bandpass filter for 2D Data

[Dr. Johannes Zellner]

Hi

does anyone have an implementation of a 2D bandpass filter?

Suppose I've 2d data in a matrix of 1000 x 1000 pixels which
represents a spatial extension of 1 m (1 mm per pixel).
Now I'd like to filter away all frequencies below a wavelength of 50
mm and above a wavelength of 150 mm,
so the resulting data should only have frequencies corresponding to
wavelengths between 50 and 150 mm.

Any octave examples for this?

-- 
Johannes