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So, I go to install GMIC for Gimp via the package manager and landed myself upon the demo program. I have discovered things such as Hough transform and color quantization. So, I get the number of colors on the bottom bar, I understand what it is doing, but I do not get the cube in the middle, mainly why it's 3D or that it has other shapes inside of it (other than the dots for the colors chosen). Basically, I want to know the purpose of this cube, such as why is it a cube, or why is it 3D.

Original RGB Quantization Picture!

Edit: I hope this is a better picture. Turns out the image is different too!

I hope this is a better picture. Turns out the image is different too!

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  • $\begingroup$ Most Color Quantization algorithms do clustering in the RGB cube (splitting the space of colors in big significant chunks). Try to search for NeuQuant, Xiaolin Wu quantization algorithms for more details. $\endgroup$ – wip Dec 21 '16 at 16:02
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The cube looks like just an RGB cube, i.e. X,Y,Z map to R,G,B. Since there are 3 color channels, the 3D cube is a convenient way to visualize the space of all possible RGB colors. However, I don't know what the pie-wedge-looking shape outlined inside the cube is.

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  • $\begingroup$ It also seems like maybe the size of the spheres inside the cube correspond to the number of pixels of that color in the image. So it's a 3D histogram, basically. Is the pie wedge maybe the CIE XYZ "shark fin"? $\endgroup$ – user1118321 Nov 30 '16 at 21:11
  • $\begingroup$ @user1118321 I can't tell from the image whether the size of the circles inside the cube correspond to sphere size (with some unspecified meaning) or just to proximity to the camera (giving an idea of 3 dimensional position in the cube). $\endgroup$ – trichoplax Nov 30 '16 at 21:32
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    $\begingroup$ The white spheres seem to be the quantized colors in the 3D histogram. There are total of 24 of them in the image, i.e. the number of quantized colors. $\endgroup$ – JarkkoL Dec 1 '16 at 14:19

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