Do I have to flip my kernel when performing an FFT-based convolution?
Flipping &amp; dragging is an animative method used in graphical computation of convolution in time (or space) domain. It is the result of an argument manipulation in $h[n-k]$ (or $x[n-k]$) signal animated as a function of n, but drawn on an axis of k, in the convolution sum: $$y[n] = x[n]*h[n]=\sum {x[k]h[n-k] }$$ On the other hand in frequency domain DFT (FFT) based convolution implementations you don't need it as you simply multiply the two DFTs.