Thermal noise removal of Sentinel-1 HV-pol imagery in SNAP software

As we know, SNAP give a selection about removing thermal noise from Sentinel-1 imagery. However, I don’t know whether noise removal is a must by ourselves after a step in SNAP S-1 Thermal Noise Removal .

I think the results still have serious thermal contaminate after a thermal noise removal in SNAP, as following example, I have done removal but the noise is obvious.

can you please give use the full name of the product?
I don’t have a solution but I would like to try it myself.

OK. Thanks.
The image name is S1A_EW_GRDM_1SDH_20170130T154345_20170130T154445_015063_0189DC_2AFA .

But, I need to say the image thermal noise removal is using Python code( In this code, it uses thermal noise removal in SNAP module. Therefore, I regard it as processed using SNAP in my question. Sorry.

The above image has also been converted to dB value.

I’ve just tried with snap.

Top : before thermal removal
Bottom : After thermal removal
(HH polarization)

However, the preview image of the product shows these stripes

1 Like

Sorry, the image shown before is HV-pol image rather than HH-pol one. Banding effect noise is not obvious in HH-pol, this phenomenon is a problem for HV-pol images . Some papers about sea ice classification will only do incidence correction for HH-pol and thermal noise removal for HV-pol imagery.

My bad. And you’re right. If I look at HV, the stripes are huge, before AND after thermal noise removal

We can however see a difference. The last four are now ok, with the first one still much brighter

Do you know the reason of this effect? I’m interested

Yes, you are right. But the picture I given is dB value. In dB image, the phenomenon is more obvious than your result. But I don’t know the reason for your question.Sorry.

Even converted in db, we can still see the positive effect of thermal noise removal. But yes it’s far from perfect

1 Like

The paper( maybe useful to find the reason of the stripes.

1 Like

Great. It looks like Snap calibrates the data using ESA noise vectors. That is confirmed in the lines of codes of snap :

The corrections from the article are quite impressive.

I hope you will find a solution to your problem


Hello qglaude,
Did you just figure out how to solve these corrections using snap in a cross polarized (HV) channel???
If yes, can you please elaborate on how you went ahead

I have same problem too, Did you just figure out how to solve these corrections using snap in a cross for HV? Let me know too

That quite some time ago. I have no idea sorry.