T165 Seeing the True Shape of Earth: Quantitative and Qualitative Applications of Airborne LiDAR

Tuesday, 11 October 2011
8:00 AM - 12:00 PM
Room 101DE

HIGH RESOLUTION PHOTOREALISTIC OUTCROP MODEL ACQUISITION, CONSTRUCTION, AND ANALYSIS

Paper number: T165-7
Program: Technical Sessions
Time: 9:35 AM – 9:50 AM

Authors

Abstract

Construction of photorealistic outcrop models requires multiple surveyed scans of the outcrops, rendering of the aligned point clouds as TIN mesh models, and draping of photographs onto the TIN mesh. Analysis of the models requires software that allows the user to interact with the model, analyze extracted points, and insert features back into the model representing the results. Two software suites have been developed to support these requirements.

The GeoConstructor suite combines control of a robotic total station and a camera mounted on a robotic pan-tilt unit to acquire photographs that are spatially registered to the outcrop. The software automatically drapes the photographs onto the TIN mesh model of the outcrop producing the photorealistic model. The photo alignment rms residuals are typically one pixel. The camera is independent of the scanner removing a limitation on the focal length of the lens. Using the orientation information from the scanner, GeoConstructor can drape photographs taken with a scanner mounted camera.

GeoAnalysisTools is an ESRI ArcScene extension that displays the photorealistic model in a 3D environment and enables the user to interact with the model. The software provides a number of analytical tools: strike-dip, down plunge cross-section, orthogonal bed thickness, delineation of bedding, and annotation of results.

Two large, high resolution models have been constructed over the past year. A model of the Jurassic Jubaila Formation (middle Arab D) on the outskirts of Riyadh was created with scans covering 4 km of outcrop and over eight hundred 24.5 megapixel photographs draped on the model providing optical resolutions to 1 mm per pixel. A Nikon D3X camera, 105 mm and 300 mm lenses, was used. A model of the Ordovician Quweira Formation in the Medain Saleh archeological area of NW Saudi Arabia was captured with scans covering over 2.5 km of outcrop and over 800 high resolution photos. The outcrop exceeded 80 m in height. Both outcrops were produced under a UTD contract with Saudi Aramco.