Optical inspection for quantification of decay on stone surfaces

Abstract

This paper examines a novel approach of corrosion damage analysis based on image processing for quantitative and qualitative evaluation of degradation effects on stone surfaces. This methodology can be applied in situ in association with a variety of nondestructive monitoring schemes, and on images acquired from several imaging modalities, capturing from micro-to macro-scale characteristics. Our analysis methodology was evaluated on three non-destructive monitoring techniques of cleaned and not cleaned stone surfaces, namely on digital camera, reflectography and fiber optic microscope images. Further to validating the potential of the various imaging modalities, the paper also assesses the corrosion rate and the efficiency of the recruited cleaning methods. The derived results are in accordance with chemical analyses revealing the deterioration patterns of the studied surfaces. r

Holistic approach of pre-existing flaws on the decay of two limestones

“…In case of the Noyant stone, the weathering by crystallizing gypsum was mainly restricted to the microporous matrix of the stone, while in case of the Lede stone, several foraminifera and shell fragments were preferentially recrystallized. In general, the underlying microstructure determines the weathering pattern of the stone.Different techniques have been used to characterize natural building stones and their weathering patterns ranging from optical inspection and optical microscopy (Bai et al, 2003;Kapsalas et al, 2007) to SEM, infrared and X-ray diffraction (Maravelaki-Kalaitzaki and Biscontin, 1999;Montana et al, 2008;Thomachot-Schneider et al, 2008;Thomachot and Jeannette, 2004). Recently, new techniques like high resolution X-ray computed tomography (HRXCT) are being addressed in the assessments of weathering of natural building materials (Bugani et al, 2008;Cnudde et al, 2004;De Graef et al, 2005;De Muynck et al, 2011;Rozenbaum, 2011).…”

Towards a more effective and reliable salt crystallization test for porous building materials: state of the art

“…6 Optical profilometer [using a white light (CLA) gauge] for monitoring of surface changes decay and monitor its evolution. Other authors use a combination of digital camera, reflectography and fiber optic microscope images [121]. Recently, more advanced techniques such as X-ray CT [23,122], and neutron tomography [123] have been successfully applied to study the development of damage in the bulk of the material.…”

Limpieza ideal y limpieza real en Patrimonio Arquitectónico

“…La necesidad cada vez mayor de evaluaciones in situ que reduzcan la toma de muestras, ha favorecido en los últimos años el desarrollo, y en algún caso la comercialización, de instrumental con el que obtener información sobre las transformaciones superficiales provocadas por la limpieza (Weinhold et al 2007), a la vez que se investigan metodologías y protocolos que permitan profundizar en las valoraciones (Papadakis, Loukaiti y Pouli 2010;Delegou et al 2008;Kapsalas et al, 2007;Moropoulou et al 2007). Existen también equipos portátiles con técnicas no destructivas o semidestructivas que permiten analizar, monitorizar y obtener datos precisos sobre el tratamiento (Blanco Domínguez 2010).…”