model}, series = {International Journal of Forest Engineering}, volume = {33}, journal = {International Journal of Forest Engineering}, number = {2}, publisher = {Taylor \& Francis}, issn = {1494-2119}, doi = {10.1080/14942119.2022.2038023}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4482}, pages = {119 -- 128}, year = {2022}, abstract = {One method for estimating the solid wood content in a stack involves using conversion factors and multiplying these by the measured gross volume. The conversion factors can vary depending on several log and stack parameters. The aim of this study was to analyze eleven parameters using a 3D simulation model based on 541 measured logs of Norway spruce. To this end, 50 data sets were created from measured logs, where the parameters of interest in this study (e.g., length, crookedness, taper …) were classified according to different ranges. After that, 64 runs of simulations were carried out. In each simulation run, 150 stacks were modeled. The simulation results were compared with previous studies and with the measurement guidelines of several countries. This analysis revealed that the parameters midpoint diameter, length, crookedness, delimbing quality and the proportion of moderately and highly crooked logs in a stack have a considerable influence on the conversion factors. Taper, proportion of butt logs in a stack and stack height have a modest effect as do the proportion of tapered and crooked logs for low and high taper and low crookedness. In contrast, ovality and the proportion of logs stacked in opposite directions have a marginal influence on the conversion factors. Based on findings from these analyses, the current measurement guidelines of different countries can now be adapted to achieve a higher degree of accuracy.}, language = {en} } @article{deMiguelDiezRederWalloretal.2022, author = {de Miguel-D{\´i}ez, Felipe and Reder, Stefan and Wallor, Evelyn and Bahr, Henrik and Blasko, Lubomir and Mund, Jan-Peter and Cremer, Tobias}, title = {Further application of using a personal laser scanner and simultaneous localization and mapping technology to estimate the log's volume and its comparison with traditional methods}, series = {International Journal of Applied Earth Observation and Geoinformation}, journal = {International Journal of Applied Earth Observation and Geoinformation}, number = {109}, publisher = {Elsevier}, issn = {1872-826X}, doi = {10.1016/j.jag.2022.102779}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4496}, pages = {7}, year = {2022}, abstract = {The aim of this study was the development of a methodical processing line for estimating the log's volume from scanning logs using a long-range high-speed personal laser scanner (PLS) GeoSLAM ZEB HORIZON and simultaneous localization and mapping (SLAM) technology in an open-source software framework of Cloud Compare. Additionally, the accuracy and precision of using PLS and the suggested method when measuring roundwood volume was examined compared to measurements made using a xylometer and estimations obtained from applying the formulae of Huber, Smalian and Newton. For this purpose, several parameters were measured in 50 logs of Norway spruce with an average length of 2.53 m and a mean diameter of 19.97 cm. Afterwards, the volume of these 50 logs was measured with a xylometer. The results of these measurements served as reference values. The same 50 logs were subsequently scanned with the PLS. The scans were converted into point clouds and were analyzed in Cloud Compare to estimate the volume of the scanned logs. Next, the root mean square error (RMSE) and the mean bias error (MBE) as well as their relative values were calculated for the volumes determined in Cloud Compare and estimated with the above mentioned formulae. The calculated RMSE (and relative RMSE) determined a deviation of the logs' volumes estimated in Cloud Compare from the xylometric volumes of 2.88 dm3 (3.54\%) whereas the deviations of the log's volumes calculated applying the formulae of Huber, Smalian and Newton from the xylometric volumes were respectively 9.63 dm3 (11.83\%), 10.33 dm3 (12.69\%) and 4.69 dm3 (5.76\%). The calculated MBE (and relative MBE) showed that the estimated volumes in Cloud Compare and those using the formulae were overestimated, with the lowest overestimation of 0.10 dm3 (0.12\%) in Cloud Compare and the highest, 5.50 dm3 (6.75\%), using the Smalian formula. Therefore, it can be stated that results of suggested methodical processing line came closest to the logs' volumes obtained with the xylometer, i.e., they were more accurate and precise compared to the conventionally formulae for log's volume estimation. The implementation of this method has the potential filling a gap towards a wall-to-wall complete digitization of the roundwood commercialization and ensure transparency and acceptance between the stakeholders involved in the wood supply chain.}, language = {en} }