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How to REMOVE Green Screen using content aware?

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Nemr Abou Nassar
How to REMOVE Green Screen using content aware?
on Jun 6, 2010 at 12:48:14 am

Accurately removing green screen, especially when hair is involved, can be quite tedious :S

Does anybody have any idea if we can use the content aware tool in cs5 to remove green screen leaving everything else green screen-less?

Logically if you can remove a subject and rebuild the entire background for an image shouldn't there be a feature where you can select a background, in this cae a green one, and remove it entirely LEAVING the subject?

Any idea anyone?


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Darby Edelen
Re: How to REMOVE Green Screen using content aware?
on Jun 8, 2010 at 10:36:02 pm

Theoretically there is a process by which you could do this, but I think it's the wrong way to do it. I'll describe what I'm thinking here as a thought exercise, but you should really use channel calculations to do green screening.

What you could do is: duplicate your image twice, remove the subjects using content aware fill from the top instance, set this layer to the 'difference' blend mode and then merge it down. Desaturate this layer (cmd-shift-u) and then use levels to create a black/white mask. Select all, copy this image, apply a mask to your original image, option click on the mask and paste.

I can almost guarantee that this is not going to be pretty though based on the unpredictable results of content aware fill.

What you should do is use Image > Calculations twice:

1)
Source 1:
Layer: Merged (or your greenscreen layer)
Channel: Red

Source 2:
Layer: Merged (or your greenscreen layer)
Channel: Blue

Blending: Lighten
Opacity: 100%

Result: New Channel

2)
Source 1:
Layer: Merged (or your greenscreen layer)
Channel: Alpha 1 (your new channel from the previous step)

Source 2:
Layer: Merged (or your greenscreen layer)
Channel: Green

Blending: Subtract
Opacity: 100%

Result: New Channel

3) Go to your channels tab and make some adjustments to the 'Alpha 2' result:

a) Invert
b) Use levels to crush the blacks in the screen and boost the white in areas that should be solid

4) Create a selection from this channel

5) Apply this selection as a mask to your green screen layer


I used these two different techniques on an image I downloaded from the internet and I've attached the results. Note that this was not an ideal green screen shot as the subjects were very close to the screen (lots of spill).


'Content Aware' Technique:



Channel Calculations Technique:




Darby Edelen


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Richard Harrington
Re: How to REMOVE Green Screen using content aware?
on Jun 13, 2010 at 4:26:33 am

Stop wasting your time... totally different technology and purpose

Look up calculations command... or better yet go to AE and do key if its footage

Richard M. Harrington, PMP

Author: Video Made on a Mac, Photoshop for Video, Understanding Adobe Photoshop, Final Cut Studio On the Spot and ATS:iWork


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Tristan Chaika
Re: How to REMOVE Green Screen using content aware?
on Jun 22, 2010 at 6:50:23 pm

if you're doing this for video, definitely use the new After Effects rotoscoping tool. I haven't used it, but it looks like it can key just about anything.

If you're doing this on a still image, don't forget to try out the background eraser tool. It can give pretty good results depending on how much you want to finness it, and how high res your image is. I probably wouldn't try it on SD video footage.


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Damon Bell
Re: How to REMOVE Green Screen using content aware?
on Oct 6, 2010 at 12:58:50 am

Hi,

I just ran across this forum so I thought that I'd post.

There are obviously many ways to do this in Photoshop. I've been doing Chroma Key Photohraphy for about 5 years now.

Because I was frustrated with the plug-ins on the market, I created a script that does a decent job for most images for extraction and spill suppression. It leaves the mask and layers editable. It works with CS3 and higher.

Sometimes the images may need cleaned up slightly but its really quick and gives a good starting point.

You can download it free at http://www.photoshopgreenscreen.com.

Damon Bell


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