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Re: AppleShop Project - Euclidian Distance and Nearest Color in DHGR - Historical Info if Any?

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"Dagen Brock" <DagenBrock@gmail.com> wrote:
> I just came here to say that I based some of my IIgs image conversion 
> experiments on CIEDE2000.   I guess you could say it's Euclidian Distance 
> within a defined color space and perceptual adjustments.

That's precisely it.

http://bisqwit.iki.fi/story/howto/dither/jy/

>The only reason I bring it up is that there is a difference between a 
>simple algorithmic distance, and human eye perceptual difference 
>(psychovisual).

My last couple of converters apply Euclidian Distance and the Pychovisual 
Model. I am currently attempting to develop a simpler horizontal alternating 
ordered dithering algorithm.

I have an error diffusion filter in place but I am not convinced that 
smearing the colors diagonally is as effective for DHGR and HGR conversions 
of complex images as smearing the colors in the xaxis only like in a 2 pixel 
merge. But a merge dulls the colors and somewhat defeats the PsychoVisual 
model.

My suspicion is that alternating a horizontal dither between line pairs 
using a simple pair of thresholds for pixel pairs, one  based on the kegs 
palette that we both use with the safe colors, and the other being a 
midpoint threshold variation, might work well enough.

I hope to try this later today before advancing to the other methods in 
Joel's paper.

Bill 

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AppleShop Project - Euclidian Distance and Nearest Color in DHGR - Historical Info if Any? "Bill Buckels" <bbuckels@mts.net> - 2014-06-04 08:39 -0500
  Re: AppleShop Project - Euclidian Distance and Nearest Color in DHGR - Historical Info if Any? "Bill Buckels" <bbuckels@mts.net> - 2014-06-10 05:14 -0500
    Re: AppleShop Project - Euclidian Distance and Nearest Color in DHGR - Historical Info if Any? Dagen Brock <DagenBrock@gmail.com> - 2014-06-24 12:48 -0700
      Re: AppleShop Project - Euclidian Distance and Nearest Color in DHGR - Historical Info if Any? "Bill Buckels" <bbuckels@mts.net> - 2014-08-07 07:35 -0500

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