Refining the potential visual exposure index for the assessment of residential visual privacy: a three-dimensional study

Abstract

Residential visual privacy is an important issue in modern society. This paper proposes an improved Potential Visual Exposure Index (I-PVEI) to evaluate the privacy risks of visual exposure along building facades in a dense residential environment. Compared with the PVEI indicator, the proposed method introduces the observer’s view direction based on visual perception and applies a weighting scheme to construct the I-PVEI. To validate the I-PVEI, a case study with a neighborhood located at the center of Kowloon, Hong Kong, was evaluated. The results demonstrate: (1) Potential observers from building and pedestrian levels had different impacts on the neighborhood, resulting in different I-PVEI distribution patterns on the building facades; (2) Although significant changes of I-PVEI value could be found across building facades, I-PVEI values always presented a uniform change trend on the same façade; (3) The quantitative indicator can perceive subtle privacy risks of openings located at the corner of the building, which was overlooked by the PVEI. The results indicate that the proposed I-PVEI can be an optional indicator for the assessment of residential visual privacy in urban planning and building design.