I downloaded and prepossessed Sentinel1_B images from October 2017 to April 2018 and they are all Black without any data. The Quicklook in the Open Access Hub looks fine, but there is no real data in the downloaded images. Is it something you are aware of for the period of time or specific location? An example is the filename: S1B_EW_GRDM_1SDH_20171003T123030_20171003T123113_007665_00D88D_9E57.SAFE
Thanks for your advice in advance
I just tested the image you mentioned and it is not black
Did you maybe have bad contrasts in the colour manipulation tool?
Hi this is the image that I have after regular pre-processing I did on all other data (look at the image). I have a time series from October 2017 to May 2018, I pre-processed all of them regularly and my data was ok when I used Sentinel-1A and when I get to B ones I couldn’t find anything in my data. there is a problem I think!!!
What preprocessing did you apply? Maybe you should have a look after each step to see when the issue occurs.
Thats what I really checked. My preprocssing were thermal noise removal> apply to orbit file>calibration to beta0>speckle filtering>radiometric terrain faltering>range doppler terrian.
I have all the files after each step and I checked all of them, there is something wrong with them and it is just in S1B ones. These pre-processing is what I do all the time and never had this problem!! The initial data also also should’t be like what you saw in your system. It is an area with lots of wetlands and diverse lakes and the images seems not correct!
and after which steps does the image look black?
Any chance that no DEM is available?
Thanks ABraun, When you zoom in also you can see strip borders (look at the image). Ya, I checked it. It happens after “Radiometric Terrain Flattening” ! But I did with the same setting that I did 1-A images. Any suggestion what should I do?
The only thing I can think of is that the DEM is somehow used different so that the flattening reduces the pixel value to 0. But I have no idea why this could happen.
Should I change the DEM for B ones you think?
worth a try!
Hi None of other options (DEMs) works and there are avaialble DEMs for the area. There is a problem with SNAP and Sentinel_1B, because the study area is the same and I used all the settings that I used for Sentinel-1A, if you resolved it please let me know.
@marifo What version of SNAP you use?
I’ve found some issues with ver.6 so downgraded to 5.0
The problem is that I found version 5 nonfunctional for new images and I updating it solved my problem initially, then this problem came up! I have no idea what to do! Did you have the same issue?
What is the target area? Is there land in the image?
Yes it is in Manitoba close and beyond Churchill. land with thousands of small and medium size lakes. See image below:
Mengdahl, what does the Re-grid method exactly do? The only condition which gives me not black result is when I unchecked Re-grid method. although I just tested it on one image. I want to know what exactly I miss when I unchecked it?
I am also facing this black image problem
It can have many reasons, please tell us more about your case.