Remove artifacts from automatically created mask

Adobe After Effects

Remove artifacts from automatically created mask

Posted by Josh Zarno on May 30, 2011 at 9:28 am

Hey guys,

First post, love the community been a great help expanding my knowledge base so far, but have struck a problem haven’t been able to fix. If anyone has a workaround or plugin I could maybe purchase to help I would be much appreciative.

Setup
Difference Matte Comp – Basic difference matte leaving only the difference black and white image (black being the areas of the original shot to negate). Basic mask around the moving entity to try and remove grain from matte added.
Entity Comp – A luma matted version of the original shot using the difference matte comp; showing only the entity (and shadow etc) with the backdrop being white.
Output Comp – Comp with freeze framed backdrop and multiple copies of entity comp having keyed out the white backdrop.

QUESTION
a) Is there a way to remove the grain from the shot surrounding the entity without masking every frame perfectly?
b) Is there a way of adding areas removed from the difference matte if the levels adjustment wont work?

I am basically trying to form a workaround for creating a close-enough-to-perfect matte for action footage sequences without cropping every frame around the object. I am attempting to recally long lost knowledge and failing miserably, any help would be appreciated.

Regards,
Josh

Roland R. kahlenberg replied 15 years ago 2 Members · 5 Replies
5 Replies

Roland R. kahlenberg
May 30, 2011 at 2:31 pm

Once you’ve got the Difference Map to generate a luminance image, you should use the luminance image as a track matte for any grain removal procedure.

QUestion 2 is best answered only after seeing what you have. Try to share with us a few snapshots of your comp setup as well as each layer, individually.

Cheers
RoRK

AE Training in South East Asia. AE templates for sale and rental. Click here for more
Josh Zarno
May 31, 2011 at 7:17 am

Thanks for your reply Roland. I believe what you suggested has already been done, the luminance image sequence has been precomposed for use in conjunction with attempting to remove the grain. Its the process of removing the grain that I am having so much difficulty with, as all the settings in regards to creating the luminance matte are so minute the grain cannot be removed effectively.

Here are the some snapshots as requested:

a) The overall render highlighting the grain output_with_grain.jpg

b) The luminance matte (showing the basic masking) luma_matte_basic_masking.jpg

I am attempting to formulate a method by which action sequences can have a background removed easier then masking each frame, I fear that this is as close as I will get to achieving that goal with this method.

Josh
Roland R. kahlenberg
May 31, 2011 at 9:57 pm

Hi Josh, the grain looks more like a processing artefact than grain. Try a matte choker to remove the dots/grain.

I think you may want to have a look at Carl Larsen’s COW TUtorial – https://library.creativecow.net/articles/larsen_carl/analyzing_motion.php which seems to accomplish something similar to effect in your video.

HTH
RoRK

AE Training in South East Asia. AE templates for sale and rental. Click here for more
Josh Zarno
June 3, 2011 at 3:12 am

Brilliant!!

Much thanks Roland, I had already dabbled in stromotiom, not what I was looking for but none the less you have been a great help, I have achieved what I was looking for having developed a better procedural matte and have had great success replicating the technique in a few different scenarios.

Much thanks!
Josh
Roland R. kahlenberg
June 3, 2011 at 11:10 am

I’m glad you sorted it out Josh. And thanks for reporting back. It’ll be double sweet if you could post a vid or two.

Cheers
RoRK

Intensive AE Training in South East Asia.

Reply to this Discussion! Login or Sign Up

Creative Communities of the World Forums