D90 Stair-Stepping Removal

[Halsu]

Interesting -

...i'll be getting a D90 soon (mainly for stills though), so this inspired me to make my own version, using a displacement map. It has only one layer plus one tga image to deal with, instead of those sliced layers. My method looks more or less as good (as far as i can tell), but probably renders quite a bit faster (didn't test the original version).

Here's the AEP (v 7.0), in case you're interested ;-)

http://eki.pp.fi/digivideo/D90/D90FIX.zip

The same .tga file should work pretty much universally, with any app that has displacement map functionality. In AE, setting of 0.3 in vertical displacement gave decent results - this will vary between applications, of course. I tried with Vegas - it works, so i added the .veg file to the zip.

[Rubbersquare]

is it just me, or is this a way easier solution?
combine this displacement map with the noise thing from neatvideo?
seems like you guys (lee & matt, too) would create the nikon d91x (whatever, when they "fix" their issues."
roll in an anti-jello filter and she-bang - awesomeness for <$2000 !!!

[buildyo]

Cool, keep the ideas coming. Of course this is a much easier method but as I'm in the After Effects Club since yesterday I just tried it and I find while it looks v-e-e-e-ry good it doesn't look quite as good as Dr. Wilsons cure. As you can see there are still some tiny stairsteps. But maybe thats not important on real world images (especially when you downscale to 360p). Halsu, is it possible to fine tune the displacement map to get the same smooth edges as in the right most image?



How did you make the map? I mean the tga file. I noticed that you used an uniform 8 pixel distance and that the black line isn't always black. What happens when the displacement map pushes pixels on top of each other? Become they interpolated?

[Lee Wilson]

Originally Posted by Halsu

Interesting -

...i'll be getting a D90 soon (mainly for stills though), so this inspired me to make my own version, using a displacement map. It has only one layer plus one tga image to deal with, instead of those sliced layers. My method looks more or less as good (as far as i can tell), but probably renders quite a bit faster (didn't test the original version).

Here's the AEP (v 7.0), in case you're interested ;-)

http://eki.pp.fi/digivideo/D90/D90FIX.zip

The same .tga file should work pretty much universally, with any app that has displacement map functionality. In AE, setting of 0.3 in vertical displacement gave decent results - this will vary between applications, of course. I tried with Vegas - it works, so i added the .veg file to the zip.

Brilliant !

It doesn't give quite a good result as actually going in there and chopping every single step out - but it is 80-90% as good and for a whole lot less effort and more transferable to other software.

Genius !

[taubkin]

What bugs me about all this, is: Why couldn't nikon have done this! I mean, is this really the easiest way? Get crappy video files and suffer to bring them back to life in post? Couldn't some of this (noise reduction, line interpolation) be done in hardware by the camera? Jeez...

But nice touch with the displacement map!

[Halsu]

Originally Posted by buildyo

How did you make the map? I mean the tga file. I noticed that you used an uniform 8 pixel distance and that the black line isn't always black.

I made a 9 pixel tall gradient strip in photoshop using the standard gradient tool, then copied that in after effects, eyeballing it so that it matched the jaggies. When i tried this with the AE displacement plugin, it resulted in pretty weird bulges on each strip.

I applied a gamma correction to the displacement map, again eyeballing the correction that gave straight lines - the resulting gamma was 2.2, i recall, which probably has much to do with video's default 2.22 gamma.

The places where the black lines show as gray are places where the strips weren't exactly 9 pixels apart - i didn't make a separate 8 pixel wide strip, positioning the 9 pixel strip half pixel off looked OK with my eyeball method... true 8 pixel strips might have been better, but i was a bit tired at the time - it was 2 am local time ;-)

The results most probably could be further improved by adjusting the displacement map, i might have a go at it some time later.

What happens when the displacement map pushes pixels on top of each other? Become they interpolated?

My aim was basically to scale each 9 pixel strip vertically (black areas in the disp map push pixels up, white areas push them down). I think the pixels that get pushed together more or less disappear, they get scaled so small while being pushed from two sides... but i am not sure of this really, it's all just guessing ;-).

[Halsu]

Originally Posted by taubkin

What bugs me about all this, is: Why couldn't nikon have done this! I mean, is this really the easiest way? Get crappy video files and suffer to bring them back to life in post? Couldn't some of this (noise reduction, line interpolation) be done in hardware by the camera? Jeez...

But nice touch with the displacement map!

I'm pretty sure it all boils down to processing power, which boils down to price... If my dual core laptop's processors can't do it in real time, no wonder if a camera's built in one cant.

[Halsu]

While playing around with this pixel displacement stuff, i added a warp sharp composition to the project - it pushes the pixels towards image feature edges, thus sharpening them without affecting edge contrast or adding halos. Depending on the content, it works pretty well...

http://eki.pp.fi/digivideo/D90/D90FIX-v004.zip

[buildyo]

Halsu, you did a great job eyeballing this!
I wrote an Illustrator script to fill the individual 7px, 8px and 9px slices with gray values according to your procedure pasted it into photoshop and saved it as a tif file. I think it's now closer to the LEEFIX but I'm biased :-) It would help if we could shift the map in finer steps than 0.1.



Right-click the link below to download my displacement map:
http://www.dvxuser6.com/uploaded/39976/1224345291.tif

[Halsu]

Excellent!!