Scanning and stitching large items - question

  • Thread starter Thread starter Jack
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J

Jack

I have been using an HP Scanjet 4600 to scan LP covers in four sections
and then using PanoTools/PTAssembler to stitch the four scans together.

I have gotten to the point where the stitching is about as perfect as I
can get it and I am very satisfied with the results. If anyone is
interested in the technique, I would be happy to post it here.

But I am NOT happy with the scanning results that I am getting with the
Scanjet 4600. At the time that I bought it, it was the only choice that
had a truly FLAT scanning surface. There is no raised plastic border
surrounding the glass that the item to be scanned is placed against. The
scanning side separates easily from the side that is normally the lid
in other flatbed scanners allowing an over-sized item to hang over the
scanner on all four sides.

The 4600 is bundled with the most bloated scanning program, or program
of any kind, that I have ever encountered. It was over a year before I
discovered that HP provided two separate TWAIN drivers that would make
using the bloatware unnecessary. The problem is that none of the drivers
produces satisfactory scans. The reasons are several and don't merit
mentioning unless someone is interested.

So my question to those who might be reading this is, are there any
flatbed scanners available that would allow me to do what the Scanjet
4600 allows, and that is, to lay an over-sized item such as an LP cover
on it and have the item lay perfectly flat on the glass even though it
hangs over on all four sides of the scanner?
 
Jack said:
I have been using an HP Scanjet 4600 to scan LP covers in four
sections and then using PanoTools/PTAssembler to stitch the four
scans together.
Click to expand...

In case you haven't tried it yet, I'm getting great results with
auto-blending (on regular panos) with the SmartBlend helper program,
fully supported by PTAssembler. It's worth a try IMO, it can be found
here:
http://smartblend.panotools.info/

SNIP
So my question to those who might be reading this is, are there any
flatbed scanners available that would allow me to do what the
Scanjet 4600 allows, and that is, to lay an over-sized item such as
an LP cover on it and have the item lay perfectly flat on the glass
even though it hangs over on all four sides of the scanner?
Click to expand...

I don't know about similar flat designs, but I do know that on several
scanner models (in particular those that have fixed focus and a
transparency option), best focus is obtained slightly above the glass
platen. So maybe it's worth a try to slightly lift one end/corner with
a spacer. If you need to scan lots of covers, you might even want to
construct a thin removable frame along the edge to lift the cover from
the glass surface. Depending on where the scanner's best focus is, you
might improve the resolution a bit, and you'll avoid Newton's rings on
glossy surfaces. It's just a thought ..., and it would widen your
scanner options.

Another option would be to let PTAssembler correct for the perspective
distortion that results from one edge being higher than the opposing
one (assuming the average focus is acceptable, and sagging is not an
issue). You can set a Yaw or Pitch (always the same amount for a given
scanner) depending on the orientation (PT can probably find the best
values by itself), in addition to the 'd' and 'e' shift parameters you
are probably using.

SmartBlend might also be able to automatically adjust for some
non-uniform lighting that a scanner may exhibit.
 
I have been using an HP Scanjet 4600 to scan LP covers in four sections
and then using PanoTools/PTAssembler to stitch the four scans together.

I have gotten to the point where the stitching is about as perfect as I
can get it and I am very satisfied with the results. If anyone is
interested in the technique, I would be happy to post it here.

But I am NOT happy with the scanning results that I am getting with the
Scanjet 4600. At the time that I bought it, it was the only choice that
had a truly FLAT scanning surface. There is no raised plastic border
surrounding the glass that the item to be scanned is placed against. The
scanning side separates easily from the side that is normally the lid
in other flatbed scanners allowing an over-sized item to hang over the
scanner on all four sides.

The 4600 is bundled with the most bloated scanning program, or program
of any kind, that I have ever encountered. It was over a year before I
discovered that HP provided two separate TWAIN drivers that would make
using the bloatware unnecessary. The problem is that none of the drivers
produces satisfactory scans. The reasons are several and don't merit
mentioning unless someone is interested.

So my question to those who might be reading this is, are there any
flatbed scanners available that would allow me to do what the Scanjet
4600 allows, and that is, to lay an over-sized item such as an LP cover
on it and have the item lay perfectly flat on the glass even though it
hangs over on all four sides of the scanner?
Click to expand...
Are you unhappy with the scanner or the software? Why not try
either SilverFast or Vuescan and see if they work for you. Usually
OEM scanner software is designed to do too much and ends up
clipping the extreme densities. I haven't look recently to see
if there is a trial version of SilverFast, but there is of Vuescan
so you have nothing to lose (except a little time) buy giving it
a try.

I have some tips on scanning and stitched panoramas on my web site which
may also help. Just follow the tips link on the home page.
 
Robert

I am unhappy with the banding problem that this scanner is plagued with.
Alternate vertical bands of lighter and darker brightness about one inch
wide appear to varying degrees depending on what is being scanned. These
bands show up using three different drivers that are available to the
scanner that I know of, so I am thinking it is a hardware problem.

I have Vuescan downloaded and will give it a try.

Thanks,
Jack
 
Robert

Thanks for the heads up on Vuescan. I just tried it and I'm thoroughly
impressed so far. The colors are right and consistent throughout the
scan and the banding is virtually nonexistent.

The software provided with this scanner by HP is pure applesauce in
comparison. Time for coffee and fresh air then another round of tests.

JACK

 
Jack said:
Robert

Thanks for the heads up on Vuescan. I just tried it and I'm thoroughly
impressed so far. The colors are right and consistent throughout the
scan and the banding is virtually nonexistent.

The software provided with this scanner by HP is pure applesauce in
comparison. Time for coffee and fresh air then another round of tests.

JACK
Click to expand...

The complaint was about the HP 4600. I have a 4670 which seems to work
fine. I bought it to scan a lorge map, which I do by laying the map on
the floor and just using the scanning half of the sandwich, moving it
carefully to keep it square with horizontal and vertical and allowing
enough overlap for the stitching software to work with.

The 4670 lloks a lot like a photo of your 4600 excpet that the scanner
body (which you look through) is held in a glass stand (which you don't
have to use). I haven't notice any problem with focus. The software
package, alas, seems to be about the same.

In another post soembody suggested the focal plane of a 4600 might be
above the glass. Instead of the tilt idea, why not just buy a piece of
plate glass (taping the edges) to use as a spacer?

Brendan

 
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