MATLAB Answers


How do I create an 2D intensity map from a PNG image?

From an infrared microscope with limited software I'm able to obtain an intensity map with a color scale bar including corresponding values. The limited software only provides this map in PNG format. I'm able to read the image into MatLab but I haven't got the know-how to generate a visually similar intensity plot with its corresponding color scale bar (with its values). Could anybody help me on my way with the following image?

Any help would be greatly appreciated.

  1 Comment

Is the question about how to examine a PNG image to determine the mapping between colors and intensity values, so that given intensity values you can reproduce the appropriate output? So this is about "reverse engineering" a colorbar ?

If so then there have been several Questions about that.

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2 Answers

Answer by Chad Greene
on 25 Sep 2017
 Accepted Answer

That looks like your data are on a grid about 11x11 or so, and linearly interpolated between data points. To plot an 11x11 matrix, let's call it M, I think pcolor is the command you're looking for.

shading interp 

And to set the color axis values use caxis:

caxis([1.180 2.273]) 

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Answer by Image Analyst
on 25 Sep 2017

See similar problem I did for a thermal image. The attached program can do what you want if you adapt it.


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