I have a Canon LIDE600F recently purchased. I have scanned pages from
books "two up" so that I can lay the book out flat and get two pages
scanned at once lengthwise on the scanner bed. The problem is that
since the pages on a thick book do not lie flat, inside margins of the
pages tend to scan lighter than the rest of the page, almost with a
white bar running up the length of the scanned image towards those
inside margins.

When I then OCR using OmniPage (into which I'm directly scanning the
image), it is almost flawless on most of the page, but loses
characters on those inside edges. This is true even if I up the
contrast or otherwise tweak it.

I have not found the same problem on old scanner, but I think this
uses a different scanning technology than old, large scanners and the
light bounces off the book differently ... or some such. Can anyone
suggest anything? Would using the provided software make a difference
or a different OCR program such as Abby FineReader?

Thanks,
Rich R.

In article <1177715475.414224.86970 (AT) e65g2000hsc (DOT) googlegroups.com>,
richrobinson2005 (AT) yahoo (DOT) com says...

No, different OCR software will not help that problem. The problem is
that the LiDE scanners have CIS sensors instead of CCD sensors.
Meaning, they have no lens to focus the bed onto the scanner, instead
the sensor is just up very close to the paper. This means CIS scanners
have zero depth of field - if the paper is not touching the glass, it
will be out of focus and the OCR will fail. Focus is the wrong term,
there is no lens and no focus, it simply relies on the paper being very
close to the sensor to capture the image, that is, the paper must be
touching the glass. The book pages curve away from the glass at the
binding. As a test, scan the book pages regularly, into an image file,
and you will be able to see this.... why the OCR fails.

The bulky larger-bodied thick scanner models (maybe 6 inches thick
instead of 1.5 inch thick) will have better depth of field for such
purposes. Still not great, but better, at least not zero. The lens
assembly requires that greater room. But this is the price for the
compact thin models.

--
Wayne
http://www.scantips.com "A few scanning tips"

Which scanners are CCD? Are any under $500?

SB

On Apr 28, 9:15 am, Wayne <nos... (AT) invalid (DOT) com> wrote:

In article <1177791979.204536.165230 (AT) n76g2000hsh (DOT) googlegroups.com>,
skybearer (AT) gmail (DOT) com says...

Most are CCD, including the $100 models, except for the thin compact
models, like LiDE, which will be CIS. Just read the specifications, for
sensor, it will say either CCD or CIS.

For books or magazines, CIS means that you have to add a weight or
something, to make the book lay flat, so that the full page is touching
the glass.

--
Wayne
http://www.scantips.com "A few scanning tips"

That's too bad, though I suspected it was only intended for flat
single sheets. Someone wrote that CCD scanners are available for as
little as $100. Are they good quality, at that price? What then are
the recommended uses for CIS vs. CCD scanners in the same price class?
Rich

In article <1177876688.162643.194110 (AT) n76g2000hsh (DOT) googlegroups.com>,
richrobinson2005 (AT) yahoo (DOT) com says...
In the beginning, the CIS models were a way to avoid the manufacturing
cost of the lens and mirror system used by CCD scanners. However all that
can be made pretty cheaply today too, and most scanners are still CCD,
But Canon has had success with their LiDE CIS models.

There are pros and cons to everything. The advantage of your LiDE scanner
is that it is small, thin, compact, weighs less than 6 pounds, needs no
power cord or power source other than the computer... It just doesnt have
any depth of field above the glass bed. Not an issue for flat documents
or photos.

So... you just need to find a way to get your books full page flat on the
glass bed, maybe only scan one page at a time with another books weight on
it, or at least special attention to get the full page flat and touching
the glass bed.

--
Wayne
http://www.scantips.com "A few scanning tips"

Canon has a very affordable CCD scanner of very good quality.
CanoScan 8600F for around $150 or so.