It seems you are trying to perform a 3D Fourier transform on a 2D data matrix using MATLAB's fftn function. Since the original data is 2D, you will need to extend it into a 3D matrix. Here's a how you can achieve this:
- Replicate your 2D matrix along the third dimension to simulate a 3D dataset.
- Apply the fftn function to perform the 3D Fourier transform.
Here's an example in MATLAB:
% Assuming S is your 2D matrix
S = rand(10, 10);
% Extend S to a 3D matrix by replicating it along the third dimension
S3D = repmat(S, [1, 1, 10]); % Creates a 10x10x10 matrix
% Perform 3D FFT
Y = fftn(S3D);
% Y will be a 3D matrix of the same size as S3D
The output Y will be a 3D matrix containing complex numbers that represent the amplitudes and frequency components of your data. While meshgrid is helpful for creating coordinate grids for plotting, it is not required for using fftn.
For more information on fftn, refer to the following documentation link:
Hope this helps.
