2D Sliding Window Discrete Fourier Transform
swdft2d(x, n0, n1, type = "fftw")2D input signal
window size in row direction
window size in column direction
algorithm to implement. defaults to "fftw", other option 'fft' for R's base FFT function. R's base fft function is used if 'fftwtools' library is not installed.
An S3 'swdft2d' object. See ?new_swdft for details.