Perceptually improved colormaps

5 perceptual colormaps with rainbow-like colors and 1 with heat colors

Description

PMKMP Returns perceptually balanced colormaps
   PMKMP(N,SCHEME) returns an Nx3 colormap.
   usage: map=pmkmp(n,scheme);

Example: 128-color rainbow with cubic-law luminance (default)
       % load mandrill;
       % imagesc(X);
       % colormap(pmkmp(128));
       % colorbar;

JUSTIFICATION: rainbow, or spectrum color schemes are considered a poor choice for scientific data display by many in the scientific community (see for example reference 1 and 2 in the help) in that they introduce artefacts that mislead the viewer. "The rainbow color map appears as if it is separated into bands of almost constant hue, with sharp transitions between hues. Viewers perceive these sharp transitions as sharp transitions in the data, even when this is not the casein how regularly spaced (interval) data are displayed (quoted from reference 1). This submission is intended to share the results of my efforts to create more perceptually balanced color maps. Please see output arguments section for descriptions.

See files examples.m, examples1.m, and example2.m and associated figures for more examples
See files MakeLabPlotUsingColorspace.m and CompareLabPlotsUsingColorspace.m for some demonstrations.

See also: JET, HSV, GRAY, HOT, COOL, BONE, COPPER, PINK, FLAG, PRISM, COLORMAP, RGBPLOT
 
Extensive reference list and list of other FEX submissions of interest included in the help

Please visit my blog to read about the background research:
http://mycarta.wordpress.com/2012/05/29/the-rainbow-is-dead-long-live-the-rainbow-series-outline/

Author: Matteo Niccoli
e-mail address: [e-mail]
Release: 2.0
Release date: March 2012

Acknowledgements

Light Bartlein Color Maps, Cold Colormap, Colorspace Transformations, Spectral And Xyz Color Functions, Cline, Lab Color Scale, Shaded Pseudo Color, and Make Color Map inspired this file.

This file inspired Colormapline Color Changing 2 D Or 3 D Line.

• MATLAB release: MATLAB 7.4 (R2007a)

[Matteo Niccoli]

Correct link:
http://mycarta.wordpress.com/2012/05/29/the-rainbow-is-dead-long-live-the-rainbow-series-outline/

[Matteo Niccoli]

All research to be published here:
http://mycarta.wordpress.com/2012/05/30/the-rainbow-is-dead-long-live-the-rainbow-series-outline/

[Matteo Niccoli]

Colin, thank you for your positive comments. I just got back after a trip and saw your post. I will look into improving/clarifying use of examples.m asap. I may wait a bit to implement an updated as I have some add-ons modifications I am working on.

[Colin]

Really interesting discussion/solution of a topic I hadn't given enough thought to.

Colin

p.s. It might be worth adding:

set(0,'defaultfigureunits','pixels')

to the start of "examples.m". It took me a while to figure out why no figures were visible.

Alternatively you could consider using:

set(fign,'OuterPosition',[0.25 0.25 0.5 0.5],'units','normalized');

[Colin]

 

[Petros Mpogiatzis]

indeed, perceptually better!