Unknown artifact to me

[Anakunda]

Greetings,

anybody can determine what is this artifact, and what filter/tool is available to remove it?
Thanks in advance

http://img215.imageshack.us/img215/473/artifact.png

[CWR03]

I think it's called strobing, where the pattern of the shirt interacts with the sensor of the camera. I'm pretty sure that once it's in the source it's there for good.

[Anakunda]

yes it is due to stripes on the shirt as the fields only appear on the man's shirt in the movie, and as I can see they are present on the DVD too
however I was hoping there's a filter or avisynth command or something that can remove the fields digitally
anyway thanks for the information

[Blue_MiSfit]

Try this:


fft3dfilter(plane=3, sigma=4)
gradfunkmirror(1.51)


Just a shot in the dark....

[Soulhunter]

Moire?

[poisondeathray]

Moire?

Exactly.

Color moire occurs very frequently with videos shot with DSLR cameras (not that this particular source was shot with those, it looks too dated for that).

One approach people use to improve this is to blur the chroma , and then increase saturation a bit. It's not a great fix because the colors become desaturated /resaturated disproportionately

This was done in After Effects, but I think there should be something equivalent in avisynth or vdub filters

http://i46.tinypic.com/sdhhjd.png

[Ghitulescu]

Color moire occurs very frequently with videos shot with DSLR cameras (not that this particular source was shot with those, it looks too dated for that).

Why would a DSLR yield moiré effects? Why would therefore one pay 2000€ for such a camera, when a 23.99€ Chinese one performs better? Sorry if I did wrongly understand...

PS: I own a DSLR (an expensive toy) and never saw any moiré ...

[Anakunda]

This was done in After Effects, but I think there should be something equivalent in avisynth or vdub filters

I don't have AE but is this fix possible by Vegas or some of it's plugins ?

[poisondeathray]

Why would a DSLR yield moiré effects? Why would therefore one pay 2000€ for such a camera, when a 23.99€ Chinese one performs better? Sorry if I did wrongly understand...



PS: I own a DSLR (an expensive toy) and never saw any moiré ...


What model? I would guess you probably haven't used it very much. They all exhibit it to varying extents. Some are a lot worse than others (e.g. 7D). You can have a quick look at various DSLR video forums this is a well known issue.

The basic explanation is they subsample pixels from the larger array. Your stills have a larger resoultion than your videos, but both use the same sensor. The processing isn't enough to process it properly at that high res. Think of the fastest burst mode using stills, you can only get 5-6fps right? If you could shoot 24fps, you could get 24fps video then. In order to shoot video at 24-30fps, it line skips or samples every "n" pixel. So you get jaggies and moire.

Certain shots are more prone than others. Brick walls, picket fences, tiles on a roof, striped shirts. Anything with repeating patterns. Wide shots are more prone. There are ways around it too, like defocusing, using anti moire and anti aliasing filters which you can buy.

[poisondeathray]

I don't have AE but is this fix possible by Vegas or some of it's plugins ?

I'll have a quick look and report back if I find anything for vegas

To re-iterate, all I did was a chroma blur , then increase the saturation a bit. If you really wanted to you could rotoscope or mask out areas so the filter is only applied to those sections (not harming the "good" sections)

I can't think of the equivalent avisynth function for the chroma blur, but hopefully one of the avisynth experts can chime in

EDIT: yes vegas does have something similar. It's not quite as good, but still a definite improvement. You can apply several instances of "chroma blur" using the maximum blur preset. As with AE, you might want to bring the saturation up a bit after

[Gavino]

I can't think of the equivalent avisynth function for the chroma blur
v = ... # source video
x = 1.0 # blur amount, change as reqd
YToUV(v.UToY().Blur(x), v.VToY().Blur(x), v)

[Motenai Yoda]

removegrain(0,12) ? or 0,20 fast but radius = 1

or

mergechroma(last,last.blur(1))
u can use binomialblur instead of blur to give bigger radius than 1.58
or

smoothuv

with smoothuv(radius=7)

http://img192.imageshack.us/img192/9783/testpvv.png

[Soulhunter]

Why would a DSLR yield moiré effects? Why would therefore one pay 2000€ for such a camera, when a 23.99€ Chinese one performs better? Sorry if I did wrongly understand...

PS: I own a DSLR (an expensive toy) and never saw any moiré ...
Thing is, the anti-aliasing filter (http://dpanswers.com/content/tech_defects.php#moire) in DSLRs is picked for photo resolution,
which means its too weak for the much lower video resolution...


Solutions:

- Learn to work around it (its possible)
- Demand DSLRs with inbuild dual or replaceable AA filters
- Demand stronger AA filter in DSLRs (but this will result in blurry photos)
- Buy a dedicated video camera (one at the same level as a 2000€ DSLR will be very expensive!)

[Ghitulescu]

I don't think this is fully off-topic, however:

After being prompted by poisondeathray I've spend the WE searching the net and read many hundreds of posts and articles.

The facts:
1. 80% (I think) concern Canon only, directly or indirectly (that is, the issue is generally described, but only Canon is given as example!!!).
2. Most authors belong to the amateur class, and they bought their Canons thinking: Well, the new Canons are as good as the old models, cost less, have more pixels, and can shot movies. Wow!
3a. Canon manufactures also camcorders, some of them are FullHD, some of them have an 8Mpixels CMOS sensor, some of them feature the DIVIC processor - one model that has all these features is Legria HFS20 (Vixia in the States I think)
3b. The filming-DSLRs from Canon also have the DIVIC processor, and some models are also 6MP to 10MP (I don't think they had an 8MP DSLR).
4. In EU, a photocamera cannot shot more than 30 minutes otherwise it will be considered a camcorder, thus an extra tax will be levered. This issue is not said in the shops, most of the time not even in the UserManuals, the sellers don't know or want to say.
5. Shooting 24fps is not possible with any DSLR (I think 10fps is the maximum), because of memory and transfer restrictions - think of the fact that a DSLR should capture RAW, ie large amounts of data should be stored and transferred. This is why compression (AVCHD) was invented, right?
6. the issue is less present in any Nikon or Nikon based DSLR (Kodak, Fujifilm), but is again present in, isn't this a big surprise, Sony based ones (as Sony also manufactures HD camcorders :rolleyes:)...

Why can an 8MP HD-camcorder show no sensible moiré and a 6MP DSLR (both CMOS, both Bayer-Pattern), employing the same DIVIC (processing power) but having a better optics, do? Why, why, why, I wonder why?

So, if Canon manufactures a DSLR that shoots as well as it takes photos, an apparatus that has to be cheap (well, in its class range) or Nikon/Olympus/Sony and the newcomers Panasonic/Samsung will overtake the market share, in other words as cheap as it's HD camcorder pendants, wouldn't this be a shot in its own leg?

So the marketing said: ok guys, you'll have a DSLR which has the main purpose that of having good RAW pictures, occasionally you may use this for filming, but hey, if you want a good camcorder, please buy the camcorder! The same goes vice-versa for the photo shots of the camcorder.

This is the world according to Ghitulescu :rolleyes:

[poisondeathray]

The facts:
1. 80% (I think) concern Canon only, directly or indirectly (that is, the issue is generally described, but only Canon is given as example!!!).


Not sure where you get 80% or how relevant that is. It certainly is worse in some models (7D esp.) , but I think what you're seeing is there are many more users who use Canon models for video, so it gets reported more frequently. The 7D and 5D have sold many models; the 5D almost single handedly started the "DSLR" for video revolution.

It affects all models that have high MP stills (17-21MP), yet deliver 2-3MP for video. It's the sampling that is causing the aliasing, and related, moire. The processor isn't good enough to do a proper resize, so they "line skip" or take every "n"th pixel.


3a. Canon manufactures also camcorders, some of them are FullHD, some of them have an 8Mpixels CMOS sensor, some of them feature the DIVIC processor - one model that has all these features is Legria HFS20 (Vixia in the States I think)

3b. The filming-DSLRs from Canon also have the DIVIC processor, and some models are also 6MP to 10MP (I don't think they had an 8MP DSLR).



The models I am talking about take 18-21MP stills. The popular "DSLR" type (I use this term because not all are truly DSLR) models are GH1, 5D, 7D, T2i

Not sure what models you're talking about, but 18-21MP => 2-3MP video is a larger difference, hence more aliasing. Going from 6-8MP => 2-3MP is much less


5. Shooting 24fps is not possible with any DSLR (I think 10fps is the maximum), because of memory and transfer restrictions - think of the fact that a DSLR should capture RAW, ie large amounts of data should be stored and transferred. This is why compression (AVCHD) was invented, right?


Yes, transfer and storage for RAW stills, but it's also limited by the processing for sampling to 2-3MP for video. A proper resize (e.g. bicubic, lanczos) instead of "line skipping" or "pixel binning" would require even more processing power.

Just think, If you could shoot 12MP stills from a 12MP sensor and have 12MP video, all in RAW, you should have very nice image with minimal aliasing right? That would be a Red One.$$



Why can an 8MP HD-camcorder show no sensible moiré and a 6MP DSLR (both CMOS, both Bayer-Pattern), employing the same DIVIC (processing power) but having a better optics, do? Why, why, why, I wonder why?


Still not sure what model you are talking about. The DSLR type models I am talking about were listed above, and shoot 18-21MP, not 6MP stills.

Anyways, I'm sure these explanations are just a gross oversimplification, but the fact is all the DSLR type models exhibit more aliasing and moire than "conventional" camcorders

[Soulhunter]

1. 80% (I think) concern Canon only, directly or indirectly (that is, the issue is generally described, but only Canon is given as example!!!).

Because 80% (I think) HD-VDSLRs out there are from Canon?


3b. The filming-DSLRs from Canon also have the DIVIC processor, and some models are also 6MP to 10MP (I don't think they had an 8MP DSLR).
Which ones are 6 or 10 MPix?
Its mainly a problem with the 550d (T2i), 7d and 5d mkII, and 1d mkIV, which are all close to 20MPix!


4. In EU, a photocamera cannot shot more than 30 minutes otherwise it will be considered a camcorder, thus an extra tax will be levered. This issue is not said in the shops, most of the time not even in the UserManuals, the sellers don't know or want to say.

Not really a problem as recording in 1080p will already stop after 12 minutes -> FAT32 4GB filesize limit! ;P


Why can an 8MP HD-camcorder show no sensible moiré and a 6MP DSLR (both CMOS, both Bayer-Pattern), employing the same DIVIC (processing power) but having a better optics, do? Why, why, why, I wonder why?
Because of the better optics!? :P


So the marketing said: ok guys, you'll have a DSLR which has the main purpose that of having good RAW pictures, occasionally you may use this for filming, but hey, if you want a good camcorder, please buy the camcorder! The same goes vice-versa for the photo shots of the camcorder.
Same with mobile phones and other stuff...
How many people would buy a mobile phone without camera, mp3 player, calculator, etc.?

[Ghitulescu]

Because 80% (I think) HD-VDSLRs out there are from Canon?
Globally there are 43% Canon to 25% Nikon :p, yes, Canon started the HDTV-movie-on-a-DSLR race (with a complete different purpose BTW) but now it's not the only player ...
Not really a problem as recording in 1080p will already stop after 12 minutes -> FAT32 4GB filesize limit! ;P
So does the camcorder too, it's the job for the software (and FW) to reassemble the files into a single recording.
Because of the better optics!? :P Moiré is not ALWAYS due to resolution, yet it plays a role.
Same with mobile phones and other stuff...
How many people would buy a mobile phone without camera, mp3 player, calculator, etc.?
Me, I don't like to have a bad camera on my cellphone that would cost me 30€ more, or an MP3 player whose licences raise again the price, and are you kidding about the calculator, right? Even on my fully QWERTZ keyboard (Nokia E71) I have problems in using the calculator... not to mention those having only 16 keys.

But this is offtopic.

[spiderman2k1]

Greetings,

anybody can determine what is this artifact, and what filter/tool is available to remove it?
Thanks in advance

http://img215.imageshack.us/img215/473/artifact.png

Aliasing and Moire problems

caprock filter

http://caprockdev.com/antimoire.htm

Read all the comments on vimeo the filter is not 100% perfect about 95% there.

7D Caprock 2.0 Anti Moire Filter, Aliasing Filter

http://vimeo.com/7523222

Rolling Shutter fix for After Effects.

http://www.thefoundry.co.uk/pkg_overview.aspx?ui=47C4AB50-4636-4326-87D1-FB380B2119EF

There is a Sony Vegas plugin from a company called New Blue

[scharfis_brain]

anyone thought of plain simple analogue composite chroma crosstalk also known as rainbows?