Advanced Optical Flow Techniques For Image Repair

August 24, 2022

Learn to use optical flow for more than speed changes. In this Insight, fix a corrupt frame and repair archival footage pull-down artifacts.


Using Optical Flow to repair corruped frames or remove non-standard film pull-down patterns

Two problems that I see regularly with my projects are single corrupted frames within a longer media file, and irregular patterns of repeated frames. This happens frequently on drone shots or archival footage that has been previously time- or frame-rate converted and needs to be cleanly re-mapped into the current timeline.

Often, both of these problems can be cleanly solved using optical flow retiming tools.

That’s right – optical flow isn’t just for slowing shots down for dramatic effect – it’s also a powerful tool for image repair. In fact, any time you want to create a brand new frame in between two clean frames, optical flow is a great solution.

Key take-aways from this Insight

By then end of this Insight you should understand:

  • When you should consider optical flow for image repair
  • How to segment out a bad frame and prepare it for optical flow
  • Why using render-in-place is important for optical flow (instead of compound clips)
  • How to apply the same technique to archival film, removing repeated frames

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Comments

Homepage Forums Advanced Optical Flow Techniques For Image Repair

Viewing 3 reply threads

    • Evan A
      Participant

      Well played Sir!


    • Jeffrey D Mathias
      Participant

      nice tip… will likely use


    • Jim Robinson
      Participant

      Nicely done Joey, while watching if I was approaching that problem in your first clip, I would have removed the frame and then looked at it like a jump cut. so my first inclination would be to try using smooth cut.
      Obviously from your final fix on this, this technique may be my new “Go To” to try to fix things like you demonstrated.
      Great insight Joey.


      • Joey D’Anna
        Participant

        Thanks! Yea a smooth cut uses the same kind of motion estimation – the biggest difference would be that no matter what your still short a frame, which in a smooth moving shot will be much more noticeable. So making a new frame really works good on those types of shots


    • Clement B
      Participant

      Create idea! I will use this technique in the future even if  I am not fully convinced. The drone shot would not pass the tech check/QC stage if that was for TV or for a show.

      I think the drone shot requires additional offset paint work to be solid. We do that a lot (using frame before & after) in VFX to fix artifacts on artificial slow motions.

      Thanks. 🙂


      • Joey D’Anna
        Participant

        Thanks!

        True – the new frame definitely isn’t perfect – a bit of manual paint and it could be. Always a balance of time vs benefit vs budget though 🙂

        I think this technique can get you to a better starting point in those cases – even if you do need to add some manual paint work on top.

         

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