Doctoral Dissertations

Keywords and Phrases

Rock face vegetation removal; Rock slope vegetation; Terrestrial LIDAR; Vegetation elimination; Virtual articulating conical probe; Without eroding underlying rock

Abstract

"A common use of terrestrial lidar is to conduct studies involving change detection of natural or engineered surfaces. Change detection involves many technical steps beyond the initial data acquisition: data structuring, registration, and elimination of data artifacts such as parallax errors, near-field obstructions, and vegetation. Of these, vegetation detection and elimination with terrestrial lidar scanning (TLS) presents a completely different set of issues when compared to vegetation elimination from aerial lidar scanning (ALS). With ALS, the ground footprint of the lidar laser beam is very large, and the data acquisition hardware supports multi-return waveforms. Also, the underlying surface topography is relatively smooth compared to the overlying vegetation which has a high spatial frequency. On the other hand, with most TLS systems, the width of the lidar laser beam is very small, and the data acquisition hardware supports only first-return signals. For the case where vegetation is covering a rock face, the underlying rock surface is not smooth because rock joints and sharp block edges have a high spatial frequency very similar to the overlying vegetation. Traditional ALS approaches to eliminate vegetation take advantage of the contrast in spatial frequency between the underlying ground surface and the overlying vegetation. When the ALS approach is used on vegetated rock faces, the algorithm, as expected, eliminates the vegetation, but also digitally erodes the sharp corners of the underlying rock. A new method that analyzes the slope of a surface along with relative depth and contiguity information is proposed as a way of differentiating high spatial frequency vegetative cover from similar high spatial frequency rock surfaces. This method, named the Virtual Articulating Conical Probe (VACP) algorithm, offers a solution for detection and elimination of rock face vegetation from TLS point cloud data while not affecting the geometry of the underlying rock surface. Such a tool could prove invaluable to the geotechnical engineer for quantifying rates of vertical-face rock loss that impact civil infrastructure safety"--Abstract, page iii.

Advisor(s)

Maerz, Norbert H.

Committee Member(s)

Rogers, J. David
Cawlfield, Jeffrey D.
Moss, Randy Hays, 1953-
Witt, Emitt C., III

Department(s)

Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geological Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2019

Pagination

xiv, 262 pages

Note about bibliography

Includes bibliographic references (pages 250-261).

Rights

© 2019 Kenneth John Boyko, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11519

Electronic OCLC #

1105154964

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