Diffuse Skylight as a Surrogate for Shadow Detection in High-Resolution Imagery Acquired Under Clear Sky Conditions

Shadow Analysis in High-Resolution Satellite Imagery of Urban Areas

High-resolution satellite imagery (HRSI) offers great possibilities for urban mapping. Unfortunately, shadows cast by buildings in high-density urban environments obscure much of the information in the image leading to potentially corrupted classification results or blunders in interpretation. Although significant research has been carried out on the subject of shadowing in remote sensing, very...

Detection of Clear Skies Using Total and Diffuse Shortwave Irradiance: Calculations of Shortwave Cloud Forcing and Clear Sky Diffuse Ratio

The effect of clouds on the shortwave (SW) irradiance near the surface is of interest for surface radiative energy budget studies (Long et al. 1994) and investigation of the recently suggested excess SW cloud absorption (Cess et al. 1995; Ramanathan et al. 1995; Pilewski and Valero 1995). One measure of the effect of clouds is cloud forcing: the difference between clear (i.e., cloudless) sky ir...

Urban Building Damage Detection from Very High Resolution Imagery by One-class Svm and Shadow Changes

A System of the Shadow Detection and Shadow Removal for High Resolution City Aerial Photo

This paper presents a methodology to automatically detect and remove the shadows in high-resolution urban aerial images for urban GIS applications. The system includes cast shadow computation, image shadow tracing and detection, and shadow removal. The cast shadow is computed from digital surface model (DSM) and the sun altitudes. Its projection in the pseudo orthogonal image is determined by r...

A Synergetic Study of Solar Fluxes and Aerosol Properties Under Clear-Sky Conditions

Several recent studies indicate that our ability to model the transfer of solar flux in the clear atmosphere is still fraught with significant uncertainties (Arking 1996; Charlock and Alberta 1996; Kato et al. 1997; Li et al. 1997; Halthore et. al 1997). The treatment of aerosol is often considered as a more likely source for the discrepancy. Presented here is an analysis of the synergy between...