sw_multicolor

overlays monochrome maps into a single RGB map

Syntax

cmat = sw_multicolor(vmat, cmap, clim, {ncol}, {flipud})

Description

cmat = sw_multicolor(vmat, cmap, clim, {ncol}, {flipud}) takes 2D matrices and overlays them and generating RGB color additively from the user defined colors correspond to each map. The function is used in sw_plotspec when multiple correlation functions are overlayed on the same plot.

Examples

In this example we create two intensity maps stored in the square matrices A and B (linearly changing intensity along $x$ and $y$ axes respectively, intensity ranging between -2 and 2). We plot these intensity maps by converting them to RGB colors using the inline function rgbMap and the Matlab built-in function image. We use sw_multicolor function to additively combine A and B and providing a color saturation value of 1 (and lowest value of -1). It is clearly visible on the resulting plot of C that it is white where both A and B has zero value (or below the lowest color value of -1) and it is red+green where both A and B are saturated.

rgbMap  = @(mat,RGB,clim)bsxfun(@plus,ones(1,1,3),bsxfun(@times,(mat-clim(1))/diff(clim),permute(RGB(:)-1,[2 3 1])));
 
red   = [1;0;0];
green = [0;1;0];
 
[A,B] = ndgrid(linspace(-2,2,501),linspace(-2,2,501));
C = sw_multicolor(cat(3,A,B),[red green],[-1 1]);
 
figure
 
subplot(1,3,1)
image(rgbMap(A,red,[-1 1]))
title A
 
subplot(1,3,2)
image(rgbMap(B,green,[-1 1]))
title B
 
subplot(1,3,3)
image(C)
title C=A+B

Input Arguments

vMat

Matrix that contains the input 2D intensity data, dimensions are $[d_1\times d_2\times n_{plot}]$ , where each intensity map has a dimension of $[d_1\times d_2]$ .

cMap

Defines the color map that maps intensity values within the cLim limits to colors, can be the following types:

matrix Matrix of RGB colors, where each column corresponds to an RGB triplet. The dimension of the matrix is $[3\times n_{plot}]$ and the $i$ th color corresponds to the color of the $i$ th intensity map in the vMat stack.
cell Cell of $n_{plot}$ colormap functions. For example {@copper @gray}.

cLim

Defines the maximum and minimum intensity values that the given color map will span. Values in vMat smaller than the minimum and larger than the maximum will be shown with the minimum and maximum color in the colormap respectively. cLim is a row vector with 2 elements..

nCol

Number of colors in the colormap. Optional, default value is 100.

flipud

If true the given colormaps are inverted. Optional, default value is false.

Output Arguments

cMat: Matrix that contains the RGB image, with dimensions of $[d_1\times d_2\times 3]$ . The image can be shown using the image built-in Matlab command.