Oil spills revealed as a set of dark patches in Sarge imaged physically due to its damping effect on capillary
waves and short gravity waves on the sea surface which are dominant in the process of Bragg scattering (Miglioccioet al., 2005). The damping ratio of spilled sea surface varied from -4.12dB~-7.20dB in L band, C band and X band SAR images according to the computation in a simulated oil spill SAR image (Franceschetti et al., 2002).To analyze
the detection of oil spill by HJ-1C SAR image, two typical oil spill objective imaged by HJ-1C SAR (ID 2 in Tab. 3)
in December 2012 and by Envisat ASAR in September 2011 were choosen respectively, which were interpreted as
of resambled features (e.g. sea state, shape and location of released oil, distance from the coast to the spilled spot,
and etc.). It was worthy to notice that the analysis of oil spill images was basically based on the the intensity SAR
images as the absence of the calibration constant of the HJ-1C SAR data. Firstly, ENVI (version 4.8) software was used to process the above two SAR intensity images into 8-bit resampled, as shown in Fig.2a and Fig. 2c. Then, the 3 by
3 Frost enhancing filter, with the damping factor of 1.0, was applied to suppress the speckle noise of the intensity images. Finally, three Regions Of Interested (ROIs) labelling in yellow rectangles were selected within HJ1-C and Envisat ASAR images respectively, as shown in Fig.2b and Fig. 2d. The statistical histograms of the pixel’s Digital Number (DN)
values of the ROIs were plotted in Fig.3.