Re: bandpass filter for 2D Data

[Dr. Johannes Zellner]

Do you have some code of your low pass filter?

-- 
Johannes



2009/8/27  <address@hidden>:
> Color?
>
> If luminance, only I would (symbolically represented)
>
>>> image1 = lowpass(image,20);
>>> image2 = lowpass(image,50);
>>> then,
>>> imageresult = image1 - image2;
>
> I low pass filter my 2D images using a custom filter function I wrote that
> preserves the 'slope' at the edges.  Does NOT preserve curvature, but at
> least doesn't "squash" the edges towards zero.
>
> Robert
>
>> 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
>
>
>