How do you erase items digitally?
 

I was watching the 10 minute flick school on Robert Rodriguez's Once Upon a Time in Mexico and he was showing how he used cables to hold the actors and then erased the cables in post for the scene. He even erased some people that were in a scene that were crew and not actors.

I was amazed. How do you do that on a PC? Any ideas?

Hi Dan,

You would use a compositing tool like Adobes After effects or Discreets Combustion, and simply erase the bits you do not use. However if you want more control and you have more money then I think Discreets Flame? is what I think most holywood films use.

Thanks,

Could one import the clip as still frames into Photoshop and then work on them one at a time? I've never tried this, but it seems that using Photoshop's clone stamp and healing tools one could digitally alter anything in the frame, even if the camera is not still, right? It would take a while, certainly, but if you do all the changes on a separate layer, and then modify that layer frame by frame, you wouldn't have to start from scratch every time.

Of course, I haven't actually tried this yet, so I could be totally wrong, but in theory it would seem to work.

You could certainly use Photoshop, and import a clip in .flm format. The downside, besides being extremely time consuming, is the fact that it would be almost impossible to maintain consistancy between frames.

So you can erase an entire person from a scene with adobe after effects? Then I guess you just paint in over the area where the person was erased from? After effects does that as well? The photoshop frame by frame method sounds very difficult. Is using Adobe after effects or the discreet products fairly easy? Ed have you (or anyone else) done this (erasing) before? I'm not familiar with those programs but would certainly be interested in getting one if they're that good and wouldn't take 6 months to learn how to use.

I'm actually faced with this problem but.. erasing an entire person would be quite a chore. My task is wire erasure. Unfortunately, unless that person is totally still and the scene is static, you will have to be doing lots of painting whether it is with Photoshop or with AfterEffects. With AfterEffects.. again I haven't looked at this myself .. I think there is a tracking method whereby you do one matte and then use the same object to overlay the background over the person or object you want taken out. But I think inevitably you will have to do some frame by frame painting.

Scenes with no camera movement are really easy, since you can record a backplate with no actors and then record the same thing with actors (assuming the camera stays in the exact same place with the exact same settings and the environment - light, weather, clouds, etc...are all relatively the same)...and then in After effects, set the backplate underneath and mask out the unwanted elements from the top layer, revealing the backplate underneath.

Nowadays people have gotten used to these handheld camera shots with all the elements composited seamlessly, so static shots just don't have that realism and impact.

The professionals use software that tracks feature points in a scene and 'learns' what's where. The user selects what to remove and the software overwrites it with parts of the background that it knows should be in the place of the object.
Basically, as stuff moves around, it 'builds' the background, picking bits and pieces from here and there as they become unobstructed by moving objects..


If you want to be impressed with automated object removal, check this out:

http://www.2d3.com/jsp/products/prod...duct=pixeldust

This product is mind boggling.

The price will boggle your mind as well. And I really hope it works, because support is $2000 a year, or $200 a month. There is also support @ $99 per call?

We are on the wrong end of video...

LOL!

Keith, that is true! I know a lot of us are stuck doing it by hand.

Yeah, the PixelDust guys also make Boujou ($10,000 motion tracker). But SynthEyes ($349) can do the same thing, from the reviews I have read, which makes me hope that someone like that would write an automated object-removal program that we could maybe afford.

http://www.ssontech.com/


...actually, SynthEyes supposedly has a rotoscope feature in it. I've played with the demo, but didn't try that part of it.

Anybody use this before?

Automated object removal will never happen if you want it to look
good. Why? Because a computer does not know about objects.
But I hear everyone say: what about quantum computing and
nano stuff. Let's first get there, mkay? <g>

It *IS* very time consuming and takes a lot of practice to get it
looking right etc. You can do it if you are good enough and have
enough time on your hands.

PixelFarm has PFTrack which also does this and the student price of the program is only $80. (Full price is a few thousand though).

Also, there are LOTS of ways to pull this off.
RealViz makes programs for Photogrametry that allow you to make a 3d model based on hi res photos. You can then "move" a 3d camera within the environement with data from Motion Tracker which now gives you a moving, clean background to fill in where you erase objects, even when the camera is moving.

For quick shots, I still just use the Video Paint rotoscoping tool that comes with the Media Studio Pro DV editiing suite. Having previously used the Premiere->photoshop->Premiere method, I can say that the Ulead solution is MUCH easier and faster.

I'm currently learning the RealViz tools through my visual effects training. In most common situations, especially for wires, it's not too difficult at all, even at high resolutions.

Have fun.

There are a few programs out there that will do motion tracking, which allows you to erase things in certain situations. With motion tracking, you drag select a box around a static area that the program locks onto. It will keep the whole image still, or let you move masks according to camera movement. This is effective at getting rid of logos and such with footage shot handheld.

For the guys that are rotoscoping in Photoshop, try this:

After you have selected your object, use Save Selection. Then when you load your next frame, use Load Selection and modify/move the selection to fit the object in the new frame. This keeps your mask more consistent from frame to frame, cutting back on the 'jitter'.