How can I get the mean of my rgb2gray image and show the new image?

so far, i have ....

RGB = imread('project1.png');
A = imresize(RGB, .25 );
figure(1)
imshow(A)

%%gray scale

I = rgb2gray(RGB);
B = imresize(I, .25);
figure(2)
imshow(B)

%%mean color

m = mean(B(:)); % how do i get the mean of the gray image and then show it
figure(3)
imshow(m)

Answer 1

[Jatin Singh]

Hi Rebecca,

As per my understanding you are trying to display an image with the mean value of the gray image.

To do that you have to display an image where each pixel has same value equal to the mean. The “imshow” function expects an image matrix, but the code is providing a scalar value equal to the mean.

Here is something you can do:

%mean color 
m = mean(B(:));  

%creating an image array of pixel value equal to mean 
meanImage = uint8(m * ones(size(B))); 
figure(3) 
imshow(meanImage) 

Note: This is the code that does what you want but using this will give all pixels the same value.

Kindly refer this documentation about what “uint8” does:

https://www.mathworks.com/help/matlab/ref/uint8.html

Hope this helps!

[Walter Roberson]

Note that there are multiple ways of constructing the mean image, including

meanImage = repmat(uint8(m), size(B));
%or
meanImage = uint8(m) + zeros(size(B), 'uint8');
%or
meanImage = uint8(m) .* ones(size(B), 'uint8');