Where is the use of optical flow?

[JingyeHou]

Firstly thanks for your attention. But I really have a doubt that where is the use of the optical flow? The corresponding paper illustrates that the optical flow should be used to correct the detected pose. But I failed to find it out. Is it my problem or the code problem? Please let me know. Thanks a lot!!

[williamdwl]

I meet the same problem too