Upsampling a matrix with zero elements

I have a matrix x = [1 2 3 4; 5 6 7 8] and I want to upsample it by 2 so it goes something like x = [1 0 2 0 3 0 4 0; 0 0 0 0 0 0 0 0; 5 0 6 0 7 0 8 0; 0 0 0 0 0 0 0 0]

Any suggestion??

Answer 1

[Dyuman Joshi]

%input
x = [1 2 3 4; 5 6 7 8] 

x = 2×4

1 2 3 4 5 6 7 8

%Upsample factor
n=2;

%preallocate the output matrix
y = zeros(n*size(x));

%assign values
y(1:n:end,1:n:end) = x

y = 4×8

1 0 2 0 3 0 4 0 0 0 0 0 0 0 0 0 5 0 6 0 7 0 8 0 0 0 0 0 0 0 0 0

[Stephen23]

+1 good MATLAB approach.

Answer 2

[Bruno Luong]

x = [1 2 3 4; 5 6 7 8] 

x = 2×4

1 2 3 4 5 6 7 8

kron(x, [1 0; 0 0])

ans = 4×8

1 0 2 0 3 0 4 0 0 0 0 0 0 0 0 0 5 0 6 0 7 0 8 0 0 0 0 0 0 0 0 0

[Stephen23]

+1 very neat

Answer 3

[Anjaneyulu Bairi]

Hi,

You can follow the below steps to upsample the matrix by 2.

• Create a matrix with a double number of rows and columns with all zeros.
• Now iterate over this new matrix, and for every odd iteration and odd position, assign the original matrix value.

Code for reference

x = [1 2 3 4;5 6 7 8];
[rows, cols] = size(x);

% Initialize the matrix with double number of rows and columns
new_matrix = zeros(rows * 2, cols * 2);

% Copy elements from the original matrix 'x' to the new matrix
for i = 1:rows
    for j = 1:cols
        new_matrix(2*i-1, 2*j-1) = x(i, j);
    end
end

Hope it helps to resolve your query.