BZSUPPORT: Blitz++ for image manipulation?

[simon <sk2...@ma...>]

Hi Pedro,

I recently found myself in a similar situation.  I started off using
blitz++ Array<  , 2> as a base for an image class.  Things were working
fairly well, excepting a few small bugs.  Unfortunately, I found the
compile times too much for my poor little processors!  As I found
myself often coding on the project on slower machines, I quickly
became frustrated (compiler support for template 'export' would really
help here).

I ended up writing a simpler array class (still n-dim, but less
expression templates and meta-programs, just to fit my needs), but
kept some of the api from blitz++ (e.g.,  image(Range,int) ), and used
this to build a wavelet package on.  I kept things from the api so
that it would be easy to back-port to blitz++, but the design has
diverged a bit now... 

Anyways, I am interested in others comments about blitz++ for imaging
applications, especially in comparison to other approaches.  I am not
familiar with the AIPS++ package; can you comment on the shortfalls of
this code that you hope blitz++ might address?

To address a couple of your questions more directly:

 - My arrays worked well with 5kx5k grayscale images.  I think as
   long as you can keep the whole image in core you will be quite
   efficient with blitz++.

 - I don't think the valarray (it is in the standard library, not the
   STL) is optimal for *any* purpose :)

-- 
Simon Alexander         M.Math student
Applied Mathematics     University of Waterloo



=?iso-8859-1?Q?Pedro_G=F3mez?= writes:
 > Hi,
 >[snip] 
 > -Is a good idea to use the blitz++ classes as image containers? If yes, are
 > there any
 > performance concerns for such a large images.
 > -Are there other C++ libraries to deal with this kind of data?. For example
 > the
 > astronomical processing software AIPS++ has the "lattice" class as an
 > abstract class
 > from which other specialized classes are derived.
 > -How about the STL valarray for this purpose?.
 > 
 > Thanks in advance,
 > 
 > Pedro Gómez
 > 
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