GRD-Border-Noise and Thermal noise removal are not working anymore since March 13. 2018


#42

I think I have a similar issue - S-1 Thermal Noise removal introduces Artefacts in the image
Was a solution found to this problem?
Thanks, Sanjay.


#43

We are currently looking into this issue. Sorry for the inconvenience.


#44

Thanks Magda. I have only seen this issue in that single image take on 13th March (i.e. S1A_IW_GRDH_1SDV_20180313T180532_20180313T180557_021000_0240E0_114C), though I must admit that I have not checked every single image in details as I process several hundreds of images in batch. They look okay as such but I have no way of checking whether the values are correct after latest S1TBX fix. Sanjay.


#46

Hi, @mfitrzyk @lveci - any update on my query please. I noticed there was an update, which I did apply. However, I am still seeing the artefacts in S1A_IW_GRDH_1SDV_20180313T180532_20180313T180557_021000_0240E0_114C. Thanks, Sanjay.


#47

I’ve managed to work out what the problem is here: the java_max_mem value in snappy.ini needs to be greater than or equal to roughly 12GB in order that the IW SAFE archives can ben processed. My development machine only has 8GB and hence I was running into this problem (getting NullPointerExceptions). After testing on a machine with more memory, I found that I could reproduce the problem by setting java_max_mem to 10GB and trying to process an IW SAFE archive. This would explain why I could process EW scenes on my development box, since they don’t require as much memory and would possibly explain why others haven’t seen this issue, since one would assume they are using SNAP in an environment with 16GB or more of RAM.


#48

Thats interesting @paultcochrane - I would be interested to see if your installation can replicate the issue of data quality after thermal noise removal with the following image: S1A_IW_GRDH_1SDV_20180313T180532_20180313T180557_021000_0240E0_114C
My steps are as follows:

  1. Apply Restituted Orbits
  2. Border Noise removal
  3. Thermal Noise removal - this step produces the bad image in S-1 Thermal Noise removal introduces Artefacts in the image. I think this is related to the number 4 issue raised by @biocpu
    Thanks,
    Sanjay.