HOw to find similar pixels in 3x3 window

Hi all, I have a question to ask,i have 3X3 window of an image such like image below. f(i,j) is center pixel ,so i want to find three most similar pixels except of center pixel in this 3X3 window,please help me regarding this. thanks

[Walter Roberson]

What is the desired output? The values of the pixels or their locations?

[Rehan]

Let say these are the values and i have to find three similar values in this window and have to find mean value of these three similar values.please tell me if still its not clear.

[Walter Roberson]

Most similar to each other, or most similar to the center pixel?

[Rehan]

most similar to each other

Answer 1

[Walter Roberson]

The set of pixels that are most similar to each other are the ones where (x2-x1)^2+(x3-x2)^2 is least. We can also order the pixels first because if x1<x2 and x2<x3 then x3 is less similar to x1 than x2 is to x1

pix = f(i-1:i+1,j-1:j+1);  %entire window
pix = sort(pix(1:4,6:end)); %exclude center
pd2 = diff(pix).^2;  %difference squared
ssq = pd2(1:end-1)+pd2(2:end); %sum of 2 squares
[minval, minidx] = min(ssq);
mean_wanted = mean(pix(minidx:minidx+2));

[Rehan]

got it .Thanks