Subject:
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Re: Mosaic programs
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Newsgroups:
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lugnet.build.mosaic
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Date:
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Tue, 15 Feb 2005 18:22:21 GMT
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Viewed:
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5525 times
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In lugnet.build.mosaic, Maarten Steurbaut wrote:
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Now we have something to compare:
On the left the original image.
In the middle my result with black, white, yellow, red and blue.
On the right Corey’s result with the same colours.
I don’t make artistic mosaics, they’re purely mathematical. I use the
Floyd-Steinberg dithering algorythm. Bob uses it too (plus a few variations
of this algorythm).
So Corey: do you use an existing algorythm (like
iterative algorythms, that I can’t program unfortunately), or have you
invented something completely new?
The first thing I noticed about your
image: the area bottom-right is entirely white, while this area on the
original image isn’t. With my FS-algorythm I expected pixels of a different
colour in this area (I didn’t remove them manually to make comparison
possible). What did you do to get this area white? Do you use some kind of
“less dithering”-method?
In my mosaics there are many 1x1 elements, much
more than in yours. Is this intended or just a coincidence? I’m asking this
because I also make ministeck mosaics where 1x1 elements are very rare. I
wrote an extra module to avoid as many 1x1 elements as possible, but I’m not
completely happy about it. All suggestions are welcome.
Maybe you can lift a
corner of your veil?
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I’d say it looks like the image on the right was contrast enhanced
before the dithering was applied. Stand back and squint at the
images to see the change in contrast. The light colors are all
clearly whiter. You can also see some color banding beneath
the dither on the top right of the forehead, which is what
you’d expect if some sort of histogram filter was applied to
stretch the range of colors in the image before dithering. And
although I don’t see evidence of it here, you might want to apply
an edge enhancement filter before dithering to make the resulting
mosaic look crisper.
Have fun,
Don
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Message is in Reply To:
 | | Mosaic programs
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| Now we have something to compare: (URL) On the left the original image. In the middle my result with black, white, yellow, red and blue. On the right Corey's result with the same colours. I don't make artistic mosaics, they're purely mathematical. I (...) (20 years ago, 15-Feb-05, to lugnet.build.mosaic, FTX)
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