How do I specify the color data as numeric or logical value?

I'm currently using a code from github for fringe analysis. It works perfectly for the example image but when Im using .tif images with an 'indexed' colormap and RGB-palette I always get this error:

Error using image

Complex values are not supported. Specify the color data as numeric or logical values.

Error in imagesc (line 52)

hh = image(varargin{:}, 'CDataMapping', 'scaled');

Error in example (line 61)

imagesc(1 ./ freq);

How do I need to specify the colordata?

Heres the part from the code:

subplot(2, 2, 1);
im.resize(scale).plot();
title('test image');

subplot(2, 2, 2);
imagesc(1 ./ freq);
axis image;
colorbar;
set(gca, 'XTick', [], 'YTick', []);
title('apparent spacing, nm');

Regards,

M

Answer 1

[DGM]

I'm going to have to assume that freq or 1./freq are complex-valued. The arguments to image()/imagesc() need to be real-valued. How you choose to reduce the complex values depends on what your intentions are. You could look at only the components of the data

real(1./freq)

or

imag(1./freq)

or you could look at the magnitude

abs(1./freq)