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-   -   How to hide a stuck or dead pixel? (

Spotty 02-10-2019 05:51 AM

How to hide a stuck or dead pixel?
There is a faulty pixel in the camera that was stuck to permanent whiteish.
Strangely it is only noticeable in videos that were taken under low light conditions.
Since the camera has some stabilisation built in, you can see what the stabilisation is doing by watching the white dot move around a little.
I have tried using a logo remover, which did work to some degree, but due to the cameras stablisation moving the dot around I needed to make the region much larger than the dot, and so now for example if someones eye gets in that region, their eye disappears, and that looks really wierd.
Ideally I need a filter that tracks the white dot and fills it in from the surrounding colors.
Any suggestions?

dpalomaki 02-10-2019 06:43 AM

In low light with AGC on camcorders will amplify the signal read off the CCD/CMOS and that will make any hot pixel even brighter. If surrounding pixels are dark it stands out more.

With at least some camcorders factory service can mask bad pixels so they are not seen.

You might be able to use a capable NLE to mask the area of concern, and use luma key within that mask area to replace the hot pixel with a nearby pixel from a copy of the video placed on a lower track and shifted slightly.

Spotty 02-10-2019 07:15 AM

That sounds like a good solution, do you know what filters in Virtualdub/Avisynth could do this?

lordsmurf 02-10-2019 07:38 AM

There is very likely a way to clone a neighbor pixel over the bad pixel. This would be superior to masking.

I don't know the Avisynth script needed off-hand, and a sample clip would be required. Either sanlyn here at dFAQ knows, or jagabo, poisondeathray or manono over at VH. I know I've seen scripts from jagabo, to accomplish similar (and more complex) tasks.

Start by posting a sample clip here. I'll give one of them a nudge, see if they can give you some scripting help. :)

... and this would be something good to know, if I ever have the need.

Spotty 02-11-2019 05:04 AM

1 Attachment(s)
Here's a clip with both light and dark image behind the pixel.

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