Small query about radarsat constellation mission product

[sparshgarg23]

Hello,I came across your repository and I am using it to learn about polarimetric sar.I have a few doubts and would appreciate if you could clarify them.
For most polarimetric sar applications,some form of pre-processing needs to be done on the raw data such as calibration,filtering etc.
In the example dataset mentioned in the python notebook,when we download it,we are presented with some xml files ,product overview and the raw data file.

Am i right in assuming that the product overview is obtained after all the pre-processing steps have been applied on the raw data,thereby implying that if i download this dataset,from my end i don't have to apply any calibration or speckle filtering ,and I can use the product overview.tiff/product overview.png file directly for further use.

Secondly,even if I wanted to try pre-processing the data on my own,how shall i go about this using python.Are there any open source resources for this?As of now,i don't see how I can generate the coherence matrix from the raw data,which I believe is an essential part for the pre-processing steps.