Find image pixels linked to a specific color in its colormap

Hi. I need to find which pixels in an image are linked to a specific colour of its colormap. I have one RGBA image that, when importing with imread(), I get the image (m-by-n matrix) and its colourmap (r-by-3). I know I can do it using find() function (like in the code bellow) but I would like to know if there is another way? Maybe a manual way that I can find the pixels linked to that specific colour/range of colours in the map?

[I,map] = imread('image.png'); % 'I' is represented in uint8 and 'map' in double
find(I==1) %Considering that the pixels I want to find are the ones represented by the colour (1,1,1) in the colormap

Thanks!

Answer 1

[Leonardo Alves]

So, after a lot of searching and reading I found a way of how to find the pixels linked to every colour of colormap. Based on that I can do a manual search for a specific colour.

Solution:

[I,map] = imread('image.png'); % 'I' is represented in uint8 and 'map' in double
figure
imshow(A,map); %Plot the image and its colormap
colorbar; %Show the colormap in the plot
ax = gca;
spectData = ax.Children.CData; %Generate a matrix (m-by-n) with the color in each pixel

Based on that I can now use loops or any other function instead of find() to find the pixels required based on its colour.