Shadows limitmany remote sensing applications such as classification, target detection, and change detection.Most current shadow detection methods utilize the histogram threshold of spectral characteristics to distinguish the shadows and nonshadows directly, called "hard binary shadow." Obviously, the performance of threshold-based methods heavily rely on the selected threshold. Simultaneously, these threshold-basedmethods do not take any spatial information into account. To overcome these shortcomings, a soft shadow description method is developed by introducing the concept of opacity into shadow detection, and MRF-based shadow detection method is proposed in order to make use of neighborhood information. Experiments on remote sensing images have shown that the proposed method can obtain more accurate detection results.
Li, P., & Ge, W. (2015). A Soft Shadow Detection Method Based on MRF for Remote Sensing Images. Mathematical Problems in Engineering, 2015. https://doi.org/10.1155/2015/404095