Why the image color bar doesn't contain certain color (Red, in particular)
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Sachin Motwani
on 21 Aug 2020
Edited: Sachin Motwani
on 22 Aug 2020
I used the following code in order to explore RGB images
X = imread ('parrot.jpg');
image(X);
colorbar
The output
Why doesn't the color bar contain red color even when the image does?
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Accepted Answer
Image Analyst
on 22 Aug 2020
If you want to see the 3-D color gamut, you can use colorcloud
colorcloud(rgbImage);
More Answers (1)
Walter Roberson
on 21 Aug 2020
Edited: Walter Roberson
on 22 Aug 2020
image() never changes the active colormap. (imshow() on the other hand changes the colormap for 2d arrays but not for rgb arrays.) You were displaying an rgb image so it had no need for a colormap.
colorbar never analyzes the contents of the display. colorbar only ever puts up a copy of the current colormap and associated numeric scale. In this case the default parula map was displayed.
See also https://www.mathworks.com/help/matlab/creating_plots/color-analysis-with-bivariate-histogram.html
Image Analyst has a better analysis tool but I cannot find it at the moment.
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