3D Laser Scanning
Three-dimensional (3D) laser scanners are a class of instruments that record very
precise and accurate surface data of objects in a non-destructive manner. Based on
LiDAR (Light Detection and
Ranging) technology, these instruments use an infrared beam
of light to calculate and record the distance to an object, typically as data points
with spatial coordinates. Given the speed of these instruments, large numbers of data
points can be collected quickly and at a high sampling interval, or density, across the
surface of an object to create a highly accurate 3D digital model. Sometimes referred to
as High Definition Survey (HDS), several types of 3D laser scanners exist to digitize
objects of various sizes ranging
from small diagnostic artifacts to large, complex sites of monumental architecture.
Since 2000, GMI has utilized 3D laser scanning to quickly and accurately record archaeological sites, historic architecture, and artifacts as high definition 3D computer models. These models, in turn, can be used for a number of purposes including documentation, visualization, and analysis.
For more information on the application of 3D laser scanning to archaeology, historic preservation, cultural heritage studies, or cultural resources management, see GMI’s 3D Laser Scanning Projects Portfolio and 3D Laser Scanning for CRM or contact Christopher Goodmaster, 3D Laser Scanning Specialist.
Project portfolio
Petroglyph Documentation Using Three-Dimensional Laser Scanning, Parks Canada and the Royal Alberta Museum
Writing-On-Stone
Provincial Park is located in south-central Alberta, Canada. The
park protects the largest concentration of native rock art on the
Great Plains. Geo-Marine, Inc., was subcontracted by the Royal
Alberta Museum to conduct a small test of the feasibility of using a
laser scanner device to record petroglyphs at Writing-On-Stone
Provincial Park. Fieldwork was conducted over two days on July 6 and
7, 2005, by a combined team of Geo-Marine, Royal Alberta Museum, and
Parks Canada employees.
The petroglyphs selected for this trial project record the prehistoric/historical-period cultural transition of southern Alberta. Two panels used for the current study are located on large sandstone cliffs. One small replica panel was also scanned.
GMI used a Vivid 900 non-contact 3D digitizer to conduct the scanning. Because the petroglyphs at Writing-On-Stone were extremely shallow and faint, Geo-Marine, Inc., scanned the rock surface in dozens of small, high-resolution shots, and then produced a mosaic of all shots together to create an overall model.
Three Dimensional Digital Database of 725 Archaeological Artifacts
Development
and implementation of a three-dimensional digital database of 725
archaeological artifacts to facilitate cultural resources curation
requirements at Fort Hood, Texas.
Three-dimensional scanning has the potential to alleviate a persistent problem in archaeology: the unavailability of artifacts to both researchers and the public. Artifacts that must be curated, stored, or repatriated can be recorded and used for digital comparative collections or educational material. Such data availability opens the door to better comparative analysis and public awareness. The project was successful in developing a three-dimensional digital database that improves the business process of curation so that research, Native American consultation efforts, and public education objectives are facilitated at Fort Hood.
Wilson County Bridge 3D Laser Scan and Seguin Creek 3D Visualization
GMI completed scan post-processing and integration, and basic solid modeling for these 3D visualization projects. Ten scans were done at the Seguin Creek site. Because the scans at Seguin Creek were done in tandem with professional surveying, the Seguin Creek model is completely georeferenced. Despite some vegetation removal, the preponderance of vegetation and debris makes solid modeling of this site challenging. However, by carefully decimating the data, an accurate and detailed contour map was generated.
Forty-eight scans were conducted of the Wilson County Bridge structure from a number of locations above, below, and on either side of the bridge. Two Cyrax units were used simultaneously at the site—one taking detail scans from a close range, and the other focusing on recording the overall structure. Four very close-range detail scans were done with a Minolta Vivid 900 at the bridge as well. These scans included two details of the Carnegie imprint on the steel beams, a load-bearing joint on the deck of the bridge, and a support articulation underneath the bridge. The project methodology was designed in order to thoroughly record the bridge structure such that all meaningful construction details would be identifiable. For example, model resolution was hoped to be of high enough quality to illustrate fasteners such as bolts. Recordation quality and completeness was intended to be great enough to serve as a basis for HAER Level I-type engineering drawings.