FFTNormalizedCrossCorrelation: Edges and Filtering

Algorithms
1

I know that in most FFT based work, users often need to apply some sort of filter (often butterworth) to fade the edges of the image since FFT assumes infinite space.

how does SimpleITK FFTNormalizedCrossCorrelation function deal with edges? Should I consider adding a filter to remove edge outliers? Is there a way to alter the edge options?

Thank you!

2

Hello @elapins ,

As far as I remember the underlying ITK code relies on the itkMaskedFFTNormalizedCorrelationImageFilter which according to the paper, uses zeros as the boundary condition. To confirm you will need to dive into the code (you never know if an implementation matches the theory without looking at it).

1 Like
3

It is most convenient to apply Butterworth filter in frequency domain. Take a look at how we do it in ITK Montage:

1 Like