I have a few question about change detection. Firstly, I use similar workflow as mentioned in the first post (GRD):
- Apply Orbit File
- Radiometric Calibration
- DEM Assisted Corregistration
- Change Detection
- Terrain correction
As was mentioned in some posts, how could I correctly select threshold to select only significant/real changes ? I know I have to play with results and I have done many change detection to examine results, but are there by your experience values which can be connected with “real” changes. Is there some value which we can consider as high/low enough to say significant change happened ? If I have log ratio values from e.g. -6 to 6.
Is there some option how to filter results ? I have tried 10 different image pairs of different areas and a huge share of changes take place in agrucultural fields or water.
Also I would like to try to do something like is described in this article.
“Using SAR Coherent Change Detection technology (SAR-CCD), change maps are generated by comparing two radar images of the same geographic region, taken at different times. This highlights areas where a significant change has occurred between the two image dates.”
It is said Coherent Change Detection is used, based on answer from another topic (below), is it the algorithm used in change detection tool ? Name of the document in the answer below is Coherent Change Detection: Theoretical
Description and Experimental Results.
Also I would like to ask, should I use GRD product (I use it now) or I should go for SLC product to get output as in the article if it could be said (resolution) ?
Thanks for your suggestions