Kathie said [1] "What you can do is to use methods where you [have] do not need any calibration whatsoever and you can still can get pretty good results. So here on the bottom at the top is the truth image, and this is simulated data, as we are increasing the amount of amplitude error and you can see here ... it's hard to see ... but it breaks down once you add too much gain here. But if we use just closure quantities - we are invariant to that. So that really, actually, been a really huge step for the project, because we had such bad gains. " [1] https://youtu.be/UGL_OL3OrCE?t=1177