Duplication artifacts in resulting warped image

[AllenJRZhang]

Hi! Thank you for providing this implementation! Following your instructions however I noticed that the resulting warped image (I slightly tweaked your code so that run.py generates a warped image using your backwarp function) contains some duplication artifacts, as shown below:

Original Example:

Warped Image Result (Look at the blade):

Another Example:

Warped Image Result:

This did not occur with traditional optical flow estimation methods I tried or your pytorch-unflow implementation. (haven't tested the rest but will!) I wonder if it's a problem of PWC-Net itself, or this implementation specifically, or something with pytorch? Also I'd really appreciate it if you could share some insights regarding how to alleviate this problem. Thanks!