Digital image processing methods for the evaluation of optical anisotropy effects in tempered architectural glass using photoelastic measurements

Abstract In the present paper, optical anisotropy effects in architectural glass are evaluated using digital image processing. Hereby, thermally toughened panes were analyzed quantitatively a circular polariscope. Glass subjected to externally applied stresses or residual becomes birefringent. Polarized light on birefringent materials causes interference colors (iridescence), referred as anisotropies, which affect appearance of building envelopes. Thermally glass, such safety heat strengthened show these iridescences due induced stress differences. RGB-photoelastic full-field methods allow quantitative measurement since occurring related measured retardation values. By calibrating polariscope, images generated from non-directional isochromatic computer algorithms. The analysis and evaluation quality is great interest order detect sort out very low directly production process. Therefore, this paper acquired different then processing presented applied. It shown that general definition exclusion zones, e.g. near edges required prior evaluation. parallel, limitations application first-order statistical threshold presented. intend investigation extension texture based generation Grey Level Co-occurrence Matrices, where spatial arrangement values considered For first time, results textural features pane formats could be compared reference areas geometry factors. reduction original size, computation time algorithms remarkably speeded up, while remained same. Finally, knowledge gained investigations used determine uniform features, also includes pattern glass. Together with global criterion can now implemented commercial systems for control tempered