Finding an average of sample point in an array with irregular intervals

Hi!

I would like to take an average of sample windows in my data.

(I1 = [1:10])

For regular intervals i could use the

Av1 = mean(I1([1:2:10;2:2:10])) 

However, i am currently facing a problem where a gap between windows increases every time by 1 unit. Sort of like that:

Av2=mean(I2([1:(1:4):10;2:(1:4):10])) 

How can i do it in Matlab?

[Image Analyst]

Have you tried a nested for loop? Try it.

[Pavel Kutsenko]

sorry, i have no idea how to implement this

Answer 1

[Omer Yasin Birey]

Hi Pavel, you may try this

Av2 = cell(4,4);
% I2 = rand(20,20,20);
for i = 1:4 
    for j = 1:4
        
        Av2{i,j}=mean([I2(1:i:10),I2(2:j:10)]);
    end
end
meanWind = mean(cellfun(@(c) c, Av2(:)));

[Pavel Kutsenko]

no error, byt Av2 is a matrix 4x4 and meanWind is only one number. is there a way of getting answer as an array, of four numbers (in this case)? Av2=[2,3,5,8]

sorry to bother

[Omer Yasin Birey]

Of course, it is possible. You are changing the columns here so I assumed you want to calculate the mean of columns. You can use the code below for mean of columns. Else if you want to take mean of rows use the second code.

Av2 = zeros(4,4);
% I2 = rand(20,20,20);
for i = 1:4 
    for j = 1:4
        
        Av2(i,j)=mean([I2(1:i:10),I2(2:j:10)]);
    end
end
meanOfEachColumns = mean(Av2',2);

if you want the mean of rows

Av2 = zeros(4,4);
% I2 = rand(20,20,20);
for i = 1:4 
    for j = 1:4
        
        Av2(i,j)=mean([I2(1:i:10),I2(2:j:10)]);
    end
end
meanOfEachColumns = mean(Av2,2);

[Pavel Kutsenko]

But i dont really have rows or columns, i just have an array of numbers. So if I use this code with I2=[1:10] i get (5.6, 5.3, 5.6, 5.4) as my means and i am looking for (2,3,5,8)