skimage and opencv

[Emmanuelle Gouillart]

	Hi Fran�ois,

	that's an excellent question, and not a troll :-). Opencv is a
very powerful library, but it focuses primarily on computer vision
(feature detection and extraction, classification, ...), as opposed to
image processing in general (with other tasks such as denoising,
segmentation, ...). 

	The other big difference is that skimage builds on numpy
ndarrays, and uses the full power of the numpy API (including of course
the basic facilities for processing arrays as images that come with
numpy), as well as some of scipy functions (you could have added
scipy.ndimage to your list -- a few functions in skimage are wrappers
around scipy.ndimage, that exist for the sake of completeneness). One
important consequence is that algorithms working for 3-d or even n-d
images can be easily implemented in 3-d/n-d in skimage, whereas opencv is
restricted to 2-D images (as far as I know). Thanks to the use of numpy
arrays, the API of skimage is also quite pleasant for a numpy user, more
than the API of opencv.

	A related difference is that skimage is written in python and
cython, whereas opencv is a C++ library. The two libraries attract a
different crowd of developers, and a Python/Cython toolkit based on numpy
arrays is easier to develop and maintain inside the Scientific Python
ecosystem. 

	I'm sure that other devs/users will have things to add to this
discussion!

	Cheers,
	Emmanuelle

On Thu, Dec 27, 2012 at 02:06:08PM -0800, Fran�ois wrote:
>    Hi users and devs,

>    It came to my knowledge that another python library (based on C++ and C
>    codes) for image processing exists too : opencv
>    I understand that numpy intregrates some basic features and we need some
>    advanced features but I have the feeling that skimages is redoundant with
>    opencv in some ways.
>    What's the position of skimage about that? (Don't read this question as a
>    troll but like a real question).
>    I mean that similar features exist in both. Would not be possible to
>    reuse/integrate opencv or merge? what's the reason for keeping them apart?

>    My observation is there is 4 libraries to manipulate images:
>    * PIL
>    * numpy
>    * skimages
>    * opencv
>    That's a lot.

>    Cheers,