Calibrating scanner to remove streaks.

[peterjones975]

Hi. Sorry if this is the wrong newsgroup.

I've got a Mustek 1200 UB Plus (cheap and cheerful) scanner. I've
successfully got it running under Linux with Sane with no real
problems.

However, I've tried a few scans and keep getting the same profile
across the scanner image (pinkish streaky lines in certain parts when
scanning a uniformish white piece of paper). I'm guessing that this is
because of a non uniformity in the scanner head as it is always in the
same place along the length of the image.

Does anyone know of any way of compensating for the streaks via some
sort of calibration (I think this would be a deconvolution if my
memory of school maths is anything to go by (increasing the gain for
certain colours for the faulty lines say)).

I know that it is possible to use graphics packages to compensate for
this later on down the line. However, this would be a pain as my
photos will not always be placed in the same point in the scanner. It
seems to me that it is more natural to do this type of compensation in
the scanner side.

Is there a way of doing this (with Linux). As my scanner was cheap (40
GBP) I can't expect much of it. However, it would be nice if there was
another way around.

Thanks,
Pete

 

[lostinspace]

----- Original Message -----
From: <>
Newsgroups: comp.periphs.scanners
Sent: Tuesday, April 27, 2004 4:40 PM
Subject: Calibrating scanner to remove streaks.

Hi. Sorry if this is the wrong newsgroup.

I've got a Mustek 1200 UB Plus (cheap and cheerful) scanner. I've
successfully got it running under Linux with Sane with no real
problems.

However, I've tried a few scans and keep getting the same profile
across the scanner image (pinkish streaky lines in certain parts when
scanning a uniformish white piece of paper). I'm guessing that this is
because of a non uniformity in the scanner head as it is always in the
same place along the length of the image.

Does anyone know of any way of compensating for the streaks via some
sort of calibration (I think this would be a deconvolution if my
memory of school maths is anything to go by (increasing the gain for
certain colours for the faulty lines say)).

I know that it is possible to use graphics packages to compensate for
this later on down the line. However, this would be a pain as my
photos will not always be placed in the same point in the scanner. It
seems to me that it is more natural to do this type of compensation in
the scanner side.

Is there a way of doing this (with Linux). As my scanner was cheap (40
GBP) I can't expect much of it. However, it would be nice if there was
another way around.

Thanks,
Pete

I used a Mustek 600 for six years.
A very simple solution for my 600 was longer warm-up periods for the light.
There exists in the Mustek software a setting for warm-up either
self-detecting (NO-GOOD) or a manual setting.
I learned to allow the initial warm-up to approach 20 seconds and each scan
afterwards to excedd a warm-up of four seconds.
Magically the streaking stopped.

 

[Mr. Grinch]

(e-mail address removed) ([email protected]) wrote in

Hi. Sorry if this is the wrong newsgroup.
Is there a way of doing this (with Linux). As my scanner was cheap (40
GBP) I can't expect much of it. However, it would be nice if there was
another way around.

I'm interested to see if you get any responses. I've got a Mustek 1200 CU
and it also has some issues. Some substance was sticking between the glass
and the plastic guides that slide the the scan element across the glass.
As a result the scanner would get part way then get stuck and stop. I took
it appart and cleaned the glass and sliders several times, and finally it
works again.

TThere are still quality problems with scans being too dark though. I've
been trying the Auto-Correct feature in Photoshop but it's results aren't
always better than the original scan.

Here are some links to some photos I recently scanned. They were scanned
at 600 dpi, which I believe is the highest the 1200 CU goes, not sure about
yours. The originals are much larger PNG files; these are smaller JPGs,
but I can't really tell the difference between looking at them.

I've looked around to see if there are any tricks or software to improve
scans for Mustek scanners, but I haven't found anything for mine yet. I
have come to the conclusion I'll have to get a new scanner at some point.
I've been looking at the HP ScanJet 5550c (2400x2400) or Epson 3170
(3200x6400).

Why those? Because they are the highest end consumer scanners I can easily
get locally, with document feeder support. Anything above that gets into
the business class scanners that are a little too expensive for me. So
far, after reading reviews, it sounds like image quality is good for both,
but I see a lot more complaints about the HP software than the Epson
software.

Sorry I couldn't help more. Hopefully someone else has better advice to
offer you. It's like you said, these Musteks were so cheap it's hard to
expect much.

Best of luck.

 

[Mr. Grinch]

Here are some links to some photos I recently scanned. They were
scanned at 600 dpi, which I believe is the highest the 1200 CU goes,
not sure about yours. The originals are much larger PNG files; these
are smaller JPGs, but I can't really tell the difference between
looking at them.

Sorry, I'm falling asleep at the wheel. Here is the link:
http://tinyurl.com/2mmwn

 

[Dave]

On 27 Apr 2004 13:40:17 -0700, in comp.periphs.scanners,

However, I've tried a few scans and keep getting the same profile
across the scanner image (pinkish streaky lines in certain parts when
scanning a uniformish white piece of paper). I'm guessing that this is
because of a non uniformity in the scanner head as it is always in the
same place along the length of the image.

Like the other responses, I've also had a similar problem.

Opening it and cleaning it, with particular attention to the running rails
solved the problem.

Dave

 

[peterjones975]

Opening it and cleaning it, with particular attention to the running rails
solved the problem.

Dave

Thanks for the replies!

I've had a look at the scanning head itself and it looks spotless from
the outside. I'll have a go at cleaning it tomorrow.

I'm surprised if this is the route cause of the problem as it seems
odd that the streaks are all the same colour (pink). I'm adding a link
to what a thin strip (to reduce image size) of white piece of paper
looks like so you can see what I mean (sorry should have done that
first time).

http://www.geocities.com/peterjones975/

The pink lines keep going along the entire length of the scanner. I
had thought that it was a calibration problem with the sensors.

Thanks again,
Pete

 

[Dave]

On 28 Apr 2004 10:52:57 -0700, in comp.periphs.scanners,

http://www.geocities.com/peterjones975/

The pink lines keep going along the entire length of the scanner. I
had thought that it was a calibration problem with the sensors.

Oh.

I may have mis-lead you on my reply.

In my case the lines were horizontal implying that the scanning head was
juddering as it moved.

Your scan shows it more as a patch than a line. Cleaning the scanner
head, rails and glass may help, but that could also be caused by the CCD
being faulty, the light source being faulty or the synchronisation of the
LED colour flicker being marginal.

Dave