Hi!
I want to compare the multi temporal Sentinel-1 image. I am using the Level-1 SLC sentinel-1.
How can i analyse these data for estimates the canopy loss?
how can i find the standard deviation of 4 SAR images
create a stack of the four images and use the stack averaging operator. It allows to calculate the standard deviation between the stacked images.
i create a stack. but how can i use that stack to find STDV using SNAP software
Radar > Coregistration > Stack tools > Stack averaging > select standard deviation
thnak u very much sir,can u please tell me what are the other methods to estimates forest canopy loss using SAR data
I’m not experienced with canopy measures but I would guess that this needs PolInSAR approach. The polarimetric part will cover the different scattering mechanisms (mostly volume) of the canopies and the interferometric part is for elevation difference. But this is far away from being trivial and can no longer be done in SNAP.
Maybe PolSARpro could address this, but it certainly requires specialized SAR data.
https://earth.esa.int/web/polsarpro
Some examples:
http://ieeexplore.ieee.org/abstract/document/976759/
http://ieeexplore.ieee.org/abstract/document/1025695/
http://ieeexplore.ieee.org/abstract/document/5299063/
Thank u for your quick reply. but sir i have VV polarised data only. so i cant do any PolInSAR procedures. can i compare the forest canopy loss by comparing the backscatter value of my SAR images?
with single polarized data you can’t do polarimetry.
Become familiar with the different backscattering mechanisms first.
Maybe this also gives you some help:
https://saredu.dlr.de/unit/biomass
There are plenty of other great modules as well.
Thank u very much sir
sir i did this but my output image pixel values are ranging from 0.037 to 56420.094
can this happen?
You could look at the increase in coherence if volume scatterers from the canopy are decreased. You will need at least two coherence images.