Having the 'soft' probabilities available is definitely a useful improvement (cleanup, fuzzy post-processing), and I'm glad you implemented that!
Josh
On Monday, August 20, 2012 4:11:45 PM UTC-5, Emmanuelle Gouillart wrote:
Hi Josh,
extending the random walker algorithm to multichannel images sounds like
a very nice idea, and I'm sure that it would be useful for other people
(including myself!).
In fact, I had started working on some improvements of the random walker
code but didn't go as far as proposing the pull request. I have a branch
for that on
https://github.com/emmanuelle/scikits.image/tree/fix_random_walker, maybe
you can include these changes when you contribute your changes?
Cheers,
Emmanuelle
On Mon, Aug 20, 2012 at 10:03:53AM -0700, Josh Warner wrote:
> I have modified the existing random walker algorithm into a fully
> backwards-compatible version which allows inclusion of multispectral data,
> e.g. RGBA channels or different (registered) image modalities. �I really
> liked the existing algorithm, so I just extended it rather than write one
> from scratch for my own purposes. �The overhead is minimal; multispectral
> processing is triggered if data is passed as an iterable of arrays rather
> than just an array. �
> This amounts to combining image gradients as sqrt(sum-of-squares) and
> dividing by sqrt(#channels). �For obvious reasons, the several channels
> must be pre-processed to have data on similar ranges by whitening or a
> similar method. �Not usually a problem for RGB, but in medical imaging
> this rears its head.
> Would this be of interest to the community? �I'd be happy to contribute
> the changes if there is interest.