本期为大家推荐的内容为论文《
Measurement of urban vitality with time-lapsed street-view images and object-detection for scalable assessment of pedestrian-sidewalk dynamics
》（
利用延时街景图像与目标检测测量城市活力——面向人行道行人动态的可扩展评估方法
），发表在
ISPRS Journal of Photogrammetry and Remote Sensing
期刊，欢迎大家学习与交流。
高密度混合用途环境与步行化原则对全球城市规划实践具有深远影响。这些原则倡导的核心目标是创造"城市活力"，即通过全天候持续利用街道人行道基础设施，提升城市社区的安全性、经济可行性和吸引力。理论假设认为，活力源于邻近区域的混合主导功能、短街区形态、建筑与人口密度，以及周边建筑的年代与状况多样性。为验证这一假设，本研究采用加纳阿克拉市145个代表性点位获取的210万张昼夜延时图像构建新型数据集，并基于图像中行人流量随时间变化的变异系数（通过目标检测技术识别人群计数）开发了各点位的城市活力量化指标。同时，利用多城市可获取数据构建"多样性生成因子"指标，包括混合用途强度、建筑密度、街区密度、人口密度及建筑年代多样性，并通过双变量与多变量回归分析检验这些因子与活力指标的关联性。研究发现，在步行五分钟范围内存在两种及以上不同类型的便利设施、建筑密度（涵盖不同年代与状态）以及短街区形态，与更均衡的全天行人流量显著相关。然而，分析也提示高密度混合用途社区可能伴随潜在负面影响，例如更持续的全天道路交通流量。本方法框架具有可扩展性，可适配不同图像数据模式，为城市动态研究提供灵活工具。
题目：
Measurement of urban vitality with time-lapsed street-view images and object-detection for scalable assessment of pedestrian-sidewalk dynamics
（
利用延时街景图像与目标检测测量城市活力——面向人行道行人动态的可扩展评估方法
）
作者：
Ricky Nathvani
*
, Alicia Cavanaugh, Esra Suel, Honor Bixby, Sierra N. Clark, Antje Barbara Metzler, James Nimo, Josephine Bedford Moses, Solomon Baah, Raphael E. Arku, Brian E. Robinson, Jill Baumgartner, James E Bennett, Abeer M. Arif, Ying Long, Samuel Agyei-Mensah, Majid Ezzati
发表刊物：
ISPRS Journal of Photogrammetry and Remote Sensing
DOI：
https://doi.org/10.1016/j.isprsjprs.2025.01.038
Principles of dense, mixed-use environments and pedestrianisation are influential in urban planning practice worldwide. A key outcome espoused by these principles is generating “urban vitality”, the continuous use of street sidewalk infrastructure throughout the day, to promote safety, economic viability and attractiveness of city neighbourhoods. Vitality is hypothesised to arise from a nearby mixture of primary uses, short blocks, density of buildings and population and a diversity in the age and condition of surrounding buildings. To investigate this claim, we use a novel dataset of 2.1 million time-lapsed day and night images at 145 representative locations throughout the city of Accra, Ghana. We developed a measure of urban vitality for each location based on the coefficient of variation in pedestrian volume over time in our images, obtained from counts of people identified using object detection. We also construct measures of “generators of diversity”: mixed-use intensity, building, block and population density, as well as diversity in the age of buildings, using data that are available across multiple cities and perform bivariate and multivariate regressions of our urban vitality measure against variables representing generators of diversity to test the latter’s association with vitality. We find that two or more unique kinds of amenities accessible within a five-minute walk from a given location, as well as the density of buildings (of varying ages and conditions) and short blocks, are associated with more even footfall throughout the day. Our analysis also indicates some potential negative trade-offs from dense and mixed-use neighbourhoods, such as being associated with more continuous road traffic throughout the day. Our methodological approach is scalable and adaptable to different modes of image data capture and can be widely adopted in other cities worldwide.
