DocumentCode :
1484950
Title :
Object-Based Shadow Extraction and Correction of High-Resolution Optical Satellite Images
Author :
Liu, Wen ; Yamazaki, Fumio
Author_Institution :
Dept. of Urban Environ. Syst., Chiba Univ., Chiba, Japan
Volume :
5
Issue :
4
fYear :
2012
Firstpage :
1296
Lastpage :
1302
Abstract :
Shadows in remote sensing images often cause problems, especially in land-cover classification and change detection. Hence, it is very useful if the radiance of shadow areas is corrected to the same level as that of shadow-free areas. In this study, a radiance measurement was carried out to investigate the spectral characteristics of sunlight. Then a method is proposed for shadow detection and correction of optical imagery. First, building shadow areas are detected using an object-based classification method that employs brightness values and their relationship with the neighboring area. Next, the detected shadow areas are corrected using a linear function to produce a shadow-free image. The shadow pixels with different darkness levels are corrected by using different ratios to obtain a smoothly restored image. The proposed semi-automated method was applied to a QuickBird and a WorldView-2 images of Tokyo, Japan, to demonstrate the effectiveness of the method.
Keywords :
brightness; geophysical image processing; image classification; image resolution; optical images; sunlight; terrain mapping; Japan; QuickBird images; Tokyo; WorldView-2 images; change detection; high-resolution optical satellite images; land-cover classification; linear function; object-based classification method; object-based shadow extraction; optical imager correction; remote sensing images; semiautomated method; shadow area radiance analysis; shadow detection method; shadow-free image analysis; spectral characteristics; sunlight; Adaptive optics; Buildings; Histograms; Image color analysis; Optical imaging; Optical sensors; Satellites; Image enhancement; image segmentation; object detection; optical image processing; radiometry;
fLanguage :
English
Journal_Title :
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of
Publisher :
ieee
ISSN :
1939-1404
Type :
jour
DOI :
10.1109/JSTARS.2012.2189558
Filename :
6178286
Link To Document :
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