Object Removal with shaky cam and a truck out.

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Object Removal with shaky cam and a truck out.
by Teresa Leong on Sep 20, 2011 at 10:14:18 pm

Hey Everyone,

This might be a very amateur question (but I am an amateur!). I've been working on object removal on this short for the past week, and based of a tutorial I found somewhere on the internet this is what i've been doing in After Effects:

I have been using After Effects CS5.5

-Roto/Mask out the offending object on one layer of the footage.
-Take another copy of the footage and move it over so that it seems offending object is no longer in the way
-add various effects to the footage copy to match the original

It worked for 3/5 shots I was working on, but then I ran into a more complicated situation. The Camera is now shaky and trucks out. So now when I use my previous method (i'm replacing telephone pole crossbars with the mountain in the BG) the mountain looks like it's awkwardly moving in that one spot. I've looked through the tutorials here/and other forums and they all suggested:
-Fixing the frame in photoshop
-Roto out offending areas
-Add some effects to match the two layers.

This method sounds all good and fun, but how do i make a clean plate with a truck out? and then match that image back to the original footage?

If someone could answer this problem soon I'd really appreciate it! I'm supposed to hand these files over in 12 hours!!!

Help! Thanks for reading!

Here's the original footage to give you some ideas on what I need to do. As I said the crossbars have to be removed:
http://reels.creativecow.net/film/crossbars-removal

Here's a similar shot where the guy on the left walks over. Any further suggestions on how to remove those crossbars would be awesome!
http://reels.creativecow.net/film/guy-walks-over

Thanks again!

Teresa

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Re: Object Removal with shaky cam and a truck out.
by Roland R. Kahlenberg on Sep 21, 2011 at 2:01:05 am

[Teresa Leong] "This method sounds all good and fun, but how do i make a clean plate with a truck out? and then match that image back to the original footage?"

To create a clean backplate for re-insertion, you look for the frame where objects to be removed appear the largest on the shot.

The workflow would be something like this -
1) identify frame to be cleaned
2) clean a single frame (since the object to removed isn't animating organically; similarly with the background it is on). It's ideal to clean up a little more than is necessary, in terms of area
3) use Mocha to track a plane on which the object exists. Ensure that Mocha's Surface more than covers the area to be cleaned
4) export CornerPin Data to AE - TIP (use Mocha's Align Surfaces feature prior to export. Ensure that the frame that you apply Align Surface matches the frame that you created the clean backplate.) Apply the Corner Pin data to the clean patch NOT the entire clean plate. Place the original image below to check the composite. Apply Add Grain to match grain between the static patch that you created and the original video.

If all goes well then look at roto-ing the foreground object.

5)) use Mocha to track any other foreground objects that need to be rotoed. Export Shape Data to AE.

For the camera pullback shot, the wires can be cleaned with a quick key of the blue sky coupled with a quick mask (for the wires) and replaced with a similarly coloured sky.

The other shot should follow the same logical process with the roto-ing part being a more involved process.

HTH
RoRK

Intensive AE & Mocha Training in Asia.

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Re: Object Removal with shaky cam and a truck out.
by Teresa Leong on Sep 21, 2011 at 2:17:25 am

Hey Roland,

Thanks for the reply. Do you know of any good Mocha tutorials? I've never used that program before...

I watched some of curious turtle's tutorials, but he doesn't do a good job explaining things to a total newcomer. So if there are any good ones you know of please let me know :)

Again thank so much for the reply!

Though out of curiosity there isn't a way to do with without Mocha is there? I'm not against to learning new things, but I'm not sure if I can learn Mocha and get all this done by tonight!

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Re: Object Removal with shaky cam and a truck out.
by Roland R. Kahlenberg on Sep 21, 2011 at 5:39:57 am

[Teresa Leong] "Do you know of any good Mocha tutorials? I've never used that program before"

If your deadline is tonight then you're going to have issues learning Mocha. You will need to get the insights into planar tracking, Mocha's Surface Area, Mocha's 'link to track' feature, Mocha's Align Surface feature.

And I'm having second thoughts on using a Sky Replacement technique for the wires. My thoughts now are to use AE's Clone Tool and this involves using at least two instances of the Clone Tool - a big brush to clean up the areas that do not require finessing (higher up areas) and then a smaller brush for the areas just over the mountain.

Do take note that Camera Projection is another viable solution but that involves 3D matchmoving. It's actually a lot easier, in terms of the number of procedures you will have to jump over but if you know 3D matchmoving then perhaps that is a better solution.

You will want to look at the Imagineer System's site for Steve Wright's Mocha tutorials. I'm having technical issues on my end trying to connect you to Steve's Mocha tutorials on the said. You should be able to get there on your own.

Having a deadline a few hours away for a very advanced AE technique isn't exactly ideal for an amateur. But I'm sure you know better. ;-)

Cheers
RoRK

Intensive AE & Mocha Training in Asia.

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Re: Object Removal with shaky cam and a truck out.
by Roland R. Kahlenberg on Sep 21, 2011 at 10:30:10 am

BTW, I forgot to mention that MochaPro's Remove Module will very likely do the job in a single pass and without having to create a clean plate.

HTH
RoRK

Intensive AE & Mocha Training in Asia.

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Re: Object Removal with shaky cam and a truck out.
by Teresa Leong on Sep 21, 2011 at 12:19:47 pm

Thanks a lot!

I managed to finish the first shot semi decently, but at least now I need to know what I should learn in Mocha to continue on with my vfx work.

Thanks a whole bunch. Hoping to figure out how to get the Second shot done in the next 24 hours...I was just gonna follow what you had posted and prayed everything would work out.

Thanks again!

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Re: Object Removal with shaky cam and a truck out.
by Roland R. Kahlenberg on Sep 21, 2011 at 5:07:35 pm

I'm glad it's working out for you. The technique for the second shot should be analogous to the first with the exception that roto-ing the foreground object will be trickier since it's a moving object.

You should however be able to track the foreground object in Mocha with a loose shape and then use another Mocha layer with a tighter shape for use as a mask/matte in AE. Once the loose shape layer tracks sufficiently well, you then create the tighter shape on another Mocha layer and simply link the 'tight layer' to the 'loose layer'.

Hope that makes sense.

This is the workflow for linking shape layers to tracked layers in Mocha. Again, there are tutorials on the Mocha site.

Cheers
RoRK

Intensive AE & Mocha Training in Asia.

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Re: Object Removal with shaky cam and a truck out.
by ben g unguren on Sep 21, 2011 at 2:48:47 am

I'll second RoRK on that. I just used asimilar technique to remove collars off the necks of several animals. It's a lot of work but it's quite effective.

Ben Unguren
Motion Graphics & Editing
http://www.mostlydocumentary.com

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