Preserving a Historic Sugar Mill Using the FARO Laser Scanner

Documenting the past with today's leading portable coordinate metrology systems

Published: Thursday, February 10, 2011 - 12:31

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rchaeologists and researchers from the University of South Florida’s Alliance for Integrated Spatial Technologies (AIST) are working with state officials to help protect, preserve, and restore threatened historic sugar mill ruins in Florida. These structures are associated with the 18th and 19th century Florida sugar industry, and are made from coquina and/or lime rock and mortars, each of which face special issues of deterioration from weathering of their exposed surfaces.

Previous restoration efforts used materials like Portland cement to repair coquina and limestone structures, methods now known to cause structural concerns such as cracking and fissuring of surface features. Developing new methods for examination, documentation, and analysis of structural integrity, and pinpointing areas for restoration and conservation, is a statewide and national need for heritage management.

The objectives of this multi-year restoration project include the survey, documentation, and analysis of the early history of the Florida sugar industry from its inception in the 1760s and its development through the late 1800s. The purpose is to preserve and promote the cultural, historic, and architectural heritage engendered by the state’s sugar mills. The larger project is designed to maximize participation of graduate students in history, architecture, archaeology, and anthropology at the University of South Florida. The results will provide local, regional, and state planners and managers of Florida’s cultural heritage a variety of new data that can be used to conserve, restore, and protect these non-renewable resources.

One sugar mill in particular, Dummett Mill located in Ormond Beach, Florida, is an example to why preservation measures need to be planned quickly and accurately. After a brief spatial survey was documented, a structural collapse of the mill’s north wall was discovered by the team of researchers. AIST and park officials decided to salvage the wall before further damage could occur, but this project would require accurate 3-D CAD documentation for analysis before any physical restoration could begin.

AIST researchers Travis Doering, Ph.D., and Lori Collins, Ph.D., used advanced laser scanning techniques to completely document these structures in three dimensions, and worked with restoration specialists, land resource managers, and state and federal agencies to develop new ways of protecting these heritage sites. The FARO laser scanner was used to gather data consisting of millions of x, y, and z coordinates in a point cloud, all within a +/– 2-mm accuracy. These data sets, taken post-collapse, focused on the southern face of the north wall area where the collapse had occurred. The survey was performed at the same time as an on-site reconnaissance in conjunction with participating structural and architectural engineers and state officials to determine a plan of action for stabilization.

FARO SCENE and Kubit Point Cloud software were utilized with the laser scan data collected from the two 3-D surveys at Dummett Mill conducted both before and after the collapse in 2009. SCENE filters and registers the scans together, and Kubit Point Cloud allows for 3-D point clouds to be utilized within the AutoCAD environment to produce 2-D drawings. This interface proved useful in allowing architectural partners to receive data for analysis in 2-D construction formats, and permitted a seamless processing and analysis tool for modeling. The 3-D and 2-D models and drawings were then analyzed to examine areas of structural concern in an effort to better understand the complex historic ruin. This research enhances awareness and ongoing forensic analysis of the historic changes made to the structure, previous areas, and types of restoration, as well as areas that may present future collapse and stabilization risks. These data are also useful not only for their as-built information, but for developing models of what the site may have looked like historically, based on extant remains that are now digitally documented. These formats have useful functions for interpretive development and long-term management planning for the site.

Bringing together data sets from separate laser scans and documentation surveys of historic sugar mill ruins in Florida, researchers at USF are learning more about the social dynamics and infrastructure development at these plantation sites, and are learning improved ways of documenting and analyzing these complex ruin sites to better protect and restore features of state and national significance. Using a suite of spatial tools, including the FARO laser scanner and post-processing software applications, AIST at USF is working with state and federal land managers on new ways of protecting and preserving the past. Landscape examination and comparison of these sites through time will include the examination of slavery aspects and social dynamics that were part of the beginnings of the sugar industry. These documentation projects are providing valuable data and information for land managers. They are also affording students at USF technological skills and learning opportunities, as well as fostering relationships and internship opportunities with state and federal partners.

The workflow for documentation, including laser scanning and post-processing with 3-D models, 2-D line drawings, and as-builts, demonstrate new possibilities for heritage management. New technologies used in laser scanning, such as the FARO laser scanner used in this case study, are offering fast and economical ways of capturing data more completely and accurately than possible from traditional methods. The integration of color imagery with the laser scanner allows for better visualizations and greatly benefits the restoration and conservation efforts by documenting textures and surfaces more realistically. The seamless workflow from SCENE point cloud processing to CAD work via new and innovative software such as Kubit Point Cloud provides the ability to draw directly from the real data, eliminating the need for less accurate and more time-consuming tape measurements, or subjective drawing from photographs. The exceptional detail captured in these laser scans of Florida historic sugar mill ruins will promote the continued use of these data sets into the future for other types of analysis or research questions in heritage management. The ability for managers and restoration specialists to more completely visualize and study these mill ruins, remote from the site, will improve conservation strategies and maintenance planning that will lead to better and more effective preservation and restoration.

About The Author

FARO

FARO develops and markets computer-aided coordinate measurement and imaging devices and software. FARO’s portable equipment permits high-precision 3-D measurement, imaging, and comparison of parts and compound structures within production and quality assurance processes. The devices are used for inspecting components and assemblies, production planning, 3-D documentation, as well as for investigation and reconstruction of accident sites or crime scenes, and to generate digital scans of historic sites. Principal products include the FaroArm, the FARO Laser Tracker ION, FARO Laser ScanArm, FARO Laser Scanner, FARO Gage, and the CAM2 family of advanced CAD-based measurement and reporting software.