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rotoscoping out a band-aid

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Loch Phillippsrotoscoping out a band-aid
by on Apr 7, 2010 at 5:51:53 pm

I am trying to remove a flapping band-aid from a dancing guy's face. I followed Tristan Nieto's excellent directions in response to a similar query. I pasted what he suggested below and here is the link:

I'm still having a problems though. I have to use several solids as Tristan directed and one is a patterned scarf. The pattern in this solid changes from shot to shot. I've tried doing this several ways, setting only one keyframe for each of the 4 gradient points, and setting several. I get the same problem of a scarf pattern overlay that changes each frame. Individual frames look great but playback shows an area where the scarf pattern seems to be boiling.

I'm not so smart with tracking or expressions, so would appreciate fix suggestions that are carefully spelled out. In Tristan's directions, I'm not sure how to Motion Track an object, so did mask my solids frame by frame manually. I don't know what he means by "find the right transfer mode for the job" and I don't know how to do the Expressions part of his suggestion.



Here is what Tristan suggested:

This might not be the answer you were looking for, but I've never had any success doing the frame-by-frame method for the exact same reason. My Best advice is to go back to AE and try the following.

Motion track the offending logo.

Make a small solid that's big enough to cover it, with a bit of room around.

Draw a mask roughly the shape of the logo and feather it. This'll probably take some keyframing, but if you can track the scale and rotation of the logo as well, this will cut out some of the work.

Chuck a 4 colour gradient filter onto your solid. Look at your video, and pick four points around the logo (but not on it) that reflect the average colour of the Golf Bag. Track these points (or just follow them manually) and then using the expressions sampleImage() expression, set the four colours on the grad filter to equal the colour of those four points on the bag.

After that, find the right transfer mode for the job, match the grain with the match grain effect and you should have something worth looking at. You could probably use this method to get rid of the jumpy jaggedies too, but this method has never let me down

Loch Phillipp
Off Ramp Films

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Tudor JelescuRe: rotoscoping out a band-aid
by on Apr 8, 2010 at 7:03:44 am

Not being able to see your shot, I can suggest a couple of solutions:
1- no tracking involved- it seems that you have a band-aid that you need removed and a scarf that is nearby. It could be that if you roto the area of the band-aid, thus creating a matte, you could composite the same clip behind, offsetting the image so that a clean part of the face and scarf show through. Again, this may not work on your shot, it depends a lot on the movement.

2- use AE's tracker (plenty of tutorials here or on the Adobe site)or if you got CS4, use Mocha (comes free, from Imagineer Systems). Apply data to a patch (solid). If the movement is 3d, then you may need to use a distortion filter (wrap or bezier) to adjust the shape

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Loch PhillippsRe: rotoscoping out a band-aid
by on Apr 9, 2010 at 2:57:01 pm

Tudor, great suggestion and thank. Have used your idea for the scarf part and the solid idea for his cheek and pea coat. Lots of mattes to cut.

It looks much better now but still has a sort of jumpy effect at times. I am thinking of putting an adjustment layer on top of this are and blurring it all some. But would love to hear other ideas for solutions on this if anyone has any.

Loch Phillipp
Off Ramp Films

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