Pedosphere 18(1): 124--130, 2008
ISSN 1002-0160/CN 32-1315/P
©2008 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Empirical line method using spectrally stable targets to calibrate IKONOS imagery |
XU Jun-Feng and HUANG Jing-Feng |
| Institute of Agricultural Remote Sensing and Information Technology, Zhejiang University, Hangzhou 310029 (China). E-mail: Junfeng_xu@163.com |
| ABSTRACT |
| By using spectrally stable targets, the empirical line (EL) method was tested to correct the multispectral IKONOS imagery acquired over Putuo Mountain, Zhejiang, China. A series of calibration targets, which were spectrally stable over time, were selected to establish the linear predicted equation. Subsequently, a series of spectrally stable validation targets were selected to assess the accuracy of the equations. And, validation targets, which were spectrally unstable over time, were used to test the feasibility of using the EL method to calibrate the archival remotely sensed data. Ground reflectance measurements for each target were made using an ASD FieldSpec spectroradiometer. A Trimble GeoXTTM GPS unit with sub-meter accuracy was used to estimate the target position accurately. Linear regression equations for four IKONOS bands were derived. The coefficients of determination for the blue, green, and red bands were all greater than 0.9800 and it was 0.9697 for the near infrared band. It was concluded that reasonable results could be obtained by using spectrally stable targets. |
| Key Words: calibration, empirical line method, IKONOS, spectrally stable targets |
| Citation: Xu, J. F. and Huang, J. F. 2008. Empirical line method using spectrally stable targets to calibrate IKONOS imagery. Pedosphere. 18(1): 124-130. |
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