Incidence of environmental factors on travertine façade of heritage buildings in the historic center of Cuenca-Ecuador. A test scenario through Digital Imagen Processing

Abstract

The problem of architectural heritage conservation in a consolidated historic urban context is of worldwide relevance. In Ecuador, and specifically in Cuenca, there are no specific approaches to evaluate the environmental impact on the heritage deterioration, therefore, an alternative diagnostic of travertine facades is proposed to define the levels of deterioration based on climatic factors through a case study. Two research stages are developed; 1) preliminary diagnosis of the architectural, environmental and anthropic components, using architectural cards and Leopold’s Multivariable Matrix; and 2) quasi-experimental analysis with a mixed approach (quantitative and qualitative) based on real-time data collection of potential environmental variables to generate deterioration, which focuses on image processing. This technique is gaining momentum because it offers the possibility of studying the characteristics of surfaces through a non-invasive procedure. This paper describes the application of the Normalized Difference Vegetation Index (NVDI) algorithm applied to RGB images known as False-NVDI in order to obtain the deterioration caused by the incidence of environmental factors on the travertine facades. In particular, images of two buildings belonging to the Historic Center of the City of Cuenca were used. The results indicate that this technique has a great potential to determine three levels of deterioration; good, fair and bad. At the same time, it is confirmed that the proposed methodology is an effective and low-cost tool with high potential for short-term application in previous studies and more extensive research prior to intervention.