Test functionality Equivalence Post vb.net to c# migration

I have a huge codebase migrated from vb.net to c#. Can you please suggest how can I automate to test functional equivalence between the vb.net and c#

Primarily I am looking for computer vision technique image comparison - For example may be using computer vision technique..compare a specific form screenshot in vb.net against the same form screenshot in c# and check if all the buttons, text boxes, labels are migrated. The screens are not perfectly aligned therefore the image comparison results are not good.

Or there can be other any way

Request for help. Thanks