grey 4bit/pixel

Shashi krishna M.S. wrote:
> hi, 
>  
> iam searching a scanner that supports at about 300 dpi
and 4 bit /pixel grey 
> scanner. i found from the scanner that most of the
scanner support 8/16 bit 
> depth in grey mode. 
>  
> is there any way to modify this code to support 4 bit
grey scale depth per pixel. 

well, the source code of scanimage, xsane etc is freely
available ;)

> all suggestions are welcome 

- look for a (documented) file format that supports 4 bit
images (or
  define your own format ;)
- patch scanimage or another frontend so that it can write
the scan
  data in the format you selected. Alternatively, you can
convert
  existing 8 bit images, as produced by a Sane frontend,
with a
  converter program. I am not aware of any 4 bit image
formats, but
  if they exist, you might already find such a converter in
the
  usual Linux distributions. Otherwise, write one. The PPM,
PGM, PBM
  formats (default for scanimage output) are very simple,
and it is
  quite straightforward to read them with C, Python, Perl,
Java or
  whichever other programming language.

Abel

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On Sat, 19 Aug 2006 14:56:58 +0200, abel deuring
<adeuringgmx.net> wrote:

> Shashi krishna M.S. wrote:
>> hi,
>>
>> iam searching a scanner that supports at about 300
dpi and 4 bit /pixel  
>> grey
>> scanner. i found from the scanner that most of the
scanner support 8/16  
>> bit
>> depth in grey mode.
>>
>> is there any way to modify this code to support 4
bit grey scale depth  
>> per pixel.
>
> well, the source code of scanimage, xsane etc is freely
available ;)
>
>> all suggestions are welcome
>
> - look for a (documented) file format that supports 4
bit images (or
>   define your own format ;)
> - patch scanimage or another frontend so that it can
write the scan
>   data in the format you selected. Alternatively, you
can convert
>   existing 8 bit images, as produced by a Sane
frontend, with a
>   converter program. I am not aware of any 4 bit image
formats, but
>   if they exist, you might already find such a
converter in the
>   usual Linux distributions. Otherwise, write one. The
PPM, PGM, PBM
>   formats (default for scanimage output) are very
simple, and it is
>   quite straightforward to read them with C, Python,
Perl, Java or
>   whichever other programming language.
>
> Abel
>


'XnView' should do the job.

Wolfram Heider

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On Sat, 19 Aug 2006, abel deuring wrote:

> Shashi krishna M.S. wrote:
> > iam searching a scanner that supports at about 300
dpi and 4 bit /pixel grey
> > scanner. i found from the scanner that most of the
scanner support 8/16 bit
> > depth in grey mode.
> >
> > is there any way to modify this code to support 4
bit grey scale depth per pixel.

Why?  What constitutes a good answer might depend on it.

> - look for a (documented) file format that supports 4
bit images (or
>   define your own format ;)
> - patch scanimage or another frontend so that it can
write the scan
>   data in the format you selected. Alternatively, you
can convert
>   existing 8 bit images, as produced by a Sane
frontend, with a
>   converter program. I am not aware of any 4 bit image
formats, but
>   if they exist, you might already find such a
converter in the
>   usual Linux distributions. Otherwise, write one. The
PPM, PGM, PBM
>   formats (default for scanimage output) are very
simple, and it is

None of those formats support 4-bit data.
They do support maxlevel=15 data, but the data are
represented with 8-bits.
PBM (P4) is one bit per pixel.  If you want you could stack
4 pbm images.

>   quite straightforward to read them with C, Python,
Perl, Java or
>   whichever other programming language.

-- 
Mike   hennebryweb.cs.ndsu.NoDak.edu
"it stands to reason that they weren't always called
the ancients."
                                                      -- 
Daniel Jackson


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>>   usual Linux distributions. Otherwise, write one.
The PPM, PGM, PBM
>>   formats (default for scanimage output) are very
simple, and it is
>
> None of those formats support 4-bit data.
> They do support maxlevel=15 data, but the data are
represented with 8-bits.
> PBM (P4) is one bit per pixel.  If you want you could
stack 4 pbm images.
>

gif does. i use it every day in 4 bit mode

allan

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what you don't know.
money isn't our god, integrity will free our souls" -
Max Cavalera

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