Browsing by Author "Gigilashvili, Davit"
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Item Does Higher Refractive Index Mean Higher Gloss?(The Eurographics Association, 2024) Gigilashvili, Davit; Diaz Estrada, David Norman; Haines, Eric; Garces, ElenaAccording to Fresnel equations, the amount of specular reflection at the dielectric surface depends on two factors: incident angle and the difference in refractive indices of inner and outer media. Therefore, it is often assumed that the higher the refractive index of the material, the glossier it looks. However, gloss perception is a complex process that, in addition to specular reflectance, depends on many other factors, such as object's translucency and shape. In this study, we conducted two psychophysical experiments to quantify the impact of refractive index on perceived gloss for objects with varying degrees of translucency and surface roughness. For some objects a monotonic positive relationship between refractive index and perceived gloss was observed, while for others the relationship was found to be non-monotonic. Afterward, we evaluated how the refractive index affects image cues to gloss and tried to explain psychophysical results by image statistics.Item Using Spatial Augmented Reality to Increase Perceived Translucency of Real 3D Objects(The Eurographics Association, 2023) Trumpy, Giorgio; Gigilashvili, Davit; Bucciero, Alberto; Fanini, Bruno; Graf, Holger; Pescarin, Sofia; Rizvic, SelmaTranslucency is an important optical and perceptual attribute that has a significant impact on the appearance of objects and materials. Expensive and time-consuming manufacturing process is required to produce a translucent replica of an opaque real object. The human visual system has a poor ability to understand optics, and it relies on intensity distribution in the image to distinguish translucent and opaque materials. In this work we demonstrate a novel method of using spatial augmented reality to increase perceived translucency of more optically opaque real 3D objects by projecting energy patterns onto them that mimic the energy distribution of optically translucent materials. We conducted a user study to verify that the result looks convincing, and it is impossible to tell the transmitted and projected light apart. This opens promising directions for effective alteration of material appearance using projection systems, which can be used to enhance understanding and appreciation of historical artifacts.