How to calculate Phase values from SIFT/AKAZE matched points for coregistration

[Tejuwi]

Hi ,
I am new to SAR technology. I am working on coregistration(Terrasarx images) using SIFT/AKAZE feature extraction techniques. I extracted matched key points from master and slave images and also calculated homography/RANSAC.
How to calculate phase values? I also want to do measure the error (pixel level) and compared to Geofloki results?
can anyone help me in this regard?

[BeijingUniversityOfChemicalTechnology]

Sorry, I am now a master degree candidate from Harbin Institute of Technology, I am also new to the field of digital image processing. Although I have studied image processing and intelligence in my graduate studies using Gonzalez's digital image processing textbook, I am still unable to answer your question.