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Proceedings Paper

Image thresholding in the high resolution target movement monitor
Author(s): Randy H. Moss; Steve E. Watkins; Tristan H. Jones; Derek B. Apel; Deepti Bairineni
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Paper Abstract

Image thresholding in the High Resolution Target Movement Monitor (HRTMM) is examined. The HRTMM was developed at the Missouri University of Science and Technology to detect and measure wall movements in underground mines to help reduce fatality and injury rates. The system detects the movement of a target with sub-millimeter accuracy based on the images of one or more laser dots projected on the target and viewed by a high-resolution camera. The relative position of the centroid of the laser dot (determined by software using thresholding concepts) in the images is the key factor in detecting the target movement. Prior versions of the HRTMM set the image threshold based on a manual, visual examination of the images. This work systematically examines the effect of varying threshold on the calculated centroid position and describes an algorithm for determining a threshold setting. First, the thresholding effects on the centroid position are determined for a stationary target. Plots of the centroid positions as a function of varying thresholds are obtained to identify clusters of thresholds for which the centroid position does not change for stationary targets. Second, the target is moved away from the camera in sub-millimeter increments and several images are obtained at each position and analyzed as a function of centroid position, target movement and varying threshold values. With this approach, the HRTMM can accommodate images in batch mode without the need for manual intervention. The capability for the HRTMM to provide automated, continuous monitoring of wall movement is enhanced.

Paper Details

Date Published: 30 March 2009
PDF: 12 pages
Proc. SPIE 7292, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009, 72920G (30 March 2009); doi: 10.1117/12.815521
Show Author Affiliations
Randy H. Moss, Missouri Univ. of Science and Technology (United States)
Steve E. Watkins, Missouri Univ. of Science and Technology (United States)
Tristan H. Jones, Missouri Univ. of Science and Technology (United States)
Derek B. Apel, Missouri Univ. of Science and Technology (United States)
Univ. of Alberta (Canada)
Deepti Bairineni, Missouri Univ. of Science and Technology (United States)


Published in SPIE Proceedings Vol. 7292:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009
Masayoshi Tomizuka, Editor(s)

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