Building façade color plays a key role in shaping urban image, enhancing urban vitality, and optimizing citizens’ living experience. Moreover, colors can influence people’s perception of space, but the multiple interrelationships between color elements and users’ color evaluation and visual perception have not yet been thoroughly studied. In order to explore the relationships between color elements and visual perception and subjective comfort, this study discusses the matching relationship between color and the comfort of a residential building façade from three levels of color hue, lightness, and saturation by combining eye movement technology and a subjective evaluation. Taking Anshan San Village in Shanghai as the research object, the relationship model between color elements, visual perception, and subjective comfort is established through correlation analysis, linear regression, and multifactor regression analysis, and the correlation between single elements and multiple elements is explored from multi-dimensional perspectives. It aims to assess the operability of eye movement data as a measure of the visual comfort with the residential building façade color through multiple indicators and to explore and establish a new correlation assessment framework between the three attributes of façade color and users’ visual comfort. The results show that (1) highly saturated façade colors significantly increase cognitive load and decrease color evaluation. (2) Brightness has a non-linear relationship with visual perception and subjective evaluation, either too high or too low a brightness value will cause visual fatigue and thus reduce the color evaluation, and when the brightness is maintained at 40–80%, there will be a better color experience. (3) Warm tones such as red, orange, and yellow can strengthen the color perception to enhance the color evaluation of the façade; among cold tones, cyan and purple can also strengthen the visual perception of the color of the façade to enhance the color evaluation. After validation, the proposed new color comfort assessment method is feasible and comprehensive, and we hope it can provide a reference for the planning of old residential buildings and communities in the future.

Architectural colors significantly influence urban culture, city imagery, regional vitality, and residential experiences. Previous studies have demonstrated that appropriate architectural colors can enhance urban vitality, but research on multicolored buildings remains limited. This study examines the relationship between hue, color variations, and visual quality by cross-verifying eye-tracking physiological indicators with subjective assessments. Using digital models of old residential buildings in Shanghai’s Yangpu District, different color combinations were applied to explore real-world architectural color impacts. Results showed that blue and green combinations reduced visual pressure and created a calming space, while purple combinations were rated highly in both visual perception and subjective evaluations. Brightness differences notably influenced visual quality more than hue differences. However, larger hue variations, when paired with suitable brightness and saturation contrasts, also achieved better visual evaluations. This study fills a research gap by providing mathematical support for color combinations in architectural design, improving visual comfort and enhancing urban vitality.

Street vitality is an important indicator of urban attractiveness and sustainable development, and it has become a central topic in contemporary urban planning and research. Using the PRISMA methodology, this review systematically examines four major technologies including machine learning (ML), space syntax, GPS, and sensors, together with six categories of data that are commonly used in street vitality studies. The analysis traces the methodological development of these approaches and identifies application trends across both macro and micro spatial scales. ML has become the leading technology in this field, showing strong performance in dynamic modeling, pattern recognition, and the integration of multiple data sources. GPS provides high temporal accuracy for tracking mobility and identifying spatiotemporal dynamics. UAVs and sensor networks make it possible to observe environmental and behavioral responses in real time. When combined, these technologies support four main research themes: the built environment and vitality, pedestrian mobility and urban dynamics, spatial and visual characterization, and social interaction. Other complementary data sources, including social media, online maps, surveys, and government statistics, expand analytical coverage and improve contextual interpretation across different spatial and cultural settings. The review emphasizes the need to connect advanced technologies and diverse data sources with broader concerns of governance, ethics, and civic participation, while maintaining a focus on methodological and data-based synthesis. By clarifying the technological pathways and data foundations of street vitality research, this study provides a structured reference for researchers, urban designers, and policymakers who aim to develop evidence-based and socially responsive frameworks for urban space evaluation and planning.

Historic districts, as important spatial units that carry urban cultural memory and everyday social life, play a crucial role in shaping residents’ spatial identity, emotional attachment, and perceptual experience. Although quantitative research on built environments and perception has advanced considerably in recent years, the mechanisms through which perception is formed in historic districts, particularly the nonlinear threshold effects and perceptual trade-off patterns that arise under conditions of high-density and mixed land use, remain insufficiently examined. To address this gap, this study develops an analytical framework that integrates spatial attributes with multidimensional subjective perceptions. Focusing on six historic districts in central Shanghai, the study combines micro-scale environmental indicators extracted from street-view imagery, POI data, and public perceptual evaluations and employs an XGBoost model to identify the nonlinear response patterns, threshold effects, and perceptual trade-offs across seven perceptual dimensions. The results show that natural elements such as visual greenery and sky openness generate significant threshold-based enhancement effects, and once reaching a certain level of visibility, they substantially increase positive perceptions including beauty, safety, and cleanliness. By contrast, commercial and traffic-related facilities exhibit dual and competing perceptual influences. Moderate densities enhance liveliness, whereas high concentrations tend to induce perceptual fatigue and intensify negative emotional responses. Overall, perceptual quality in historic districts does not arise from linear accumulation but is shaped by dynamic perceptual trade-offs among natural features, functional elements, and cultural symbolism. Overall, the study reveals the coupling mechanism between spatial renewal and perceptual experience amid the pressures of urban modernization. It also demonstrates that increasing visible greenery (e.g., planting street trees, incorporating micro-green spaces, improving façade greening), enhancing street openness (e.g., optimizing view corridors, reducing visual obstruction, implementing moderate setback adjustments), guiding a moderate mix and spatial distribution of commercial and service functions, and strengthening the perceptibility of cultural landscape elements (e.g., façade restoration, streetscape coordination, and improved signage systems) are concrete and effective planning and design actions for improving landscape quality and enhancing the experiential quality of historic districts.