Change search
ReferencesLink to record
Permanent link

Direct link
X-ray measurement of properties of saw logs
Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
1999 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A nondestructive method of measuring knot parameters for research purposes has been compared to alternative, destructive methods. The method is based on automatic analysis of CT-images. The image analysis algorithms were adjusted to and evaluated on Norway spruce. The possibilities of measuring resin pockets in CT-images have been studied and stereological methods have been applied on volume estimation of resin pockets in saw logs. For research purposes the study showed that compared to destructive methods, both accuracy and speed of the CT-method were competitive. It was also shown that resin pockets can be detected and measured in CT-images of Norway spruce. Data from the CT-scanned logs was used to simulate an industrial X-ray LogScanner. The X-ray LogScanner was based on two X-ray sources and designed for scanning at 3 m/s. The possibility of using this X-ray LogScanner to make nondestructive measurements of properties of saw logs has been investigated. The study showed that the X-ray LogScanner measures minimum shadow diameter under bark before debarking with an accuracy comparable to a 3D-scanner and that the sawing position could be controlled based on X-ray LogScanner measurements of the best half of the logs. The X-ray LogScanner could also be used to measure percentage of heartwood and green heartwood density. Based on the X-ray LogScanner measurements it was possible to calibrate PLS-models for prediction of the bending stiffness of the centerboards.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 1999. , 38 p.
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544 ; 1999:14
Research subject
Wood Technology
URN: urn:nbn:se:ltu:diva-18763Local ID: a3021d40-86bc-11db-8975-000ea68e967bOAI: diva2:991774
Godkänd; 1999; 20061117 (haneit)Available from: 2016-09-29 Created: 2016-09-29Bibliographically approved

Open Access in DiVA

fulltext(56251 kB)10 downloads
File information
File name FULLTEXT01.pdfFile size 56251 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Oja, Johan
By organisation
Wood Science and Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 10 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 14 hits
ReferencesLink to record
Permanent link

Direct link