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Kurosu · 1st October 2002, 02:58

@High Speed Dubb

Thanks for the very interesting link, and sorry for the late reply. As your idea even more underlines, I fear that there isn't a good method: I'm considering 16x16 blocks (because videos I had were only affected on entities of that size), you're dealing with PAL signal properties. I'm not familiar with those considerations, but I'll look more closely: maybe a good idea will pop up

Concerning your idea:
- to detect possible crosstalk, I count how many pixels are likely to be crosstalks. Looking at the blocks in UV planes clearly show high activity. I simply count the number of pixels which derivative (calculed by Robert's filters) is higher than a certain threshold, then consider a threshold number of pixels for which the block is considered as to be temporally smoothed (the more sample the better, if no ghosting artifacts

)
- your idea would likely give a more precise result by only affecting some pixels, not the whole 16x16 block. However, the only material I have is from MPEG source. Maybe people from the capture and TV encoding forums could provide us with more general "rainbow artifact" (not shadow ^^

. As a result, I dunno. All the matter involved is "when can we consider that a pixel is a crosstalk". My MPEG source show a block basis:
Original image
Y Plane
U Plane
- I'm not convinced by the the spatial smooth. I put some sort of spatial smoothers (blur, then filling with average on parts of the 16x16 block) but their result are awful. Just imagine a logo or something of the like with a lot of chroma activity (high frequencies I mean), detected as crosstalk. Smooth it. Yuk...

My idea is to expect that the crosstalk is due to a random signal added to the UV planes. Then, by temporal smoothing it, you will reduce it. The next idea is to use local information, like Y values, to do a sort of deconvolution to remove the aliasing due to Y signal. Fact is that I dunno if people would be interested in a very good filter but slow as hell. Anyway the doc you pointed out will certainly be really helpfull. I tried to find such a doc. Moreover, i've bookmarked the whole site for "theory basis"

Btw, I had no answer like effective/uneffective, bugged, hard to setup and the like on my lattest build... I think I'll do for my own sake some additionnal developments, but is there anyone that would like improvements? Or should I crosspost to the capture forum ?

1st October 2002, 02:58	#28 \| Link
Kurosu Registered User Join Date: Sep 2002 Location: France Posts: 432	@High Speed Dubb Thanks for the very interesting link, and sorry for the late reply. As your idea even more underlines, I fear that there isn't a good method: I'm considering 16x16 blocks (because videos I had were only affected on entities of that size), you're dealing with PAL signal properties. I'm not familiar with those considerations, but I'll look more closely: maybe a good idea will pop up Concerning your idea: - to detect possible crosstalk, I count how many pixels are likely to be crosstalks. Looking at the blocks in UV planes clearly show high activity. I simply count the number of pixels which derivative (calculed by Robert's filters) is higher than a certain threshold, then consider a threshold number of pixels for which the block is considered as to be temporally smoothed (the more sample the better, if no ghosting artifacts ) - your idea would likely give a more precise result by only affecting some pixels, not the whole 16x16 block. However, the only material I have is from MPEG source. Maybe people from the capture and TV encoding forums could provide us with more general "rainbow artifact" (not shadow ^^. As a result, I dunno. All the matter involved is "when can we consider that a pixel is a crosstalk". My MPEG source show a block basis: Original image Y Plane U Plane - I'm not convinced by the the spatial smooth. I put some sort of spatial smoothers (blur, then filling with average on parts of the 16x16 block) but their result are awful. Just imagine a logo or something of the like with a lot of chroma activity (high frequencies I mean), detected as crosstalk. Smooth it. Yuk... My idea is to expect that the crosstalk is due to a random signal added to the UV planes. Then, by temporal smoothing it, you will reduce it. The next idea is to use local information, like Y values, to do a sort of deconvolution to remove the aliasing due to Y signal. Fact is that I dunno if people would be interested in a very good filter but slow as hell. Anyway the doc you pointed out will certainly be really helpfull. I tried to find such a doc. Moreover, i've bookmarked the whole site for "theory basis" Btw, I had no answer like effective/uneffective, bugged, hard to setup and the like on my lattest build... I think I'll do for my own sake some additionnal developments, but is there anyone that would like improvements? Or should I crosspost to the capture forum ?