Evaluation of safety perception of elderly people based on urban street view and deep learning:Taking the central city of Shenyang as an example
In recent years,under the background of macro-policy emphasizing on human-centredness,urban design practice and control have gradually transformed from"growth priority"to"quality enhancement",and the increasing spatial quality of the public has given rise to the study of urban spatial quality from the humanistic perspective.Urban regeneration and reconstruction should not only see"things"but also"people",and the perception measurement of human scale has become an important basis for urban regeneration decision-making.The health and safety of the elderly in the built environment has always been a common concern of urban planning,urban management,environmental psychology and other disciplines.Safe and comfortable urban space that meets the behavioral characteristics of the elderly population is the basis for improving urban quality.In this context,researchers and designers need to answer the key question of"how the elderly perceive and use space under the human scale,and how and to what extent the physical space affects the perception and behavior of the elderly".With a series of new technologies,it has become possible to measure the perceived safety level of the aging population from a human-centred perspective in a highly efficient and large-scale manner,and then to achieve a fine-grained planning and design guidance and control.Therefore,the establishment of a"perception-evaluation-optimization"analysis framework of urban space for the aging population is helpful for the realization of fine-tuned planning and design.In this study,the central city of Shenyang,a heavily aging megacity,is taken as the research object,and deep learning is used to semantically segment the elements of the urban streetscape;a random forest model of the safety perception of the aging population with human-machine confrontation is established,and the streetscape in the central city of Shenyang is evaluated.In addition,the study also used Getis-Ord General G,augmented regression tree(BRT)modeling,and other methods to explore the relationship between the safety perception of the aging population and the built environment in urban space.The results show that,firstly,the level of safety perception of the elderly in Shenyang city shows significant spatial heterogeneity,the overall trend is high inside and outside,and the urban ring road shows a more obvious spatial progressive relationship;secondly,the study based on the analysis of spatial autocorrelation model to obtain the characteristics of the spatial clustering of safety perception,and analyze the probability of its relationship with the distribution of the nature of the different land use;the relationship of high clustering of the perception of safety(high:perception of safety)area with commercial land,residential land The relationship between the high clustering of security perception(high:security perception)areas and commercial land,residential land,public service facilities land is more obvious;the relationship between the low clustering(high:security perception)areas and industrial land,logistics and warehousing land is more obvious;thirdly,the trend of spatial distribution of the level of security perception in the neighborhoods of different land use types is similar to the trend of the overall level of the city,but there are some differences;residential land use is not obvious in the clustering of the city boundary between the new and old urban areas,and the hot spot clustering area extends northward in addition to the old urban area;the hotspot clustering area of commercial land is distributed in two lines in the north and south,with a high degree of overlap between the main metro lines of the city and the nodes of the commercial circle;public service facilities due to the number of parcels of land its dispersion,the cold hotspot clustering is not significant;fourthly,the study analyses,based on the BRT model,the level of the contribution of the elements of the streetscape with the level of security perception in the model of the human-computer confrontation and the marginal effect buildings(interface),sky(visibility),paving and walls,which shape the basic form and enclosure relationships of urban space.This study takes human-scale urban spatial data as a blueprint,and relies on new technologies and large models to carry out fine-grained measurement and analysis of large-scale perception for the aging population.Through data analysis,urban problems are revealed,and problem-oriented urban analysis is efficiently,rapidly and scientifically realized,which helps the science of decision-making.The limitation of the study is that the volunteers of the human-computer confrontation model for the aging population in this paper come from a relatively single source,and individual differences such as educational background are not taken into account,so we expect that the accuracy of the urban perception evaluation model will be revised in the future.
deep learningbuilt environmentsafety perceptionage-friendlyurban street view
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