@techreport{CremerBerendtdeMiguelDiezetal.2020, type = {Working Paper}, author = {Cremer, Tobias and Berendt, Ferr{\´e}ol and de Miguel Diez, Felipe and Wolfgramm, Felix and Blasko, Lubomir}, title = {Accuracy of Photo-Optical Measurement of Wood Piles}, series = {Environmental Sciences Proceedings}, journal = {Environmental Sciences Proceedings}, number = {3(1)}, publisher = {MDPI}, issn = {2673-4931}, doi = {10.3390/IECF2020-08192}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2012}, pages = {4}, year = {2020}, abstract = {The accurate estimation of timber volume is of the utmost importance. For industrial timber, the volume is often estimated as stacked cubic meters. In addition to manual measurements, volume estimation is possible with photo-optical systems. Over 100 piles of industrial timber of broadleaved tree species were analyzed. In the study, a standard manual measurement method for the estimation of wood pile volumes was compared with a smartphone based photo-optical application for the determination of woodpile volume. Mean gross volume of the piles was approximately 56 m3 and mean width of piles was 9.43 m. A strong correlation was found between the manual measurements and the photo-optical measurement. However, volume estimation of large volume piles seems to perform better in comparison to piles with small volumes. Further research is needed to determine the effects of variables such as log quality or quality of pile on volume estimation accuracy.}, language = {en} } @article{BerendtWolfgrammCremer2021, author = {Berendt, Ferr{\´e}ol and Wolfgramm, Felix and Cremer, Tobias}, title = {Reliability of photo-optical measurements of log stack gross volume}, series = {Silva Fennica}, volume = {55}, journal = {Silva Fennica}, number = {3}, issn = {2242-4075}, doi = {10.14214/sf.10555}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2003}, pages = {1 -- 13}, year = {2021}, abstract = {In terms of assessing economic impact, one of the most important elements in the wood supply chain is the measurement of round wood. Besides the one-by-one measurement of logs, logs are often measured when stacked at the forest road. The gross stacked volume includes the volume of the wood, bark and airspace and is widely used for industrial wood assortments. The increasing international attention given to photo-optical measurement systems for portable devices is due to their simplicity of use and efficiency. The aim of this study was to compare the gross volumes of hardwood log stacks measured using one widespread photo-optical app with two manual section-wise volume estimations of log stacks based on the German framework agreement for timber trade (RVR). The manual volume estimations were done starting from the left (RVRleft) and right (RVRright) sides of the log stacks. The results showed an average deviation of the photo-optical gross volume estimation in comparison to the manual estimation of -2.09\% (RVRleft) and -3.66\% (RVRright) while the deviation between RVRleft and RVRright was +2.54\%. However, the log stack gross volume had a highly significant effect on the deviation and better accuracy with smaller deviation were reached for larger log stacks. Moreover, results indicated that the gross volume estimations of higher quality log stacks were closer for the three analyzed methods compared to estimations of poor-quality log stacks.}, language = {en} }