[Insight-developers] Re: integrating the new algorithms for existing filters in ITK

[Luis Ibanez]

Hi Richard,

I recall that Jim have posted comments related to the padding.

Could you give us an indication of what is the magnitude of
RAM penalty versus the gain in computation time ?

Depending on that ratio, it may or may not be worth diverging
from the current coding practices.


   Thanks for any hint,


      Luis


---------------------
Richard Beare wrote:
> Just a note about the reconstruction filter - there is some ugliness
> relating to performance experiments in that class that will need to be
> removed.
> 
> Those experiments highlight a general problem about how difficult it
> is to design efficient general pupose boundary conditions. In queue
> based morphological algorithms a common strategy is to pad the images
> with a max or min to provide a border. In itk this can be done
> explicitly or implicitly - explict padding results in a quicker
> filter, but higher ram usage. Optimization using face calculators is
> not an option in many cases. Sacrificing a border pixel is also
> possible to improve performance.
> 
> The same strategy can also be used in watershed and regional extrema 
> filters.
> 
> It would be nice if we could establish a few conventions that support
> these options consistently.
> 
> 
> 
> On 12/11/06, Gaetan Lehmann <gaetan.lehmann at jouy.inra.fr> wrote:
> 
>>
>> Hi Luis,
>>
>> The new connected component and morphological reconstruction filters done
>> by Richard are ready for a long time now, and work very well.
>>
>> The reconstruction filters are a lot faster, and much important, are a 
>> lot
>> more efficient concerning memory usage.
>>
>> The connected component is a lot more efficient, gives consecutive 
>> labels,
>> and is able to label an image containing 255 objects with a 8 bit pixel
>> type - the current filter nearly always fail in that case. This last
>> feature let the user decrease the memory usage, which is quite important
>> for me currently.
>>
>> I have put those filters in my ITK tree (not in the nightly test builds
>> this time :-) ) and all the tests are ok. Can I put those new algorithms
>> in the cvs repository ?
>>
>> Thanks,
>>
>> Gaetan
>>
>>
>> -- 
>> Gaëtan Lehmann
>> Biologie du Développement et de la Reproduction
>> INRA de Jouy-en-Josas (France)
>> tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
>> http://voxel.jouy.inra.fr
>>
>