Radiometric & Geometric Correction Workflow


#41

Sorry, the results of VH is correct, but the calibrated VV are zeros.


#42

Yes, before the radiometric calibration both of the intensity of VV and VH are correct. When the radiometric calibration was implemented, the calibrated VV are zeros, and the calibrated VH is correct.


#43

I can’t think of a reason why this could happen.
Is it zero or no data /nan?


#44

What order should I take steps in ?I’ve seen one of the above threads says that it should be good after orbit to apply thermal noise removal in order to decrease radiometric variation between subswath.
Best regards!


#45

could be a good idea :slight_smile:


#46

Thanks for your reply .Do you mean orbit before thermal noise removal is better ?What are the differences between the various epolynomial degrees and which is recommended?
Thank you for help


#47

I really don’t know, sorry. Try it out and compare the outcomes.


#48

Thank you very much !


#49

Hello,
I understand the theoritical difference between beta0 and sigma0, if I want to do intensity correlation analyisis between 2 images, or in this case 3 images. I was usggested to use sigma0, however the area I am working is very hilly and has some mountains. The values of sigma0 and beta0 are ofcouse different from pxel to pixel, but only beta0 allows me to do terrain flatering.

What do you suggest I can do for my application in this case?
Thank you


#50

I then would try to correct for Gamma0 which normalizes topographic effects.
So first convert to Beta0 and then run the radiometric terrain flattening which produces ‘flattened Gamma0’.
http://ieeexplore.ieee.org/document/5752845/


#51

I want to work with Sentinel 1 … should I use these steps?


#52

Excuse me, my information is low. I can do the preprocessing process with the header. Help me more


#53

how about starting with some tutorials first?
http://step.esa.int/main/doc/tutorials/sentinel-1-toolbox-tutorials/


#54

4 posts were merged into an existing topic: How to obtain backscatter from sentinel 1 A product?


#55

The s1tbx can be used to process Sentinel-1A/B data. Does the s1tbx is open source? We want to apply some new algorithms to extract Sentinel-1A/B SAR information, thus the input of Sentinel-1A/B is necessary. Therefore, can you supply us the Sentinel-1A/B input source codes or other approach to obtain the Sentinel1A/B import codes? That is to say the sentinel-1A/B can be read. Thank you very much.


#56

https://github.com/senbox-org


#57

Otherwise there is the option of snappy with/or: http://step.esa.int/docs/v3.0/apidoc/desktop/

Petr


#58

I want to know whether I could do thermal noise removal after applying orbit file and calibration to Sigma0 or not?

Thanks for your reply in advance.


#59

I haven’t found any source, but at least before calibration seems reasonable. Orbit files have a geometric effect in the first place.


#60

Hi @lveci @ABraun,
I’m looking for help on terrain flattening for SLC.
Iv been working on change detection using (C2) covariance matrices from stacks of SLC complex images. I am experiencing some false positives over slope. Pipeline is: Orbit correction --> Radiocalibration (to complex) -->Deburst–>Multilook–>Terrain Correction.

As discussed, the GRD pipelines can normalize to gamma0 (e.g. radiocal to beta0 --> TF), but this option isn’t obviously available for complex. In fact, any normalisation under radical is not available if complex output is selected. Is there another tool like TF that i’m missing?
Much appreciated,