I am working with Sentinel-1 SAR GRD images in IW swath in HH polarization. I have a few questions to ask about preprocessing and also improvement in backscatter intensity to identify ice.
I preprocess the sentinel-1 image by thermalnoiseremoval>calibration>specklefilter>terraincorrection.
My final output is a Sigma0 band.
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Before I starting with preprocessing, do I need to convert the Amplitude and Intensity to dB value or is it after I complete my preprocessing that I need to convert the Sigma0 to dB value.
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There is lot of noise in the ocean pixels and it times it is difficult to differentiate between ice and water. Is there a way to improve the differentiation between the two? The way I am thinking is to implement non-uniform filters such as “median” followed by morphological filters such as “closing” to improve the edges.
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I also tried to use gradient filter such as Sobel. However I am not sure how to implement the resultant image after sobel filteration. Can you throw some light on how to use it in combination with other filters?