How to plot colorbar as seperate image?

Hi, I would like to plot the colorbar of an image not next to my image, but in a seperate figur window. Therefore the colorbar should even be plotted in the size of an image.

I am looking for something like this:

min_val=min(example_img(:)); 
max_val=max(example_img(:));
figure(1),
imshow(example_img,[min_val max_val]); %show the image, but without colorbar
h=colorbar 
%do something to prevent showing the colorbar in figure(1)
colorbar_img=get_colorbar_img(h) %do something to get an image that shows the %colorbar and has the same size as example_img 
figure(2)
imshow(colorbar)

thanks for you help!

Answer 1

[TADA]

I assume your image is grayscale, right?

If I understand you correctly:

min_val=min(example_img(:)); 
max_val=max(example_img(:));
figure(1);
imshow(example_img, [min_val, max_val]);

% setting the color map of the image to whatever we want
% I chose parula here but you can use whatever colormap
set(gca, 'colormap', parula);

% this generates a single column colorbar the same height as your image
% mapping colors to your image values between the calculated minimum and maximum
% because you wanted it as an image i translated it back to uint8
colorColumn = uint8(linspace(double(min_val), double(max_val), size(example_img, 1))');

% this will stretch the color-bar to the same width as your image
colorBarIm = repmat(colorColumn, 1, size(example_img, 2));

% this will display the color bar image on a second figure
figure(2);
imshow(colorBarIm);

% flip the axis view point because images are shown from top to bottom 
% but colorbars are displayed bottom-up
view(180, 90);

% setting the color map of the colorbar image to match the one
% we set for the actual image
set(gca, 'colormap', parula);

% You probably also want to show the values corresponding to the colormap
axis on;
% remove the x tick marks because they are usually meaningless ona  colorbar
xticks([]); 

[David Weller]

Wow, thanks a lot for helping me out so fast :)