Full text of this article is only available in PDF format.

Jacob Edlund (email), Mats Warensjö

Repeatability in automatic sorting of curved Norway spruce saw logs

Edlund J., Warensjö M. (2005). Repeatability in automatic sorting of curved Norway spruce saw logs. Silva Fennica vol. 39 no. 2 article id 388. https://doi.org/10.14214/sf.388

Abstract

Sawn wood from curved logs is prone to have cross grain and contain compression wood, both of which affect the dimensional stability. Different types of curvature can, however, have different effects on both the sawing process and board quality, which is why a standard measure of bow height alone is not enough to sort logs or set the log quality. The aim of this study was to evaluate the repeatability when sorting curved saw logs using a 3D log scanner. In the study, 56 logs were categorized into five different curvature types and four different degrees of curvature severity. The logs were run through a Rema 3D log scanner four times, and the external geometry was recorded. From the geometry data, variables describing log shapes were calculated and used to develop models using linear discriminant analysis, which was used to classify the logs according to curvature type. The accuracy and repeatability were evaluated for the classifications with Cohen’s simple Kappa coefficient. The results of this study showed that it is possible to sort logs by curve type using a 3D log scanner, although sorting by curve type was largely dependent on curve severity. The repeatability test determined that the chance of a curved log being graded identically two consecutive times was 0.40, measured as kappa.

Keywords
Picea abies; compression wood; stem form; bow; scanner; sorting

Author Info
  • Edlund, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail jacob.edlund@spm.slu.se (email)
  • Warensjö, SLU, Department of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail mw@nn.se

Received 31 August 2004 Accepted 30 March 2005 Published 31 December 2005

Views 4165

Available at https://doi.org/10.14214/sf.388 | Download PDF

Creative Commons License CC BY-SA 4.0

Register
Click this link to register to Silva Fennica.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content

Your selected articles
Send to email
Finnish Society of Forest Science ., (1992) Instructions to authors. Silva Fennica vol. 26 no. 1 article id 5473 (remove) | Edit comment
Larjavaara M., Kuuluvainen T. et al. (2004) Variation in forest fire ignition probability in.. Silva Fennica vol. 38 no. 3 article id 414 (remove) | Edit comment
Ilvessalo Y., Ilvessalo M. (1975) The forest types of Finland in the light of natu.. Acta Forestalia Fennica vol. 0 no. 144 article id 7578 (remove) | Edit comment
Chaitanya K. S. K., Keshavkant S. et al. (2000) Changes in total protein and protease activity i.. Silva Fennica vol. 34 no. 1 article id 646 (remove) | Edit comment
Haapanen M., Annala M.-L. et al. (1997) Progeny trial estimates of genetic parameters fo.. Silva Fennica vol. 31 no. 1 article id 5605 (remove) | Edit comment
Your search results