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TSEC+TC: A Partitioned TSEC-Assisted Topographic Normalization Framework for Rugged Mountainous Terrain

delete2026-08-13
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OA
AI
Y
Yang Xu
X
Xiaoqing Zuo
W
Wenbin Xie
D
Daming Zhu
Z
Zhijuan Wu
Y
Yongfa Li
S
Shipeng Guo
S
Shuwei Lan
Y
Yan Luo
赵璇 (Xuan Zhao) *
DOI:10.3390/rs18162719delete
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Abstract

Abstract

En 中文
Optical remote sensing images acquired in rugged mountains are affected by reflectance distortion caused by both topography and shadows. Most topographic correction (TC) methods normalize sunlit slopes but can become unstable in self shadow and cast shadow, where little or no direct solar radiation reaches the surface. This study builds on the topographic shadow effect correction (TSEC) model and develops TSEC+TC, a partitioned framework for horizontal equivalent normalization. Using a shadow mask extended to penumbra, the framework integrates TSEC for shadowed pixels with conventional TC for sunlit pixels. Both branches target horizontal equivalent reflectance, enabling simultaneous correction of topographic and shadow effects across the scene. We implemented TSEC+TC with path length correction (PLC) and SCS with C (SCSC) models and evaluated it using ten multi-temporal Landsat 8 OLI scenes under different illumination conditions. The results showed that TSEC+TC reduced terrain-related brightness variation and improved land cover classification in the auxiliary comparison relative to uncorrected and TC-only results. For TSEC+SCSC, the R2 values between corrected reflectance and cosi were below 0.025 for both Red and SWIR1 bands, and the coefficient of variation of reflectance across aspects was consistently lower than the corresponding values for SE and SCSC, with a maximum of 36.00%. Shadow area analyses indicated that TSEC+TC compensated reflectance distortion in self shadow and cast shadow areas, reduced TC-induced outliers, and better preserved spectral patterns than TC-only correction. Tests using Sentinel-2 MSI and GF-1 WFV imagery provided preliminary evidence of applicability to other sensors. Accounting for the topographic shadow effect improved TC performance in complex mountainous areas.
Keywords:
topographic correction
shadow effect
rugged mountainous areas
optical remote sensing imagery
TSEC+TC method

Journal

Remote Sensing cover
Remote Sensing
IF:
4.1
Papers:
6.5K
Citations:
15.1W

Organization

K
kunming university
Scholars:
432
Papers: 148
Citations: 0
H
hohai university
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K
kunming university of science and technology
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