NO BULL: Scan Speed Part 2
Contex define large format scanner productivity in "drawings per hour"
... Continued. [Contex Scan Speed - previous] [Contex Scan Speed - next]
Towards a new measure of wide format productivity
The Image Access WideTEK -
It's FAST!
Thomas Ingendoh, the thoughtful CEO and President of Image Access, the German manufacturer of the WideTEK range of large format scanners, believes it is possible to measure wide format scanning productivity correctly and fairly.
His Image Access large format scanners are rated "the fastest large format scanner in the world" by BERTL. Uniquely operating system independent, the Image Access WideTEK series has the raw speed and power to go head-to-head with the Contex SD Series. But scanning speed alone does not tell the user the full story, says Ingendoh. He writes the following:
Large Format Scanning Speed - which is the right productivity measure?
Image Access WideTEK 36 with USB stick.
Traditionally, wide format scanner vendors have specified the transport speed of their scanners under various circumstances and declared this speed to be the scanning speed. This is true only when the scanner is designed to do a full scan on its own, without halting mid-scan for data throughput reasons, as is the case with Image Access scanners. Contex and many other vendors stop the scanning process whenever the scanner, the attached computer and/or the USB device is no longer able to handle the data rate.
But scanning speed alone does not tell the user the full story. Sheet feed scanner vendors specify pages per minute or images per minute, which is a good approach because it takes the whole digitalization process into consideration; including the document feeding, all image processing and data transfer. Because the feeding process is mechanical and the one minute time frame is short enough not to require human interaction, this is a consistent measurement, realistically repeatable.
The new specification introduced by Contex is measured in documents per hour. It implies that this rate of throughput can actually be reached. We find this speed specification misleading because calculating scanning for a period of one hour does not take into consideration the human factor; measuring performance which cannot be consistently repeated nor does it relate to the real world.
Image Access WideTEK 48.
In the video available for download at the URL below, you will see an operator scanning at a rate of approximately 800 documents per hour. I think most readers would agree, nobody can consistently keep up production at this speed for a full hour.
To view this video, you will need to download this file and unzip it.
Our conclusion is that Contex extrapolated the speed specified in documents per hour from real world measurements of only a few seconds.
(EDITOR'S NOTE: This is correct. Scanners4CAD had a hand in this by advising Contex that scans per hour was a preferable measure to scans per 15 or 30 minutes. Scanners4CAD realises now that it was wrong. Scanning 744 A1 documents in one hour is not practically achievable.)
In our view, the best approach would be to specify the cycle time for a given document size at various resolutions. The cycle time is the time it takes to scan one document until the scanner is ready for the next document. The cycle time will also largely depend on the image processing and compression used during the measurement, therefore these parameters must be specified. Our proposal for a fair comparison which would be most valuable to the customers can be found in the following table:
Cycle time black and white A1 size document, TIFF G4 stored on hard disk.
| Resolution | 200*200dpi | 300*300dpi | 400*400dpi | 600*600dpi |
| Fastest | xx seconds | xx seconds | xx seconds | xx seconds |
| Best quality | xx seconds | xx seconds | xx seconds | xx seconds |
| Worst case | xx seconds | xx seconds | xx seconds | xx seconds |
Cycle time 24bit A1 size document, JPEG compressed, stored on hard disk.
| Resolution | 200*200dpi | 300*300dpi | 400*400dpi | 600*600dpi |
| Fastest | xx seconds | xx seconds | xx seconds | xx seconds |
| Best quality | xx seconds | xx seconds | xx seconds | xx seconds |
| Worst case | xx seconds | xx seconds | xx seconds | xx seconds |
The fastest scan mode is achieved with all extra time consuming features turned off. The best quality scan mode should include all the automatic features like crop and deskew, auto exposure, de-speckle etc. JPEG and other quality determining factors should be at the maximum. The worst case scanning mode should represent the slowest cycle time possible. This could include time consuming options like 90° rotation, paper rewind or similar.
We should leave it up to the customer to calculate his specific “Productivity measure” because it largely depends on the document preparation process rather than on the bare speed of the scanner itself.
Image Access GmbH:
www.imageaccess.de
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