Aerial photogrammetry for monitoring construction pathologies using pixel-based fuzzy logic, case study: Igrejinha da Pampulha

This article presents part of the master’s dissertation submitted to the Graduate Program in Built Environment and Sustainable Heritage (PPGACPS) at the School of Architecture of the Federal University of Minas Gerais (UFMG), Brazil. The article discusses the state of the art in scientific documentation of architectural heritage and the Heritage Building Information Modelling (HBIM) methodology applied to damage monitoring. The presented study aims to investigate an approach for using RPA (Remotely Piloted Aircraft) as a tool for scientific documentation, in mapping, monitoring, and conservation diagnosis protocols for architectural cultural heritage. The case study involves monitoring a crack located on the roof of the Church of São Francisco de Assis, better known as “Igrejinha da Pampulha,” an iconic work of modern Brazilian architecture, located in Belo Horizonte, MG. The method involved photogrammetry techniques performed with RPA, analysis of digital images through binarization techniques and pixel recognition in Raster images. It concludes that the methodology can be effective for damage monitoring on larger scales. In the case study, the Ground Sampling Distance (GSD) ratio generated a 2 × 2 cm pixel, resulting in an error of two square centimeters in crack monitoring through matrix data analysis, which can be altered with a higher resolution camera and a lower flight height. The main result is a methodological proposal for monitoring cracks in the dome of the studied building. The main conclusion is that the methodology is effective, especially when applied to large-scale objects, such as dam monitoring. It is recommended that in future inspections, if the same equipment is used, the flight should be conducted at a shorter distance from the object of study. The study demonstrates the potential of digital surveying performed by RPA as well as the HBIM methodology as a form of documentation, extroversion, and management of architectural cultural heritage.