Re: [boost] [GIL] image rescale algorithms

Subject: Re: [boost] [GIL] image rescale algorithms
From: Est (esteban_at_[hidden])
Date: 2009-09-11 06:45:09

Nicolas,

One last, small thing. I would rename bicubic_filter
in filters.hpp to mitchell_filter. Bicubic filter is a
common name for bspline or photoshop style filters and
mitchell is different.

I think rgba32f_pixel_t is a good model for hdr pixels.
I don't see the 0..1 range in floating point channels as limits.
And GIL does not enforce them in any way.
They only define a mapping between integer and floating point channels.
In this case (rescale), clamping is an "artifact" of using integer 
channels and filters with possibly negative weights.

I did some informal profiling, on a dual core machine, using the bicubic 
filter, I got this

Big images:

rescale serial took 9167.86 milliseconds (9.16786 sec)
rescale parallel took 5055.94 milliseconds (5.05594 sec)

Small images:

rescale serial took 1923.46 milliseconds (1.92346 sec)
rescale parallel took 1104.4 milliseconds (1.1044 sec)

Est.