When I open the meta data of the image i can see the near and far incidence angle of the whole image. I wanted individual incidence angle for each of the four polarizations so that I can plot it into a graph in X axis and the db in the Y axis for those four polarizations. Is there any way to do it? I wanted to do something like this.
What satellite data are you using?
Do you mean the incidence angle (flat earth) or the local incidence angle (topography-based)?
The first one can be found in the tie-point grids, the latter has to be calculated first, for example using the SAR Simulation tool.
Its a RADARSAT-2 data, and my work is on ship detection.
Ya I am getting the incident angle of the whole image. Can I get the incidence angle of each polarization like HH VH HV VV? all different incidence angles?
I suppose the incidence angle is the same for all polarizations.
Thank you @ABraun.
Ok I understand. So can you please tell me what does a db show? and what differences can i notice when i convert an image to db? will it show difference in intensity values or something else?
I really apologize to ask so many questions, but step forum is my last hope.
conversion to db stretches your backscatter intensity over a new value range by applying logarithm. That means, large values are shifted towards the mean and the low backscatter range (>0.2) is stretched. Consequently, your image has different contrats and some things are easier to identify.
You have to note that full backscatter (100% received signal) is at 1 in the normal image (power scale) while it is 0 in the db image (log scale).
Please also see here: Sigma0_VH vs. Sigma0_VHdb
Thank you so much. I will work on it.
I tried the search metadata method. and I end up with so many incident angles.
Do we have a mean value of the incident angle. I want to use this angle to calculate the vertical displacement.
Instead of a constant, you should use the incidence angle as a band for this task. Wr talked about the same issue here: Export for unwrapping - #29 by ABraun
Thank you for your information. I have gone through this seminar recording quickly. [RUS Webinar: Land Subsidence mapping with Sentinel-1 - HAZA03]
However, it’s based on the two radar images. Do we have a solution for the vertical decomposition of PS Insar method? I have searched around on the internet. There’s no standard process of doing it.