CGTalk - Soften only the small jagged areas

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EricChadwick

04-28-2004, 07:45 PM

Is there a filter lurking in PS7 somewhere that will blur only small chunks of pixels that are aliased, and leave larger aliased chunks as well as smooth areas completely untouched?

I've been experimenting with ways to create a height map out of a photo texture, by using Smart Blur to accentuate cracks and such while softening the fine noisiness out of the image. Then I fade the blurred layer back on top of the unblurred one, to pull back in a little of the original noisiness.

Anyhow, Smart Blur tends to leave little 4x4 or so bits of aliased pixel chunks, which I'd like to remove easily, without affecting the larger sharp-edged features I want to keep.

One way I tried was to scale up 200%, then back down 50%. Works somewhat, not the best though, had to do it a couple times, tends to blur the whole image too.

Anyone have some tips?

singularity2006

05-03-2004, 07:47 AM

I wish there was an easier way for what you are talking about. I've asked around here and there and in general, there is no process easily describable to do this - just a lot of patience. I hear crazy things about how some of these super crazy photo correction guys work in small 50x50 px areas (and sometimes smaller) to correct the image by the pixel until the whole thing is done. But an image has to be dang screwed up for that kind of fine tuning I think. Having a good high resolution file to start with makes it easy since you can do a lot of great custom selections using the magic wand tool and proceed to edit from there.

Gibbz

05-05-2004, 05:52 AM

if it was only a small amount u could use the blur tool?

Stroker

05-05-2004, 11:15 AM

Try using Find Edges as a mask for blurring.

EricChadwick

05-05-2004, 01:29 PM

singularity2006 that sounds like no fun.

Thanks Stroker, that might work, although it'll probably grab all hard edges, not just the small-radius ones.

Unfortunately Gibbz the pixel chunks are all over the place.

Oh well, thought it might be something easy I'd overlooked. Maybe one of those hundred or so filters tucked up in there.

Stroker

05-05-2004, 02:05 PM

You mentioned Smart Blur.
Have you tried it with Mode: Edges Only for a mask?
Can't say for sure because it might be backwards.

erikals

05-05-2004, 11:45 PM

Sort of like this?

EricChadwick

05-06-2004, 12:22 AM

Here's what I'm doing, top to bottom. Trying to end up with some nice cracks and variation from the original, but without the huge amount of noise that pure grayscale gives me.

http://www.ericchadwick.com/examples/images/dirt_bump.jpg

It's almost there, but just not quite the quality I'm shooting for. I lose all the nice hard indentations. I'm looking for a process I can make into an Action script, to do on a bunch of images.

Stroker

05-06-2004, 03:08 AM

Maybe try tossing High Pass into the mix?

The Power of the High Pass Filter (http://www.3dgate.com/techniques/2001/010625/0625hajba.html)

I think that will get you there, but I'm not entirely sure because I don't know a whole lot about these things.

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