The perceived quality of street lighting influences pedestrians’ perceptions of safety and visual comfort, as well as outdoors activities at night. This study explores the association between street lighting attributes, such as illuminance and wavelength, and pedestrians’ feeling of safety (FoS) and perceived lighting quality (PLQ) in eight residential districts in Dalian, China. To achieve this goal, we combine remote sensing technology with ground investigation. The ground research includes physical measurements of lighting attributes, such as intensity, color temperature, and glare, as well as survey evaluations of pedestrians’ perceptions of safety and visual comfort. We also analyze the influence of several environmental factors, such as traffic volumes and vegetation, while accounting for personal characteristics of the observers, such as gender and age. Findings from the remote sensing reveal that Dalian’s residential districts differ substantially by their nighttime light emissions, with high concentration of strong red band (i.e., long wavelength) emissions occurring in Zhongshan and Jinzhou, and strong blue band (i.e., short wavelength) emissions found in central Zhongshan. Results from the ground surveys further indicate that a satisfactory level of FoS reaches at the illumination levels of 5–17 lx, and that people feel safer if nighttime light is warm and uniform. From a multiple regression analysis, it is also found that illuminance and uniformity are the main factors affecting PLQ under conditions of low or high illuminance, while glare and color temperature play a more significant role under high illuminance. In addition, a satisfactory level of PLQ is found at illuminance levels of 25–35 lx and light color temperature of 4000 K–5500 K.

Light pollution has a serious impact on astronomical observations and ecological balance. So far, most scholars have carried out field measurements of urban sky glow luminance using satellite data. However, measurement of the light environment of an entire city is insufficient. This paper presents measurements of the sky within the city of Dalian and examines the changes in the distribution of luminance and colour temperature of the sky. It was found that over the transition from day to night the colour temperature of the sky decreases by approximately 2000 K–3000 K and the light spectrum transforms from a relatively uniform distribution to one with an obvious peak. Additionally, the zenith luminance is up to 0.01 cd/m², more than 50 times the standard dark sky luminance. Dalian experiences serious light pollution.

The International Space Station (ISS) offers a unique view from space that provides nighttime light (NTL) images of many parts of the globe. Compared with other NTL remote sensing data, ISS NTL multispectral images taken by astronauts with commercial digital single-lens reflex (DSLR) cameras have the characteristics of free access, high spatial resolution, abundant data and no light saturation, so it plays a unique advantage in the research of small-scale urban planning, optimization of lighting resource allocation and blue light pollution. In order to improve the radiation consistency of ISS NTL images, a relative radiation normalization method of ISS NTL images is proposed in this paper. Pseudo invariant features (PIF) were identified in the cloud-free Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) time series NTL remote sensing annual composite product, and then they were used to derive the relative radiation normalization model of ISS NTL images. The results show that the radiation brightness of ISS NTL images in different regions is normalized to the same gray level with that of DMSP/OLS NTL remote sensing images in the same year, which improves the radiation brightness comparability between different regions of ISS NTL images. This method is universally applicable to all ISS NTL images, which is beneficial to the NTL comparability of ISS NTL image in the regional horizontal and temporal vertical.

The urban canopy refers to the spatial area at the average height range of urban structures. The light environment of the urban canopy not only influences the ecological conditions of the canopy layer region but also serves as an indicator of the upward light influx of artificial nighttime light in the urban environment. Previous research on urban nighttime light environment mainly focused on the urban surface layer and urban night sky layer, lacking attention to the urban canopy layer. This study observes the urban canopy layer with the flight and photography functions of an unmanned aerial vehicle (UAV) and combines color band remote sensing data with ground measurement data to explore the relationship between the three levels of the urban nighttime light environment. Furthermore, a three–dimensional observation method is established for urban nighttime light environments based on a combination of three observation methods. The research results indicate that there is a good correlation between drone aerial photography data and remote sensing data (R² = 0.717), as well as between ground–measured data and remote sensing data (R² = 0.876). It also shows that UAV images can serve as a new path for the observation of urban canopy nighttime light environments because of the accuracy and reliability of UAV aerial data. Meanwhile, the combination of UAV photography, ground measurement, and remote sensing data provides a new method for the monitoring and control of urban nighttime light pollution.

The identification and distribution of urban functional zones play a crucial role in optimizing urban planning and resource allocation. The differences in brightness of the nocturnal light environment further reveal the characteristics of urban functions. This study takes the main urban area of Dalian as an example, integrates Point of Interest and OpenStreetMap data to generate functional zone samples, and proposes a multi-scale evaluation framework at the levels of administrative districts, streets, and blocks, combined with Luojia-1 night-time remote sensing imagery. The results show that: (1) Significant differences in brightness exist among functional zones within the study area, and there is a mismatch between actual demand and nighttime light brightness; (2) The Average Nighttime Radiance per Unit Area and Brightness Factor can more accurately reflect the distribution characteristics of urban nighttime light brightness; (3) Clustering based on the Brightness Factor reveals over-bright and under-bright blocks, identifying commercial and port-industry areas as hotspots of excessive nighttime lighting. This study dissects the spatial heterogeneity of the nocturnal light environment from the perspective of urban functional zoning and provides quantitative support for the development of differentiated lighting management policies.