RE: [boost] VIGRA - Image processing for boost

From: Fernando Cacciola (fcacciola_at_[hidden])
Date: 2001-11-15 11:34:49

----- Original Message -----
From: Philip Nash <philip.nash_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Thursday, November 15, 2001 11:08 AM
Subject: RE: [boost] VIGRA - Image processing for boost

> > I know some of the people within the image processing group were
> > working on
> > 1<<28 bits of map data (B/W); having to use 1<<28 bytes wouldn't be fun.
> > I don't want to say that because of their needs, image<bool> should be
> > packed;
> > but if it isn't that should be clearly stated.
> > Perhaps there should be two image types ?
>
> image_bool, anyone? :-)
>
I don't like the term 'bool' here because the pixel values are rather W/B or
ON/OFF; not true/false.

The correct term used in image processing theory is: binary_image.
(the 'binary' term implies two levels, not the fact that the picture
elements are represented with binary numbers.)

I agree that given the important difference in access time for this kind of
digital image, this should be supported as a separate image type.

However, in my experience, one resort to this representation ONLY when
memory is the primary concern, so I think that a binary_image class should
keep data compressed internally (using RLE, for instance) and not just
bit-packed.
Now, with this in mind, perhaps the path would be to have a
'compressed_image' type, for which 'binary_image' is derived.

Fernando Cacciola
Sierra s.r.l.
fcacciola_at_[hidden]
www.gosierra.com