What is the 2D FFT?
2D FFT (2-dimensional Fast Fourier Transform) can be used to analyze the frequency spectrum of 2D signal (matrix) data. Conversely, 2D IFFT (2-dimension Inverse Fast Fourier Transform) is able to reconstruct a 2D signal from a 2D frequency spectrum.
What is 1D FFT and 2D FFT?
Just look at the math for 1D vs 2D FFT. In the 1D case, there is only 1 independent variable (x[n]). In 2D, there are two. It doesn't make sense to apply a 2D signal (i.e. two independent variables such as rows&columns in your image example) to a function that only takes one independent variable.
What is DIT FFT algorithm?
DIT (Decimation in time) and DIF( Decimation in frequency) algorithms are two different ways of implementing the Fast Fourier Transform (FFT) ,thus reducing the total number of computations used by the DFT algorithms and making the process faster and device-friendly.