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Al-Hanbali, Nedal 
  
ASSESSMENT OF A LASER SCANNING SYSTEM FOR DEFORMATION 
MEASUREMENTS 
N. N. Al-Hanbali!, S. El-Hakim?, W. F. Teskey?, R. S. Radovanovic? , M. A. Chapman* 
Surveying and Geomatics Eng. Dept., Al-Balqa Applied University, Jordan, 
nhanbali@index.com.jo 
* Visual Information Technology, National Research Council of Canada, 
Sabry.El-Hakim(@nre.ca. 
Geomatics Eng. Dept, Faculty of Engineering, The University of Calgary, Calgary, AB, Canada, 
wteskey@ucalgary.ca., rsradova@ucalgary.ca 
^Civil Engineering Department, Ryerson University, Toronto, ON, Canada, 
mchapman@acs.ryerson.ca 
KEY WORDS: Laser Scanning, Calibration, Digital Imaging, Accuracy, Industrial Metrology 
ABSTRACT 
The Laser Scanning System (LSS) is a leading-edge technology laser-based three-dimensional vision system. The LSS 
has the potential to be used for industrial metrology to produce fast and reliable three-dimensional information for 
machinery alignment monitoring applications. The goal of this paper is to asses and verify via lab testing the calibration 
procedure followed and the feasibility of using the LSS for monitoring three-dimensional deformations in close-range 
(*1.5 m) industrial applications. Two approached are presented in the paper as to asses the use of the LSS to measure 
three-dimensional movements in operating machinery. The first approach is based on using the LSS calibrated 
parameters to measure point movements, and the second one is based on using a local scaling approach to show 
deformation trends. The Lab test and on-site test results for both approached are summarized and discussed briefly in 
this paper. To achieve these goals, software were developed to provide the required tools to utilize the measuring 
system to produce good, reliable and precise results. The interface software to act as a link between the user's command 
from a PC-based machine and the LSS operating systems to be used for scanning and acquiring the required images is 
shown. The developed software for image analysis, processing, and digitization is also presented. 
1. INTRODUCTION 
In industrial metrology, machinery alignment monitoring need high deformation measurement precision (up to 
+0.1mm), and instruments that has the capabilities to monitor deformations or misalignments continuously (Continuous 
monitoring), see Teskey et. al. (1994, 1995). In such applications, there is a limited space around the machinery, and 
hence, a single station setup instrument would be suitable. Another favorable feature is the use of a non-contact 
measurement instrument. Further more, it would be very useful to reconstruct surfaces and show deformation trends on 
these surfaces employing vision for such applications in addition to measure precisely point movements or 
misalignments. 
The laser scanning technology has these capabilities and the potential to be utilized to show deformation trends on the 
surface of the machine as well as measure precisely point movements at any required position within the scanned field 
of view. Hence, the LSS has the potential to be used to monitor the thermal growth and the vibrations of operating 
machinery during startup or shutdown within such time interval. 
In this paper the next section deals with the capabilities and basic geometry of the Laser Scanning System (LSS). The 
third section briefs the developed software and its functionality. Section four summarizes the conducted tests and the 
deformation measurement results of the local scaling approach. 
Section five discusses the mathematical model and digital data interpretation for calibration purposes. The calibration 
approach used is based on least squares adjustment method using the unified approach, which integrates the constraint 
equations and weight constraints that are needed to stabilize the solution. Section six summarizes the calibration results 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000. 9