Perception of urban street visual color environment based on the CEP-KASS framework

The colors of urban streets play a vital role in shaping the city's image and influencing people's emotional perceptions. However, the relationship between street color environments and residents' perceptions has rarely been explored in depth, and existing studies predominantly adopt qualitative approaches. To accurately and effectively assess the connection and impact between street landscape colors and residents' emotional perceptions, this paper introduces a quantitative research framework based on multi-source data: the Color Emotion Perception framework with K-Means, SegNet, and SVM (CEP-KASS). This framework innovatively integrates residents' perceptions with urban color characteristics, offering a new perspective and direction for urban color planning. This study focuses on the central districts of Tianjin, employing machine learning models to predict human perception of Baidu Street View Images (BSVI) and to extract color characteristics from these images. An analysis is then conducted on the relationship between street landscape colors and human emotional perceptions. The findings indicate that, in terms of color perception, the prevalence of blue and green is positively correlated with emotions of prosperity and vitality, while the prevalence of red and yellow is negatively correlated with feelings of safety. Regarding color attributes, bright colors lead to higher boredom perception scores in urban street spaces, while excessively low brightness reduces the attractiveness of these areas to residents. Brightness is inversely related to vitality perception scores, and modulating brightness inversely can enhance the vitality perception in urban outdoor spaces. The main contribution of this study lies in its analysis of the relationship between street colors and human perception from the perspective of color psychology. Additionally, the CEP-KASS framework facilitates comprehensive measurement and analysis of color and perception, which can be extended to research in other cities. The research findings provide valuable insights for planners, allowing them to consider the impact of color changes in decision-making to enhance residents' spatial perception and emotional experience.