Tim, a little bit offtopic question but might it make sense to break of the algorithmic parts of Images.jl and put it into some "signal processing" package? I know that the imagemagick dependency is a soft one but all the filtering stuff is IMHO so basic that it belongs to base, or rather into one "signal" package that could be one of the "default packages" that we hopefully get (see https://github.com/JuliaLang/julia/issues/1906)
Tobi Am Dienstag, 4. März 2014 13:43:47 UTC+1 schrieb Tim Holy: > > The main reason to choose one or the other is merely kernel size; for > small > kernels, a direct FIR convolution will be many times faster. > > --Tim > > On Tuesday, March 04, 2014 04:19:31 AM Toivo Henningsson wrote: > > Yes, with sufficient padding, you can compute a linear convolution (of > > finite length vectors) exactly using a circular convolution. The FFT > might > > introduce a little noise in the result, but that is all. > > > > On Tuesday, 4 March 2014 13:12:48 UTC+1, Oliver Lylloff wrote: > > > Well ok, > > > > > > Maybe I misunderstood the whole thing then but since fft assumes > periodic > > > input then I don't see how it can be a linear convolution. I guess > > > Base.conv2 probably uses zero-padding to reduce wrap-around but in > theory > > > it would still be a circular convolution. I'll read up on it :) > > > > > > Best, > > > Oliver > > > > > > Den tirsdag den 4. marts 2014 13.07.20 UTC+1 skrev Andreas Noack > Jensen: > > >> Both conv and conv2 are linear convolutions but the implementations > use > > >> the fft. Maybe the documentation could be more clear on that. > > >> > > >> 2014-03-04 13:01 GMT+01:00 Oliver Lylloff <oliver...@gmail.com>: > > >>> Thanks Tim. > > >>> > > >>> Can't believe I missed that - been working with Images.jl all day. > Nice > > >>> job by the way, very useful. > > >>> > > >>> Best, > > >>> Oliver > > >>> > > >>> Den tirsdag den 4. marts 2014 12.48.01 UTC+1 skrev Tim Holy: > > >>>> Images.jl's imfilter might be what you want. > > >>>> --Tim > > >>>> > > >>>> On Tuesday, March 04, 2014 03:38:15 AM Oliver Lylloff wrote: > > >>>> > Hello all, > > >>>> > > > >>>> > Is anyone aware of a linear convolution implementation? > > >>>> > The Base.conv and Base.conv2 functions are implemented with fft > which > > >>>> > > >>>> makes > > >>>> > > >>>> > them circular convolution functions (as far as I know). > > >>>> > > > >>>> > I'm looking for something alike Matlabs conv2 or SciPys > > >>>> > > >>>> signal.convolve2d. > > >>>> > > >>>> > Should be straightforward to implement though. > > >>>> > > > >>>> > Best, > > >>>> > Oliver > > >> > > >> Andreas Noack Jensen >
