Robust In-Situ Measurements of Haze in Glass Facades

Abstract

Haze in transparent glass façades is a subtle optical defect that becomes visible only under specific environmental conditions, yet it can significantly affect the visual quality of high performance glazing. Detecting low haze levels during production remains challenging, as visual inspection is unreliable and existing haze meters are primarily intended for laboratory testing of small plastic samples. This paper presents a refined, non destructive methodology for the in situ characterisation of low haze levels in installed glass façades, building upon previous work by the authors. The approach is based on luminance imaging of the characteristic halo produced when hazy glass is illuminated by a collimated light source. A new post-processing framework is introduced, in which radial and cumulative luminance profiles derived from high dynamic range images are used to compute a drop off rate indicator describing light dispersion. The method is validated using reference samples with known haze values and subsequently applied in a unique on-site measurement campaign on a luxury boat with double curved glass façades. Results demonstrate the feasibility, repeatability and limitations of the approach under real installation conditions.