Visual impact assessment of coloured Building-integrated photovoltaics on retrofitted building facades using saliency mapping

Abstract

Building-integrated photovoltaics (BIPV) is seen as a promising architectural application of PV technology on building envelopes for generating on-site renewable energy. In contrast to the traditional negative notion towards the visual impact of BIPV, “aesthetic BIPV” may even enhance the integration quality and produce a positive visual impact. Therefore, this research aims to objectively quantify the visual impact of BIPV in the built environment and clarifies its quality at the same time. The objective VIA approach is developed based on saliency mapping, a computer vision technique predicting human visual attention. As a case study, the proposed methodology is implemented to evaluate the perceived visual impact of a retrofitted coloured BIPV on four selected building frontages along Orchard Road in Singapore. Subjective surveys are implemented to validate the objective results, in which ratings of the visual impact of BIPV are collected based on the comparative street views with and without BIPV applications. Through validation, the proposed objective VIA methodology was determined as “qualified” for predicting the visual impact of BIPV. The proposed method can be applied as a planning or building design tool for urban planners and architects to objectively predict the visual impact of BIPV at the preliminary design stage.