Assessing visual perception in heritage sites with visual acuity : case study of the cathedral of St. John the Theologian in Nicosia, Cyprus

A challenging aspect of visibility studies is visual acuity, which concerns the clarity of vision within a given space in relation to variables such as spatial geometry, lighting conditions, the physical properties of the viewed object, or the familiarity of viewers with the target. Our research proposes a novel approach to visibility studies, based on visual acuity and its related pipeline, which integrates qualitative and quantitative aspects such as the cultural background of viewers, the illumination values of space, contrast, and size of objects of interest as well as their meaning and context. The proposed pipeline relies on 3D documentation of the investigated space, light measurements, research in optics, trigonometry calculations, and 3D GIS set against images and architectural space. The method's effectiveness is demonstrated in the study of the iconography of the Cathedral of St. John the Theologian in Nicosia, Cyprus, the work hypothesis being that the church's spatial organization, choice of scenes, and level of detail were carefully planned to establish visual narratives with strong political and religious connotations and to overall dictate the ways the building was accessed and experienced. The method can be broadly applied for visibility analyses in a variety of case-studies in closed spaces