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Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

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Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#11

Post by dontreact »

btym wrote: post #9
dontreact wrote: post #7

Earlier quoted context omitted.

The script merely remaps the pixels in the input to new locations via PCA. I'm not 100% sure I know what you mean by "2 guys" or "color the writing".

The two guys on the page you just linked. The colored writing on the page you just linked.

Huh still confused somehow, sorry. This is the input https://github.com/ardila/paintingReorganize/blob/master/inp...

My script moves the pixels of that image around to get this output https://github.com/ardila/paintingReorganize/blob/master/out...

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#12

Post by minimaxir »

dontreact wrote: post #11
btym wrote: post #9

Earlier quoted context omitted.

The two guys on the page you just linked. The colored writing on the page you just linked.

Huh still confused somehow, sorry. This is the input https://github.com/ardila/paintingReorganize/blob/master/inp... My script moves the pixels of that image around to get this output https://github.com/ardila/paintingReorganize/blob/master/out...

They are asking how the generated gradient from the script was incorporated into the final image of the band promo.

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#13

Post by dontreact »

xbryanx wrote: post #10

The colors in that image seem super bright compared to the original. https://www.moma.org/collection/works/79971?locale=en

The output for that version of the painting looks similar. I just image searched for "kupka" and tried a few different results.

Result for your image: http://imgur.com/fp9i8BP

Do you think I should update the repo with this version?

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#15

Post by dontreact »

pavel_lishin wrote: post #14

I think there's a bug in there that flipped a few columns - but I actually really like the output better that way: http://imgur.com/RErXOF6

That is weird. It decides to flip a column by summing up the vector distances between the pixels in that column vs. the pixels in the previous column. I'm wondering if that since there is so much gray in the painting, this causes a large accumulation of error in gray vs. slightly different gray which outweighs the orange vs gray.

I do know that euclidean distance in RGB space is not that great a metric for perceptual similarity. Perhaps everything should be done in YUV instead? I will try tonight. Thanks.

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#17

Post by dontreact »

minimaxir wrote: post #12
dontreact wrote: post #11

Earlier quoted context omitted.

Huh still confused somehow, sorry. This is the input https://github.com/ardila/paintingReorganize/blob/master/inp... My script moves the pixels of that image around to get this output https://github.com/ardila/paintingReorganize/blob/master/out...

They are asking how the generated gradient from the script was incorporated into the final image of the band promo.

Ahhh. I tiled the image 4 times, remapped to polar coordinates, then did some color balancing.

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#18

Post by dontreact »

teaearlgraycold wrote: post #16

I'm curious where the noise is coming from, as some pixels appear to be out of place.

Yes: it seems to be for colors where they are similar to two or more other clusters of pixels. I imagine that these are just really hard to place without seeming too out of place? Also probably has to do with the column by column "greedy" approach that isn't really global.

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#19

Post by iverjo »

dontreact wrote: post #15
pavel_lishin wrote: post #14

I think there's a bug in there that flipped a few columns - but I actually really like the output better that way: http://imgur.com/RErXOF6

That is weird. It decides to flip a column by summing up the vector distances between the pixels in that column vs. the pixels in the previous column. I'm wondering if that since there is so much gray in the painting, this causes a large accumulation of error in gray vs. slightly different gray which outweighs the orange vs gray. I do know that euclidean distance in RGB space is not that great a metric for perceptual…

I recommend you to try the LAB color space and to use delta E 94 [1] for computing distances between colors in the color space

[1] https://en.wikipedia.org/wiki/Color_difference#CIE94

Re: Show HN: Reorganize pixels of a painting into a smooth color palette using PCA

#20

Post by dontreact »

minimaxir wrote: post #12
dontreact wrote: post #11

Earlier quoted context omitted.

Huh still confused somehow, sorry. This is the input https://github.com/ardila/paintingReorganize/blob/master/inp... My script moves the pixels of that image around to get this output https://github.com/ardila/paintingReorganize/blob/master/out...

They are asking how the generated gradient from the script was incorporated into the final image of the band promo.

The flyer is in the facebook event not the band page. The cover photo for the album was a completely separate project :)
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