Model can align any frames

[EricMingze]

Hi, thanks for your work. I found a pretty weird problem when I was testing the alignment module. I found the alignment module can align any frames even if they are totally unrelated.
support frame:

reference frame:

I tried to align the above two frame, and I expect the output to be a mess because these two frames are totally different. However the result is very similar to the reference frame. Is this because the information of the reference frame is leaked during alignment?

result:

Thanks.

[YapengTian]

Wow!!! Really interesting observation! From the formulation of the deformable alignment and implementation in the code, we can learn that the reference frame is only used for generating deformable offsets to decide where to sample on the supporting frame. So, I think there should not be an information leaking issue.

Deformable alignment is performed at a feature level, which is different from optical flow-based warping. So, there are transformations over supporting features on the predicted sampling positions. This could be the one reason why we can
obtain this result.