edward Posted November 16, 2004 Share Posted November 16, 2004 I'm putting this here hoping it will get moved to the compositing forum as I can't seem to upload files there. For the topic, please see: http://odforce.net/forum/index.php?showtopic=2339 --------- I implemented a COP VOPnet a while back based on the ultimatte equations from Jim Blinn and Alvy Ray Smith's paper, "Blue Screen Matting" (ftp://ftp.alvyray.com/Acrobat/BluSig96.pdf) which actually worked pretty well for the test images I tried. --------- If you look at the VOP network, the Parameter VOPs are named according to the paper. The workflow for using it goes something like thise: - Start off with the default parameters. - Look at the A plane of the bluescreenkey cop - Adjust each parameter in turn except for the first and last 3 until you get as good a looking matte as you can. Typically, adjust it so that you get the areas you want as white as you can and the areas you don't want as dark as you can. - Once you're done that, adjust the Lower/Upper Alpha clamp parameters to isolate the range of the alpha you want to clamp at. Typically, you just need to raise the Lower Alpha clamp value high enough so that it completely remove the blue screen. - Look at your result and then try tweaking the parameters again. Typically, I haven't found the Global Adjust parameter useful. - The last parameter can be used to add back in some blue if the matte removed too much of it. bluematte.zip Quote Link to comment Share on other sites More sharing options...
Jason Posted November 16, 2004 Share Posted November 16, 2004 Topic moved and Uploads enabled... and thanks for the upload, Ed! Quote Link to comment Share on other sites More sharing options...
sibarrick Posted November 16, 2004 Share Posted November 16, 2004 Is this something that could be put on exchange? I don't do any compositing but it sounds pretty useful Quote Link to comment Share on other sites More sharing options...
edward Posted November 17, 2004 Author Share Posted November 17, 2004 Yeah, I know. The problem is then I need to clean it up, add comments, get an account on the exchange, etc... ... Plus, I never really played with it long enough past my test images (of at most 3). Besides, there's way more interesting papers on doing matting these days (like graphcut, bayesian, optical flow, etc) that it seems hardly worth the effort on something so primitive. Quote Link to comment Share on other sites More sharing options...
MG Posted November 17, 2004 Share Posted November 17, 2004 Yeah, I know. The problem is then I need to clean it up, add comments, get an account on the exchange, etc... ... Plus, I never really played with it long enough past my test images (of at most 3). Besides, there's way more interesting papers on doing matting these days (like graphcut, bayesian, optical flow, etc) that it seems hardly worth the effort on something so primitive. 14997[/snapback] You can log in with your (SESI) forum information. Quote Link to comment Share on other sites More sharing options...
LEO-oo- Posted November 17, 2004 Share Posted November 17, 2004 @Edward: Nice work! Pretty useful - thanks! Quote Link to comment Share on other sites More sharing options...
edward Posted August 18, 2005 Author Share Posted August 18, 2005 Ok, I've just put this file up as is with a little readme up on the exchange now. http://www.sidefx.com/exchange/info.php?fi...6&versionid=226 Quote Link to comment Share on other sites More sharing options...
MG Posted October 19, 2005 Share Posted October 19, 2005 Ok, I've just put this file up as is with a little readme up on the exchange now.http://www.sidefx.com/exchange/info.php?fi...6&versionid=226 20649[/snapback] Excellent, I'm anxious to try it out myself! (As I haven't done so yet). Quote Link to comment Share on other sites More sharing options...
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