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From: Ullrich Koethe (u.koethe_at_[hidden])
Date: 2001-11-15 12:08:00

Fernando Cacciola wrote:
> 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.

Yes, an RLE image class makes much sense to me. Among other benefits, it
allows for extremely fast morphological filters (erosion, dilation etc.)
because they can operate directly on the RLE images, without
decompression. (AFAIK, such optimized filters are part of the HALCON
image analysis system.)


|                                                                |
| Ullrich Koethe  Universität Hamburg / University of Hamburg    |
|                 FB Informatik / Dept. of Computer Science      |
|                 AB Kognitive Systeme / Cognitive Systems Group |
|                                                                |
| Phone: +49 (0)40 42883-2573                Vogt-Koelln-Str. 30 |
| Fax:   +49 (0)40 42883-2572                D - 22527 Hamburg   |
| Email: u.koethe_at_[hidden]               Germany             |
|        koethe_at_[hidden]                        |
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