Review of digital image analysis of petrographic thin sections in conservation research

This paper reviews published conservation research that utilizes digital image analysis of petrographic thin sections. Examples involve quantifying quartz microcrack patterns to analyze stone deterioration, conducting porosimetric studies of stone, examining grain-size distribution and grain shape in stone, comprehensively evaluating deterioration mechanisms of stone, studying conservation treatments of stone, characterizing cementitious materials, analyzing ceramic materials, and measuring layer thickness on a variety of materials. Background issues that must be understood before undertaking or evaluating image analysis include experimental design and statistical validity, calibration, image quality, and image enhancement (preprocessing of images). Early work often required in-house computer programs; recent studies make use of new comprehensive image analysis packages. With the emergence of these packages that provide fast preprocessing and measurement of a wide range parameters, we can expect increasing use of image analysis of petrographic thin sections as an analytical tool in the future.