Ghost? Gib's Phenomenon? A little help, please...

[Rain_1]

Hi again...

Last time i was here, i was asking about a derainbow filter... After lots of searches, i finally found a derainbow filter that works like i wanted to (along with other filters)... Now, i have a different problem... Well, i have 2 in fact. One is what shows up on my video and the other one is that i don't know what it's called (so i can look for ways to remove it). I've set up to pictures to show.

http://rain01.free.fr/cap/ghost1.png
As you can see on that pic, looks like there's a ghost of the image shifted to the right (or a shadow? I don't know what to cal).. you can clearly see it going along every single black line, specially on the left kid's orange suit.

Yes, i'm aware of all the blocking and rainbowning (not apparent) on that video, but that's an undoctored picture. The following script (which i got from http://forum.doom9.org/showthread.php?t=102162&highlight=trigun and modified a bit) successfully clears it all up. My only problem is the ghosting/shadowing/whatever is it named.

LoadPlugin("c:\avs\TIVTC.dll")
LoadPlugin("c:\avs\Bifrost.dll")
LoadPlugin("c:\avs\fft3dfilter.dll")
loadplugin("c:\avs\awarpsharp.dll")
LoadPlugin("c:\avs\guavacomb.dll")
LoadPlugin("c:\avs\MaskTools.dll")
Import("d:\LimitedSharpen.avs")

AviSource("d:\sealab1113 cortado.avi")
GuavaComb(Mode = "PAL", Recall = 75, MaxVariation = 25, Activation = 40)
TFM(mode=6,PP=7,slow=2,mChroma=false)
TDecimate(mode=1)
ConvertToYV12
BiFrost(interlaced=false)
FFT3DFilter(sigma=1,bt=3,bw=32,bh=32,ow=16,oh=16)
Crop(32,2,-18,-4)
aWarpSharp(depth=16,cm=1)
Lanczos4Resize(640,480)
LimitedSharpen()

Here's a second pic that elaborates on how the ghosting is different deppending on the color being displayed - you can see it clearly on the sailor's hand at the right, but it's not so apparent on his black clothes down his arm.

http://rain01.free.fr/cap/ghost2.png

Any ideas on what that's called and which filter would diminish/remove them?
Thanks in advance.

PS.: I linked the pictures instead of pasting them because each .png is 450k ish...

[trevlac]

Blur or a smoother. You could even try to do a bilinear size down and then back up.

It does sure look like that ringing stuff I sometimes read about :) Interesting that it is not on both sides of the image.

You could even try some fancy mask based upon contrast ... kind of an unsharpen mask thing ...

In the end you need to blur.

[Rain_1]

Could you please point out some avisynth plugins that i could use?
I'm not that smart when it comes to avisynth plugins knowledgement.. :(

[mg262]

I would also have a go with the VirtualDub plug-in Exorcist for this. You can import it into AVISynth if you want. (There is an AVISynth port called GhostBuster, but I found it to be buggy. Also, the VirtualDub preview is really useful in this case.

[Chainmax]

Search no more my friend, for I will bestow upon you the best halo remover this forum has ever seen. It's better than HQDering because it doesn't produce aliasing, it's better than FixVHSOverSharp because it doesn't produce flickering and it's better than the BlindDeHalo line because it doesn't kill detail and oversmoothes. Behold the might of DeHalo_Alpha (http://forum.doom9.org/showthread.php?t=102794&page=3&highlight=DeHalo_Alpha)!!
What TV standard do you have? This might be field blending instead, and that requires a whole different treatment.

By the way, foxyshadis made a version of SmartSSIQ that works with the avisynth version which is probably much faster since it avoids converting to RGB. You can download it from here (http://forum.doom9.org/showthread.php?p=744689#post744689).

About BiFrost, it's an awesome rainbow remover, but you have to use it correctly. You have to know wether the rainbows are type1 or type2, i.é if you have to use Bifrost before or after IVTC. Read its readme for instructions on finding out which kind your source has.

Why are you using GuavaComb, by the way? If it's for DotCrawl removal, I recommend you to use DeDot_YV12 (http://nullinfo.s21.xrea.com/#DeDot_YV12) instead, it's highly regarded in this forum. Just make sure you put it before IVTCing or deinterlacing

If you have any doubts on how to use avisynth functions on your scripts, don't hesitate to ask :).


P.S: what's up with those lines in the ghost2 picture? Is that some kind of interference?

[mg262]

IMO this isn't halos per se... it's a per-scanline (i.e. purely horizontal) effect caused by loss of high-frequency information, as e.g. happens when you store things on VHS. It shows up on sudden luma changes as you traverse the scanline from left to right. It is more apparent on the hand because the luma change (from pale hand to black line) is larger than that on the clothes (dark clothes to black line).

[Chainmax]

Well, I imagine FixVHSOverSharp is tuned for this kind of artifacting, and DeHalo_Alpha beats it handily at this task.

[Richard Berg]

Why are you using GuavaComb, by the way?
For rainbows caused by comb artifacts, it's a great filter. The only real flaw is that it takes a few frames to kick in after each scene change. Makes sense considering it was written for realtime use; for hardcore AVS processing it should be possible to work around at the expense of speed, either by hacking the code or clever scripting.

[Chainmax]

I know that, but since he also used BiFrost I assumed he was using it for DotCrawl.

[charleski]

IMO this isn't halos per se... it's a per-scanline (i.e. purely horizontal) effect caused by loss of high-frequency information, as e.g. happens when you store things on VHS.This looks very much like analog transmission ghosting, usually caused by your antenna picking up a stray reflection of the signal a few milliseconds after the main one, though it can happen with poorly-terminated cables as well.

What you really want to do is take a copy of each frame, shift it to the left by an amount that matches the ghosts and then subtract a percentage of it.

[mg262]

What you really want to do is take a copy of each frame, shift it to the left by an amount that matches the ghosts and then subtract a percentage of it.This is what Exorcist does.

[Chainmax]

I'd still rather try DeHalo_Alpha first before using a VDub filter and incur in a costly conversion to RGB and back.

[twonky]

Where would DeHalo_Alpha be placed in a script, i.e., in regard to IVTC/denoising/deringing filters? And do you recommend deringing in conjunction with it? Thanks for any assistance here.

[Chainmax]

Well, I always use halo removal after resizing because the most common resize methods sharpen the picture a bit. After halo removal, I might add sharpening if needed. About deringing, that a different issue: ringing can be used to describe halos and some kind of noise if I'm not mistaken. For the halos, you already have DeHalo_Alpha, and for the noise, you will probably already have used a denoise filter. So, on a general basis, I wouldn't use deringing aside from halo removal. Remember that it depends on the source though.

[trevlac]

@Rain_1

How did you obtain the images? I'm interested in all the theories here ... but knowing a little more about the source would be nice.

My (wild) guess is that it is cartoon network from satellite recorded on a vcr and then captured via a DV device ... :)