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Extra large format scanners

(Last updated: 31st January 2009)

The KartoScan FB VLS flatbed: probably the largest scanner in the universe!

Synchronicity never ceases to amaze me.

On the day we spotted Colortrac claiming that their new SmartLF Gx+ 56 was "the widest, highest resolution CCD extra large format scanner on the market today", we received a request from Geofoto Scandinavia AS in Norway for a free scanning bureau listing on this website. This led us to their ProCaptura website which cautiously states that "you will probably never see a larger scanner in this universe".

KartoScan FB VLS
KartoScan FB VLS -
It's no joke - it really is...
the largest scanner in the universe!
Scan Area: 4.9m x 1.8m (196" x 72")

On first seeing the image on the right we wondered if someone had not had fun with Photoshop at our expense! We asked Helge Roald, Technical Director of Geofoto Scandanavia, if the photo was for real? He replied "We are a serious company with serious customers… Of course, it is real!"

So, the image on the right shows the actual size of the KartoScan FB VLS (Very Large Scanner). It is BIG, BIGGER even than Colortrac's BIGGEST large format scanner, the new SmartLF Gx+ 56, soon-to-be-crowned king of the extra wide, sheet-fed scanner market, assuming no-one releases an even wider scanner first, of course.

But, BIG as it is, does the KartoScan have a future? Is it not a dinosaur, a relic from the early days of large format scanning when capturing and especially saving long, wide documents at high resolution was difficult, if not impossible. What can it do that a relatively inexpensive, 40"-wide, continuous feed large format scanner with more-or-less unlimited length can't do today?

Scanners4CAD asked Helge Roald, Technical Director of Geofoto Scandanavia, the manufacturer of the KartoScan scanner range, what is its chief benefit today?.

"If you simply want to reconstruct a dimensioned drawing and can read the dimensions of the entities from the drawing, then any cheap large format scanner can be used " said Roald. "Our equipment is much more expensive. KartoScan scanners are for customers requiring the highest level of scanned image accuracy. I’m unaware of any equipment that can beat us here. We don’t like to be compared to continuous feed scanners since the technology and the usage is so different."

"When size and accuracy matters, KartoScan is unique. Most scanners can handle large documents but do so with less accuracy. By "accuracy", I mean the deviation between the original and the digital image. Kartoscan guarantees that any pixel in the large image is less than +- 50 microns (Plus version) or +- 100 microns (Basic version) from its true position in the original. Who needs this? Anyone scanning undimensioned drawings, templates, etc, which need to be accurately vectorized and used for CAM (the aviation industry, for example), a sometimes for mapping," said Roald.

Some background...

Reader Comment

Hawker Harrier VTOL Jump Jet

"When I saw the image of the KartoScan my first thought was "it looks just like the Kongsberg flatbed drafting table we used at British Aerospace Kingston in the late '70s". I continued to read down the page and there it was - "based on Kongsberg drafting machines". We used the Kongsberg for lofting – drawing full size – surface lines for Harrier rear fuselage which had some really tricky surfacing. We also used it do A4 aircraft performance graphs – a bit of overkill on a 144” long drafter!"

John Bennett
Marketing Manager
Allied Images

Founded in 1990, Geofoto Scandanavia is based in Oslo, Norway.

It was previously known as Procaptura, before that Kongsberg Scanners, an arm of Kongsberg Vâpenfabrikk, a supplier of naval defence and space-related systems and products, as well as the manufacturer of a highly accurate, automatic drawing machine. The original Kartoscan scanner was based on Kongsberg drawing machines. As a result, KartoScan's chief constructor uses the term "measuring instrument" rather than "scanner" when describing KartoScan scanning products today.

Kongsberg Scanners first developed the KartoScan solution to give automotive, shipbuilding and aircraft manufacturing industries a means of scanning extra-long J-size engineering drawings. In the NASA Engineering Drawing Standards Manual, Dr Allan Sherman, Director of Engineering at the Goddard Space Flight Center, defines J-size drawings as 34" wide with a length of 48" up to 144". Others describe J-size technical drawings as 34" wide with an unlimited length in inches. The first KartoScan VLS was custom-built for the Boeing Company in 1998.

Geofoto Scandanavia continues to develop and market two types and size of extra large flatbed scanners, the FB VLS and the smaller FB V in four options. Today, its clients are mostly mapping, topographic, hydrographic and geodetic authorities. Most recently, Geofoto Scandanavia has specialised in data conversion technology, designing solutions for developing digital mapping systems which are used worldwide. ProCaptura's expertise in raster map conversion software led the geoinformatics company, Geofoto Scandanavia, to acquire a 76% stake in it in March 2008.

There is much that intrigues about this expensive device. We do not doubt that the FB VLS is "the world's largest flatbed scanner!" If it is not, please tell us what is. However, we wonder what its unique benefit is today. We imagine that one is its software, the reason why ProCaptura was acquired by Geofoto, and the other is its accuracy.

KartoScan FB
ProCaptura KartoScan FB -
sister to the largest scanner
in the universe!!
Scan Area: 1.6m x 1.05m (63" x 42")

The KartoSCan "measuring instrument" in action!

Because the KartoScan's original design was based on a drawing machine, it is probably not surprising that it looks and works much the same as an old pen plotter.

It has a single scanner with a 4900 mm x 1820 mm scanning surface (19" x 7") which is mounted on an steel beam. The camera can move up and down the beam while the beam traverses the scan table, much like a pre-inkjet pen plotter.

Before scanning can start, the document to be scanned must be attached to the KartoScan flatbed scanner board by either a glass plate or a vacuum option. Clearly, this takes longer than the time it takes to feed a single drawing into a sheet-fed scanner. Depending on the size and fragility of the material to be scanned, the pre-scan preparation takes approximately one minute to complete. Tilting the flatbed provides the best work position for attaching, inspecting and cleaning purposes. An 80-85° tilt has proven to be the optimal ergonomic position for using the KartoScan.

KartoScan flatbed scanners offer either a glass plate or a vacuum table option. While it is possible to change between a glass plate and a vacuum table, this requires any change to be fitted by engineers who must also recalibrate the machine. If a customer wants both options, they usually purchase two machines. Geofoto Scandanavia has customers with both the KartoSCan FB V GP (glass plate) and the FB V VT (vacuum table) models. Both use fluorescent tubes for their illumination. These require a warm-up time of 5-10 minutes for color work, less for black / white images.

The GP glass plate model is best for scanning transparent negative images as its backlight option gives black / white images with thin white lines the best results. The GP scanner has its own light source which enables it to scan non-transparent documents. "Tandem Scanning" allows users to attach a drawing to the board of the GP scanner while another document is being scanned. The VT vacuum table model uses reflected light only. It can better handle bulky or thick and also fragile material and is Geofoto Scandanavia's most popular model at present. It has the added advantage of being able to flatten drawings with uneven surfaces, folds and creases.

ProCaptura ScanCenter
ProCaptura ScanCenter -
undertakes large scanning jobs
from all over the world

The KartoScan VLS and FB range are both true 1200 dpi true optical resolution, CCD-based scanners. They use a linear digital camera with a front light (reflected light) source. As the scanning head moves across the drawing, it captures one line of 2048 pixels at a time. Once the scanner head has captured one strip, it moves down the traverse arm to capture the next strip. The KartoScan FB software automatically stitches the scanned strips together as it scans. The scanner gives the option of making either tiles, multi view tiles or strips which it saves as all types of TIFF 6.0 files. For very large files, multi-view tiles are recommended.

As expected of a scanner based on a precison drawing device, KartoScan VLS and FB V flatbed large format scanners are position controlled X-Y instruments. To zoom into a part of the image, the camera's position can be moved in the X, Y and Z directions from a scan panel in the scanning software which allows the user to define the area to be scanned, the resolution, the colour model, file name, etc. However, any Zooming In/Out at this stage will change the resolution which must then be reset. Once a drawing has been scanned, the viewer in the supplied KartoScan software allows zoom and pan, etc, around the image.

Geofoto Scandanavia claim the KartoScan VLS and FB V Basic model flatbed wide format scanners offer absolute accuracy independent of the position of the originals. In contrast, they say, sheet feed scanners have an accumulated error depending on the distance from scan start and therefore give their accuracy as a percentage of the length to be scanned. Typical values for accuracy on a sheet feed scanner are ± 0.1%, an error of 1 mm (0.04") over 1 meter or 2 mm (0.08") over 2 meters.

Geofoto Scandanavia claims that standard configuration KartoScan VLS and FB V Basic model flatbed large format scanners hold accuracy to within ±0.1 mm (0.004") independent of distance. With the option of Enhanced Accuracy in the KartoScan FB V Plus models, the error will be less than 0.05 mm (0.002") independent of distance. They operate with a variable true optical resolution, giving a 1 : 1 relation between the pixel size on the original and a pixel in the CCD array. Geofoto Scandanavia say this is 10 times better than any sheet feed scanner or roller scanner on the market.

Okay, if you want great accuracy, the KartoScan range deliver impressive results. However, some will question how productive a system that scans in strips can be?

Geofoto Scandanavia claim that up to three A0 documents can be captured on KartoScan FBV and VLS scanners per hour at a resolution of 1200 dpi. Such honesty is welcomed as it looks slow by comparison to the enormous number of raw A1 scans which Contex now claims to do in one hour at 200 dpi and which they call "productivity". As Geofoto Scandanavia's modest figure includes the time needed to edit and improve an A0 image scanned at 1200 dpi using the supplied software, their claim is an indication of Real World productivity - and all the more impressive for it.

"Most scanner producers highly focus on scan speed"said Roald. "This is, however, a disparagement of the productivity issue. Selection of resolution, calibrating for light and color, cleaning the original for dust, inspection after scanning, post processing operations like de-skewing and de-speckling, etc. are issues which take time and reduce the productivity. Our scanners offer a range of functions to maximize scanning productivity and ensure excellent results. Looking at the whole conversion process, the time used on scanning is very short compared to all the other preparations, the vectorization process, the loading of data, etc."

DPI50010001200
VLS3.51420.2
FB0.62.63.7

Geofoto Scandanavia claim to scan J-size (34" x 144") documents at 1200 dpi, indeed any size of document, is restricted to a file size of less than 4Gb. The table above shows the number of Giga pixels if the entire scan area is scanned with different resolutions.

KartoScan FB software

KartoScan flatbed scanners run a Linux Red Hat Operating System. Among the software supplied is a basic scanning module, a large file viewer, color and light source calibration tools and a camera adjustment module.

With KartoScan FB software the user can select different color models. With 4Gb being the file size limit, a 5 bit PAL color model is the maximum for a VLS 1200 dpi J-size scan. The software has efficient tools to handle the large amounts of data in these huge files. While a 4Gb file may take some time to process, Geofoto Scandanavia assure us that it works! We have no reason to doubt them.

Several paid-for software option exist. These include:

Prime - image processing software
Prime can handle binary (1 bit), grayscale (8 bit), colour palette (8 bit) and RGB color (24 bit) up to 4Gb in size. Capable of clipping, scaling, rotating, etc, Prime's main purpose is to clean up and improve the quality of the scanned image, specifically line-like objects for the purpose of vectorisation, color separation and color reduction (RGB to PAL). It can batch process scanned images without user interaction once the operator has defined the processing parameters, an activity which significantly increases productivity when performing advanced processing.

GeoRef - interactive graphical transformation software
GeoRef's ability to offer different re-sampling methods to get a scanned image to fit into a desred coordinate system explains much of the KartoScan's popularity within the mapping community. Based on known points, GeoRef will calcualte one or more mathematical transformations which can transform all or part of the image to a desired size. It uses rubbersheeting which Geofoto Scandanavia claim show that it can be adjusted to an accuracy of less than a pixel. Transformation reports list the accuracy of the operator's work done in bringing a drawing back to a desired shape.

Merge - image composition software
Merge makes one image out of multiple scanned images, even if they have different resolutions. The merging of sub-images is a quick interactive process done right after scanning. Geofoto Scandanavia say that "in a production line this rarely becomes a bottleneck." If a drawing is larger than the size of the smaller KartoScan FB scanner, Merge provides tools with which it is possible to accurately combine many sub-images into one image. Overlapping data or attched marks can be used as merge match points. Merge has powerful tools to interactively move different sub-images into position, a process which Geofoto Scandanavia advises with admirable honesty "is normally both slow and inaccurate and should be avoided if high precison data is required".

So, where and how does Geofoto Scandanavia fit into today's market?

The KartoScan FB VLS costs over £1m / USD $1.5m. As it is a specialist piece of extra large size scanning equipment, there are only three models in existemce in the universe.

The smaller KartoScan FB V VT (Plus) costs £250,000 / USD $375,000. This includes one licence of all the software packages (Prime, Merge, GeoRef), a workstation and monitor, a 12 month warranty with installation and basic training. With the KartoScan FB V weighing in at 1100 lbs (500 kg), its delivery and positioning is a logistical consideration.

Despite the highest cost in large format scanning, these devices still sell. Not expecting to get an answer or to be told "several years ago", we asked Geofoto Scandanavia "when was the last time you sold a KartoScan FB V?" We were surprised to be told "December 2008, to Mazovia Poland, Warsaw county, with delivery planned for March 2009".

So, despite an expensive price tag, these devices continue to provide a specialist scanning solution to mapping and aviation industry professionals with a need for exceptional accuracy. Geofoto Scandanavia have a demo model KartoScan FB VLS, the BIG One, in their Oslo office. Anyone interested in seeing it and or the KartoScan FB V range in action should contact Helge Roald via the web site below.

Geofoto Scandanavia A/S:
www.procaptura.com