I am testing the capabilities of SNAP to run InSAR pipelines with TerraSAR-X SM data. After importing the data into SNAP, I am running the RADAR -> Corregistration -> Corregistration step with the settings you can see below:
Did someone worked with TSX and SNAP? Any previous experience on how to better approach the corregistration? This is blocking my possibilities to use SNAP for InSAR with this satellite
Did you mean bicubic when you said bisinic? By the way, I am putting NN as resampling method in the CreateStack step. I dont think selecting Bicubic or bilinear will affect the int creation? Could you comment on this?
After corregistration with this settings, the int I get looks as random as before. As you can imagine, I have same acquisition geometry
Try first getting the coarse registration correct skipping the fine part (that you will eventually need for InSAR). Andy might be referrining to bsinc.
I was lucky with both NN and bilinear resampling in the Stack option. NN is more preservative regarding the original phase values, although it is not the predefined value.
About the resampling during the Warp step of the polynomial: I was referring to this tutorial which used TerraSAR-X data and a truncated sinc (6 point) interpolation. I mixed it up in my post above, sorry.
I would have guesses the 1st resampling method should be None, since there’s no business-reason to resample twice in a single co-registration but that is surely suboptimal. I wish I had time to try it myself…
@ABraun@mengdahl thanks for the inputs. I am using a twin mission that orbits together with TSX (PAZ) so I need a resampling method when creating the stack. I agree with you that NN is better as it affects less the original values compared to the others.
I have tried to play with the corregistration parameters as indicated in the tutorial but still the inf looks completely random. Below the settings I used now;
Not sure what you mean about it, I dont get any error on the process. Seems like some papers went for TSX processing in SNAP. Unfortunately no further details on parameter settigns are shown
About the logs, the process does not fail, it finished properly so I dont have it. The problem I am facing is that the result is not optimal. I am visually inspecting the output (comparing the intensity images in the corregistered product) and when zooming to a small subset it looks well.
Do the two images start more or less at the same location on the ground? The size of the search window is not enormous so if one image starts a bit earlier, the search might fail.
I select the corregistered product and when I open the tool I get basic info about the interferometric pair (height ambiguity, temporal, perp baseline, etc). The corregistration residuals looks empty
Radar -> Corregistration -> Corregistration.
Trying several parameters as it can be seen in the posts above. Process finishes without reporting any error. Later the interferogram is created and it looks completley random. The coherence image looks also random, so for sure something is going wrong here
Radar -> Corregistration -> Stack Tools -> Create Stack.
I dont think this is valid as for inf creation a corregistered stack is mandatory
Radar -> Corregistration -> DEM assisted corregistration -> DEM assisted corregistration
This approach does deliver a int in which fringes are now visible. Coherence also looks as supopsed. In the parameters of this tool there is not much control about the settings for coarse and fine registration, only about the DEM selection. What about this?
My doubt now is which advantage is DEM assisted corregistration bringing vs. the normal one? Is it prefered to coregister with DEM always?
Can you please create an RGB image of the coregistered product to test if both images align well?
An example is given in page 9 of this tutorial: Sentinel-1 TOPS interferometry