This short workshop will demonstrate the role of 3D Scanning and Photogrammetry in recording the physical configuration of historic buildings. Mario Santana Quintero will show how to operate the equipment and demonstrate the potentials of using this technology in addition to identifying the constraints.
This workshop is only open to current GSAPP students sign up here to receive trial software and tutorials prior to attending the workshop:
According to Historic England, 3D Scanning allows “to survey building façades and interiors, resulting in line drawings (with supporting data) and surface models” (English heritage, 2007, pp.7).
Furthermore, this type of scanning device acquires measurements by using a “two-way travel time of a pulse of laser energy to calculate a range” and “This type of scanner can be expected to collect many tens of thousands of points every minute by deflecting this laser pulse across the surface of an object, using a rotating mirror or prism“ (English Heritage, pp. 8). The resulting data is millions of points in 3d space, called a Point Cloud.
Also, Böhler and Marbs generically describe a laser scanner as a “device that collects 3D co-ordinates of a given region of an object’s surface automatically and in a systematic pattern at a high rate (hundreds or thousands of points per second) achieving the results (ie three-dimensional co-ordinates) in (near) real time.” (Böhler & Marbs, 2002) Several sets of point cloud data can be merged together from separate scanning exercises if controlled survey points are established. From the combined point cloud data, detailed three-dimensional models can be generated.
Photogrammetry can be defined as “the art, science, and technology of obtaining reliable information about physical objects and the environment through the processes of recording, measuring, and interpreting photographic images.” (Wolf, Dewitt, & Wilkinson, 2014). This technique can obtain measurements of objects, buildings, sites or earth surfaces. When images are clear and captured at a high resolution it can be a very accurate technique based on the assumption that photographic images are in perspective as well as generated from a centrally projected system and, therefore, follows geometric and mathematical principles.
For the purpose of this workshop, “multi-image photogrammetry or structure from motion” (McCarthy, 2014, pp. 175) will be used, which is an approach product of recent developments in computer vision that allows us to obtain 3D scenes from 2D images using highly automated workflows. This was carried out by capturing a sequence of overlapping and oblique images taken from a scene (or subject) at the same distance. Recent algorithms allow matching features between pairs of photographs in sequences, which along with the information contained in the images (adequate camera motion, overlap and structure scene) uses the camera parameters to calibrate the images. Subsequently, with this information a depth map is created with each pixel contained in the image producing a 3D dense point cloud and/or surface model. The results can be mesh models of important rooms and spaces.
Mario Santana Quintero is an assistant professor on Architectural Conservation and Sustainability at department of Civil and Environmental Engineering Carleton University. He is also the Director of the NSERC Create program “Engineering Students Supporting Heritage and Sustainability (HERITAGEENGINEERING)” based at the Carleton immersive Media Studio Lab (CIMS). He has an architectural degree, holding a master in conservation of historic buildings and towns and a PhD in Engineering from the R. Lemaire International Centre for Conservation (University of Leuven, Belgium). He is also a guest professor at the Raymond Lemaire International Centre for Conservation (University of Leuven).
These past years he has been teaching at the Universidad Central de Venezuela, Universidad de Guadalajara (Mexico) and Universidad de Cuenca (Ecuador). In the past, he was a Professor at the University College St Lieven and lecturer at the University of Aachen RWTH and the Historic Preservation Programme at the University of Pennsylvania between 2006 and 2011. Along with his academic activities, he serves as ICOMOS Board member and he is the past president of the ICOMOS Scientific Committee on Heritage Documentation (CIPA). Furthermore, he has collaborated in several international projects in the field of heritage documentation for UNESCO, The Getty Conservation Institute, ICCROM, World Monuments Fund, UNDP, Welfare Association, and the Abu Dhabi Authority for Culture and Heritage.