Investigating the use of LiDAR scanning as a method for the measurement of timber distortion features

Boney, Adam (2016) Investigating the use of LiDAR scanning as a method for the measurement of timber distortion features. MSc(R) thesis, University of Glasgow.

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Abstract

Measuring the extent to which a piece of structural timber has distorted at a macroscopic scale is fundamental to assessing its viability as a structural
component. From the sawmill to the construction site, as structural timber
dries, distortion can render it unsuitable for its intended purposes. This rejection of unusable timber is a considerable source of waste to the timber
industry and the wider construction sector. As such, ensuring accurate measurement of distortion is a key step in addressing ineffciencies within timber processing.
Currently, the FRITS frame method is the established approach used to
gain an understanding of timber surface profile. The method, while reliable,
is dependent upon relatively few measurements taken across a limited area of the overall surface, with a great deal of interpolation required. Further, the
process is unavoidably slow and cumbersome, the immobile scanning equipment limiting where and when measurements can be taken and constricting the process as a whole.
This thesis seeks to introduce LiDAR scanning as a new, alternative approach
to distortion feature measurement. In its infancy as a measurement
technique within timber research, the practicalities of using LiDAR scanning
as a measurement method are herein demonstrated, exploiting many of the
advantages the technology has over current approaches. LiDAR scanning creates a much more comprehensive image of a timber surface, generating input data multiple magnitudes larger than that of the FRITS frame. Set-up and scanning time for LiDAR is also much quicker and more flexible than existing methods. With LiDAR scanning the measurement process is freed from many of the constraints of the FRITS frame and can be done in almost any environment.
For this thesis, surface scans were carried out on seven Sitka spruce samples
of dimensions 48.5x102x3000mm using both the FRITS frame and LiDAR
scanner. The samples used presented marked levels of distortion and were
relatively free from knots. A computational measurement model was created
to extract feature measurements from the raw LiDAR data, enabling an assessment of each piece of timber to be carried out in accordance with existing standards. Assessment of distortion features focused primarily on the measurement of twist due to its strong prevalence in spruce and the considerable concern it generates within the construction industry. Additional measurements of surface inclination and bow were also made with each method to further establish LiDAR's credentials as a viable alternative.
Overall, feature measurements as generated by the new LiDAR method compared well with those of the established FRITS method. From these investigations recommendations were made to address inadequacies within existing measurement standards, namely their reliance on generalised and interpretative descriptions of distortion. The potential for further uses of LiDAR scanning within timber researches was also discussed.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Keywords: Timber, distortion, LiDAR, FRITS Frame.
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Colleges/Schools: College of Science and Engineering > School of Engineering
Supervisor's Name: de Borst, Dr. Karin
Date of Award: 2016
Depositing User: Mr Adam Boney
Unique ID: glathesis:2016-7583
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 04 Oct 2016 08:22
Last Modified: 21 Oct 2016 12:45
URI: http://theses.gla.ac.uk/id/eprint/7583

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