Help, Image Filters with numpy

[Pete Shinners]

Charles G Waldman wrote:
> The name for the operation you're looking
> for is convolution.  Any book on digital image
> processing will describe this - the book of
> Russ is an good general reference.
> 
> Numeric Python has a "convolve" method but it
> unfortunately only supports 1D convolution.  However
> the filter coefficients you give describe a separable
> kernel - i.e. the 2D convolution is a composition of
> 2 1D convolutions, in the row and column directions
> (this is not true for all convolution kernels).
> 
> Also note that the Python Imaging Library ("PIL") has
> builtin support for convolution filters.
> 
> Finally, if you are convolving with very large kernels,
> it is more efficient to use Fourier transform techniques.


wow, thanks for this abundance of info, charles.
i'll look into PIL, but i'm doing limited operations
on images, and it seems like more than i need.
(that, and "YAD" - Yet Another Dependency, heh)

i'll be sticking with smaller kernels, no larger than
5x5 likely. nonetheless, i've seen a lot about FFT's
but not much 'learning' or 'beginning' info. is there
somewhere i can go to get a handle on the basics of FFT?