I very much like the idea of JBIG and the compression of binary
(black, white, but no gray or other colors) images.
There are, however, some books, at least computer manuals,
written with two ink colors. (Black and blue for example.)
There is, as far as I know, no JTIG compression for trinary
(black, blue, white) images. (Presumably one could allow for
any three colors, likely one being white.)
More specifcally, there are many DEC manuals in bitsavers
that have lost some bits in scanning. If there was a format
to store them in, there might be more interest in doing it.
) I very much like the idea of JBIG and the compression of binary
) (black, white, but no gray or other colors) images.
)
) There are, however, some books, at least computer manuals,
) written with two ink colors. (Black and blue for example.)
)
) There is, as far as I know, no JTIG compression for trinary
) (black, blue, white) images. (Presumably one could allow for
) any three colors, likely one being white.)
)
) More specifcally, there are many DEC manuals in bitsavers
) that have lost some bits in scanning. If there was a format
) to store them in, there might be more interest in doing it.
I think it would be easiest if you split the image in two,
one containing the black text and one containing the blue text.
SaSW, Willem
-- Disclaimer: I am in no way responsible for any of the statements
made in the above text. For all I know I might be
drugged or something..
No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT
> ) I very much like the idea of JBIG and the compression of binary
> ) (black, white, but no gray or other colors) images.
> ) There are, however, some books, at least computer manuals,
> ) written with two ink colors. (Black and blue for example.)
> ) There is, as far as I know, no JTIG compression for trinary
> ) (black, blue, white) images. (Presumably one could allow for
> ) any three colors, likely one being white.)
(snip)
> I think it would be easiest if you split the image in two,
> one containing the black text and one containing the blue text.
Yes, that is fine. But there are no standard compression algorithms,
more specifically, no popular decompression algorithms, that do it.
(Considering some cases where the decompression algorithm is
specified separately from the many possible compression algorithms
that it supports.)
I suppose one could use LZW on two bit/pixel image files, but that
is likely not near as good as JBIG2 on the two separate images.
There may be use for four or five color, but no shading, in some
image systems.
The nice thing about JBIG2 is that it has been supported by PDF
for some years now.
> Yes, that is fine. But there are no standard compression algorithms,
> more specifically, no popular decompression algorithms, that do it.
There are a lot of papers about palette-based compression. Most of the research beats JBIG by a margin in it's own territory, b/w in the end is just a two-color palette.
In your three color case, if you have no better inspiration, just code two planes (a: is it color 0 or the others?, b: is it colour 1 or the others?, c: is implicit).
> glen herrmannsfeldt wrote:
> ) I very much like the idea of JBIG and the compression of binary
> ) (black, white, but no gray or other colors) images.
> )
> ) There are, however, some books, at least computer manuals,
> ) written with two ink colors. (Black and blue for example.)
> )
> ) There is, as far as I know, no JTIG compression for trinary
> ) (black, blue, white) images. (Presumably one could allow for
> ) any three colors, likely one being white.)
> )
> ) More specifcally, there are many DEC manuals in bitsavers
> ) that have lost some bits in scanning. If there was a format
> ) to store them in, there might be more interest in doing it.
> I think it would be easiest if you split the image in two,
> one containing the black text and one containing the blue text.
Just FYI, JBIG2 supports exactly that. We started an AMD on this at around 2006 and it should be long complete by now. I do not remember exactly how it performed.
>> I think it would be easiest if you split the image in two,
>> one containing the black text and one containing the blue text.
> Just FYI, JBIG2 supports exactly that. We started an AMD on this at > around 2006 and it should be long complete by now. I do not remember > exactly how it performed.
I will have to read through it again.
Then the problem is finding the right scanner to generate the scans.
