I-Corps: Videogrammetric Roof Surveying System for Digital Fabrication of Sheet Metal Roof Panels

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

This proposal investigates a structured hypothesis / validation approach to develop a disposition plan for a video-based roof-surveying technology. This technology is capable of extracting as-built dimensions of a roof structure using a less expensive, faster, safer, and simpler method compared to the existing techniques, while being able to satisfy the required level of accuracy. If successful, it will be the world's first video-based roof surveying method that has the mentioned features at the same time. When using it, a roofing contractor will simply collect stereo videos from a roof using a camera set and send it to a server via the 3G/4G capability of a Tablet PC. At this server, different forms of visual features are detected and matched across different views of the scene; this allows chaining the available information in the videos and extracting the corresponding 3D information. A 3D wire diagram of the target roof is finally generated which includes as-built dimensions of each plane. In the sheet metal roofing industry, the output of this technology can be imported to an on-site roll forming machine to roll form and cut sheet metal coil into precise, ready-to-install roof panels. This project has the potential to bring the roofing trade up to the modern standards of CAD/CAM used in many other industries and has the potential to address the inherent deficiencies of the existing methods for roof surveying. Compared to tape measuring, the use of this technology will significantly reduce measuring costs and also eliminate the exposure of employees to fall hazards, thereby decreasing the very high number of occupational injuries and fall deaths which occur in the roofing industry (7 percent of private construction fatalities in 2009). The simplicity of the method will remove the need for trained surveyors who are required for surveying with a total station. The video-based roof surveying technology could be used by virtually any roofing contractors worldwide. Beyond the initial target industry (i.e., roofing), it could be adapted to many of the other building trades where as-built documentation is required to build components. It has also the potential to be used in any indoor and outdoor application that requires tape measuring such as commercial build-outs, kitchen and bathroom cabinets or countertops, flooring, window installation, and siding. This, in turn, will result in time and cost savings, which could improve the efficiency of the construction industry.