Assessment of visual landscape quality of urban green spaces using image-based metrics derived from perceived sensory dimensions

Urban green spaces (UGS) have been extensively studied for their psychological benefits to people. However, accurately assessing the quality of UGS, which is closely linked to human perception, remains challenging due to the complexity of this attribute. To address this gap, this study proposed a novel approach that uses comprehensive image-based metrics to evaluate multiple aspects of visual landscape quality (VLQ). These metrics were developed based on a theoretical framework of perceived sensory dimensions (PSD). We presented the meanings and calculation methods of metrics based on panoramic images. Additionally, we conducted an online survey to demonstrate the significant correlation between these metrics and the subjective perception of PSD. This study also proposed a new spatial mapping method to represent VLQ using these metrics, illustrated through a case study of the Singapore Botanic Gardens (SBG). We used analysis of variance to compare the distinctions between metrics naturalness, wildness, and GVI by selecting a few green spaces within the SBG. The approaches provide an innovative way to evaluate UGS visual quality using photographic imagery data, contributing to a more comprehensive understanding of the visual quality assessment of UGS.