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Open AccessArticle

Terrestrial Hyperspectral Image Shadow Restoration through Lidar Fusion

1
Department of Civil and Environmental Engineering, University of Houston, 4726 Calhoun Rd., Houston, TX 77204, USA
2
Department of Earth and Atmospheric Sciences, University of Houston, 3507 Cullen Blvd., Houston, TX 77204, USA
*
Author to whom correspondence should be addressed.
Academic Editors: Guoqing Zhou and Prasad S. Thenkabail
Remote Sens. 2017, 9(5), 421; https://doi.org/10.3390/rs9050421
Received: 2 March 2017 / Revised: 20 April 2017 / Accepted: 27 April 2017 / Published: 29 April 2017
Acquisition of hyperspectral imagery (HSI) from cameras mounted on terrestrial platforms is a relatively recent development that enables spectral analysis of dominantly vertical structures. Although solar shadowing is prevalent in terrestrial HSI due to the vertical scene geometry, automated shadow detection and restoration algorithms have not yet been applied to this capture modality. We investigate the fusion of terrestrial laser scanning (TLS) spatial information with terrestrial HSI for geometric shadow detection on a rough vertical surface and examine the contribution of radiometrically calibrated TLS intensity, which is resistant to the influence of solar shadowing, to HSI shadow restoration. Qualitative assessment of the shadow detection results indicates pixel level accuracy, which is indirectly validated by shadow restoration improvements when sub-pixel shadow detection is used in lieu of single pixel detection. The inclusion of TLS intensity in existing shadow restoration algorithms that use regions of matching material in sun and shade exposures was found to have a marginal positive influence on restoring shadow spectrum shape, while a proposed combination of TLS intensity with passive HSI spectra boosts restored shadow spectrum magnitude precision by 40% and band correlation with respect to a truth image by 45% compared to existing restoration methods. View Full-Text
Keywords: lidar; terrestrial laser scanning; hyperspectral imagery; shadow detection; shadow restoration; data fusion lidar; terrestrial laser scanning; hyperspectral imagery; shadow detection; shadow restoration; data fusion
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MDPI and ACS Style

Hartzell, P.; Glennie, C.; Khan, S. Terrestrial Hyperspectral Image Shadow Restoration through Lidar Fusion. Remote Sens. 2017, 9, 421.

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