JanBing
21st October 2004, 02:01
I know, this question has been asked a million times on these forum, but searching through all the "how to remove ghosts"-threads on this forum didn't bring up any help to my problem. I guess an image is the best thing to start with:
http://www.scummbar.com/mi2/temp/anh2.gif
The original is an analog capture from a laserdisc. As you can notice, it has some ugly ghosting-halos on the left side of edges. I tried to eliminate these halos using the VirtualDub-filter "Exorcist", which, on the first sight, appeared to work perfectly (the image is just a little noisy, since it's a 256-color GIF).
Anyway, upon closer inspection, and after some (necessary) color correction, the Exorcist filter didn't turn out to be as good as hoped. Have a look at the next images (the right parts have been brighten up to show the problem more clearly):
http://www.scummbar.com/mi2/temp/oldnew1.gif
http://www.scummbar.com/mi2/temp/oldnew2.gif
You see, there's an "old" and a "new" method... the old one is the approach shown above, using "Exorcist" in VirtualDub. Unfortunately, after some color correction it becomes obvious, that Exorcist isn't all that great, since (by shifting luminance to remove halos) it creates a new set of halos, like the ones left of the face, and in the black areas of the arm on the lower image.
Now, I thought that it would be enough to just remove the bright halos, and so I created an AviSynth-script containing the Overlay-filter in its "Darken"-mode. You can see the result above as the "New method". By using the "Darken"-mode it only takes care of bright halos, and leaves the dark halos untouched... and I thought, since they're in the dark areas of the image, they're less ovious and hence negligible. Well, obviously I haven't thought it all through...
http://www.scummbar.com/mi2/temp/anhx.jpg
The bright halos are gone, but bright areas are still casting dark ghosts upon darker areas... like the two suns onto the sky.
Now, is there a way to REALLY remove these ghosts?
http://www.scummbar.com/mi2/temp/anh2.gif
The original is an analog capture from a laserdisc. As you can notice, it has some ugly ghosting-halos on the left side of edges. I tried to eliminate these halos using the VirtualDub-filter "Exorcist", which, on the first sight, appeared to work perfectly (the image is just a little noisy, since it's a 256-color GIF).
Anyway, upon closer inspection, and after some (necessary) color correction, the Exorcist filter didn't turn out to be as good as hoped. Have a look at the next images (the right parts have been brighten up to show the problem more clearly):
http://www.scummbar.com/mi2/temp/oldnew1.gif
http://www.scummbar.com/mi2/temp/oldnew2.gif
You see, there's an "old" and a "new" method... the old one is the approach shown above, using "Exorcist" in VirtualDub. Unfortunately, after some color correction it becomes obvious, that Exorcist isn't all that great, since (by shifting luminance to remove halos) it creates a new set of halos, like the ones left of the face, and in the black areas of the arm on the lower image.
Now, I thought that it would be enough to just remove the bright halos, and so I created an AviSynth-script containing the Overlay-filter in its "Darken"-mode. You can see the result above as the "New method". By using the "Darken"-mode it only takes care of bright halos, and leaves the dark halos untouched... and I thought, since they're in the dark areas of the image, they're less ovious and hence negligible. Well, obviously I haven't thought it all through...
http://www.scummbar.com/mi2/temp/anhx.jpg
The bright halos are gone, but bright areas are still casting dark ghosts upon darker areas... like the two suns onto the sky.
Now, is there a way to REALLY remove these ghosts?