[Tfug] Hand scanner recommendation?

[Bexley Hall]

Hi John,

--- On Tue, 1/5/10, John Karns <johnkarns at gmail.com> wrote:

> Bexley Hall <bexley401 at yahoo.com> wrote:
> 
> > TIFFs actually *can* use compression.  But, *lossless* (vs the
> > lossy compression used in JPEGs).  However, you tend to end up with
> > bigger files... (of course, there are pathological cases that
> > defy each of the above assertions)
> 
> A common problem I remember having encountered in dealing with TIFF
> images is that I often used to find that none of the image viewing
> apps I had installed would successfully open / view more than about
> 70%-80% of the images I was dealing with.  (This was about 15 years
> ago, so things may be different now.)

I had similar problems.  And, the standard is flimsy about
just what really *must* be supported.  E.g., I implemented
a 2 bit format (4 gr[ae]y levels) and *nothing* would read
it!  :<  So, I had to write a converter to reencode the
images in a 4 bit form (16 levels).

> Without having info on hand to corroborate my supposition, I
> attributed it to the existence of several different compression
> specifications used to create files labeled as being TIFF.  I seem to
> remember having an app to create them which presented various
> compression format options.

TIFF allows you to optionally include lots of different information
in the file -- with suitable "tags".  I think the problem lies in
the fact that most decoders pick and choose which tags they
want to support -- since they aren't *required* to support them!

> I found other image compression schemes to be easier to deal with,
> such as GIF.  However, at the time, there was a movement away from
> distributing images as GIF due to an enforcement of royalty
> collection by the company that held the patent (Unisys).

Yes.  I think PNG is the "politically correct" way to do this, now.

But, when it comes to cameras, you usually just have RAW (analagous
to BMP) format and, possibly, TIFF.  Many cameras won't even let you
set the quality factor on the JPEGs they create (or, if they do,
you are given just two or three "generic" choices:  fine, standard
and coarse... or words -- possibly application-centric -- to those
effects)

The other problem with using cameras is that some cameras have
a disconnect between shutter (button) release and when the image
is *actually* recorded.  These cameras cause me all sorts of problems
as any motion just *after* pressing the shutter release results in
a blurred image.  :<