[SciPy-User] Using scipy.signal.fftconvolve() and scipy.signal.convolve()

[Abel Daniel]

On Tue, Jan 18, 2011 at 01:19:24PM -0800, David Baddeley wrote:
> What you're getting form fftconvolve looks about right - with ordinary convolve 
> I suspect your problem might be that you're using 8 bit ints and it's 
> overflowing & thus giving you the random noise pattern. Ffts cast their inputs 
> to double first. I'd suggest casting your image to float - ie: 
> a = a.astype('f')
> before doing the standard convolutions.
Thanks!
Indeed that was the problem, casting as you suggested results in convolve giving
the same results as fftconvolve

Daniel Abel
abli at freemail.hu