how to create a histogram of R,G,B

i have three component R(0-255),G(0-255),B(0-255) i draw 3 different histograms of each component of 8 bins but i need one 2-D histogram of 8 bins.

[Jan]

What is your question? How do you want to transform the 3 components to a 2D space?

Answer 1

[Youssef Khmou]

hi,

You mean putting them on one figure, with each component its corresponding color :

I=imread('autumn.tif');
R=imhist(I(:,:,1));
G=imhist(I(:,:,2));
B=imhist(I(:,:,3));
figure, plot(R,'r')
hold on, plot(G,'g')
plot(B,'b'), legend(' Red channel','Green channel','Blue channel');
hold off,

Answer 2

[Image Analyst]

What does this mean? Do you either want (1) histograms of each color channel (either on the same plot or on 3 separate plots), or (2) a scatterplot of the 3D color gamut? I have demos of each of those, just say what you want.

[preet]

1 histogram of each color channel on same plot

[Image Analyst]

See attached demo.

[Sumaiya Ali]

how can I get the x and y axis numbers for images when I use imshow() like in your output?

[Image Analyst]

@Sumaiya Ali what does "get" mean to you? You can try xticks(), xticklabels(), axis('on', 'image'), or other things. You have not explained very precisely what you want.

Answer 3

[Chinnu]

I=imread('autumn.tif'); 
R=imhist(I(:,:,1)); 
G=imhist(I(:,:,2)); 
B=imhist(I(:,:,3)); 
figure
plot(R,'r') 
hold on, 
plot(G,'g') 
plot(B,'b')
legend(' Red channel','Green channel','Blue channel');
hold off

[Image Analyst]

Isn't that the very same as Youssef's answer?