Geoinformatics Unit

Paper accepted for publication in ISPRS Journal of Photogrammetry and Remote Sensing

September 4, 2019

Our paper entitled "Blind Cloud and Cloud Shadow Removal of Multitemporal Images Based on Total Variation Regularized Low-Rank Sparsity Decomposition" written by Yong Chen, Wei He, Naoto Yokoya, and Ting-Zhu Huang has been accepted for publication in ISPRS Journal of Photogrammetry and Remote Sensing.

Cloud and cloud shadow (cloud/shadow) removal from multitemporal satellite images is a challenging task and has elicited much attention for subsequent information extraction. Regarding cloud/shadow areas as missing information, low-rank matrix/tensor completion based methods are popular to recover information undergoing cloud/shadow degradation. However, existing methods required to determine the cloud/shadow locations in advance and failed to completely use the latent information in cloud/shadow areas. In this study, we propose a blind cloud/shadow removal method for time-series remote sensing images by unifying cloud/shadow detection and removal together. First, we decompose the degraded image into low-rank clean image (surface-reflected) component and sparse (cloud/shadow) component, which can simultaneously and completely use the underlying characteristics of these two components. Meanwhile, the spatial-spectral total variation regularization is introduced to promote the spatial-spectral continuity of the cloud/shadow component. Second, the cloud/shadow locations are detected from the sparse component using a threshold method. Finally, we adopt the cloud/shadow detection results to guide the information compensation from the original observed images to better preserve the information in cloud/shadow-free locations. The problem of the proposed model is efficiently addressed using the alternating direction method of multipliers. Both simulated and real datasets are performed to demonstrate the effectiveness of our method for cloud/shadow detection and removal when compared with other state-of-the-art methods.

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Cloud/shadow removal results for the second real Sentinel-2 dataset on time node 1. (a) Cloud/shadow image, (b) MC, (c) ALM-IPG, (d) AWTC, (e) TVLRSDC (our method), and (f) estimated cloud/shadow component by TVLRSDC.