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Maximally Distinct Color Generator

バージョン 2.4.1 (457 KB) 作成者: Stephen23
Generate maximally distinct colors in an RGB colormap.

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更新 2022/7/7

ライセンスの表示

MAXDISTCOLOR generates an RGB colormap of maximally-distinct colors.
MAXDISTCOLOR has two required input arguments:
  1. the required number of colors.
  2. a function handle that converts from sRGB to some kind of uniform colorspace (e.g. CIELab, OKLab, DIN99, DIN99o, OSA-UCS, CAM02-LCD, CAM02-UCS, CAM16-LCD, CAM16-UCS, etc.).
Optional input arguments allow the user to:
  • Limit the lightness range.
  • Limit the chroma range.
  • Provide a colormap of colors to be excluded (e.g. background colors).
  • Provide a colormap of colors to be included (e.g. company colorscheme).
  • Specify the RGB bit depth (e.g. 8 bits per channel, TrueColor).
  • Sort the colormap (e.g. by hue, chroma, lightness, farthest colors, etc.).
See the Examples tab (HTML documentation) for explanations of the required and optional input arguments.
Warning
Requesting many colors from a large gamut can require hours/days/... of processing. Some option combinations are not tractable.
Examples
>> N = 5;
>> fun = @sRGB_to_OKLab;
>> rgb = maxdistcolor(N,fun)
rgb =
0 0 0.8095
1.0000 0.3858 0
0.8254 0 1.0000
0.4286 0 0.0159
0 0.8189 0
>> axes('ColorOrder',rgb, 'NextPlot','replacechildren')
>> X = linspace(0,pi*3,1000);
>> Y = bsxfun(@(x,n)n*sin(x+2*n*pi/N), X(:), 1:N);
>> plot(X,Y, 'linewidth',4)
>> maxdistcolor(5,fun, 'exc',[0,0,0]) % Exclude black (e.g. background).
ans =
1.0000 1.0000 1.0000
0 0 1.0000
0 0.6772 0
1.0000 0.1969 1.0000
0.5238 0 0.0635
>> maxdistcolor(5,fun, 'inc',[1,0,1]) % Include magenta.
ans =
1.0000 0 1.0000 % <- magenta!
0 0.8583 0
0.1111 0 1.0000
0 0.2677 0
0.8254 0.3858 0
>> [rgb,Lab] = maxdistcolor(6,@sRGB_to_CIELab, 'Lmin',0.5, 'Lmax',0.7)
rgb =
0.7619 0 1.0000
1.0000 0 0
0 0.7795 0
0 0.5591 1.0000
0.8254 0.6457 0.0794
0.8254 0.2835 0.5397
Lab =
50.3665 89.7885 -77.4167
53.2329 80.1093 67.2201
69.9972 -71.4464 68.9566
58.7262 9.8285 -64.4614
69.8987 5.1700 70.3789
52.1378 59.8754 -6.6658
Motivation
The development of MAXDISTCOLOR was prompted by:
  1. Existing "distinct color" generators use inadequate colorspaces and/or algorithms, leading to suboptimal color distinctiveness.
  2. The realization that 64 bit PCs with >8 GB of RAM can operate on the entire 16 million colors of 24 bit TrueColor, allowing for neat and simple vectorized MATLAB code.
These two motivations are closely linked to two non-trivial tasks that have to be solved in order to generate maximally-distinct colors:
  1. An algorithm to find the best color combination requires finding the global optimum, a task which grows exponentially with the number of requested colors and with the color gamut size. In MAXDISTCOLOR I use repeated application of a simple greedy algorithm to find the maximally-distinct colors: the repeated greedy algorithm is not particularly fast and is not a general solution for finding a global optimum, but luckily it gives good results for the regularly sampled RGB cube. Note that this algorithm contains no random numbers: it is entirely deterministic and repeatable.
  2. Defining a true uniform colorspace: the venerable CIELab (used by most existing tools I could find) is not really very uniform, particularly around the blues/greens. For MAXDISTCOLOR I recommend CAM02-LCD or CAM02-UCS or CAM16-LCD or CAM16-UCS or OKLab or OSA-UCS, all of which provide a more accurate measure of the color distance.

引用

Stephen23 (2022). Maximally Distinct Color Generator (https://www.mathworks.com/matlabcentral/fileexchange/70215-maximally-distinct-color-generator), MATLAB Central File Exchange. 取得済み .

MATLAB リリースの互換性
作成: R2010b
R2009b 以降と互換性あり
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