Many Kofax customers have asked for our advice to enable them to get full rated speed from their scanners. The tips that follow were created by Dean Hough, VP of Engineering and a co-founder of Kofax. This is a short summary that identifies some of the most common issues that affect actual scanning performance. We hope you can use it as a guide to improving your scanning throughput.
Most scanner ratings apply to 200 dpi letter size (8.5"x11") pages. At 300 or 400 dpi or at larger page sizes, throughput will be significantly slower. Note that A4 pages are 10% slower because they are longer than U.S. letter pages.
A scanner's ADF has rollers that wear out and will have difficulty feeding pages. Many scanners must have their rollers cleaned every few months; some have a tension setting on their ADFs.
A scanner's lamp will become weaker over time and the scanner might have difficulty calibrating itself. We have seen this lamp intensity cause many strange conditions. The glass platen must also be cleaned periodically. Weak lamps and dirty platens cause noisy images that reduce system performance.
The firmware in a scanner might be out of date. We have upgraded our drivers to support the latest features of a scanner and in the process had older scanners in the field not behave properly.
Some Kofax boards might not have enough memory on the board to run with a high speed scanner. Also be sure that the pre-scan setting is set high enough to ensure overlapped pipelining.
The Kofax product being used might not have the correct driver version. Many times a driver version mis-match will still scan but unforeseen changes will result.
Busy or noisy images cause poor compression ratios that slow system performance. A compressed image must go across the PC's bus and can become a bottleneck, slowing scanning to less than half the rated speed.
Noisy (dirty) or crooked images will take longer to process, especially if despeckle or deskew are utilized.
Barcode recognition is usually very fast unless the settings are incorrect. It can take a long time to search for a barcode if all directions need to be searched. When possible, our advice is to use only 0 and 180 degrees. Adding 90 and 270 degrees will cause a slowdown on the faster scanners. The Kodak 923, for instance, reduces from 160 ipm to 80 ipm when 90 and 270 degrees are turned on and even slower when all 4 directions are searched. The Bell+Howell 6338 reduces only slightly from 82 ipm to 78 ipm using 90 and 270 degrees but declines to about 60 ipm with all 4 directions turned on. ImageControls v2.0 will correct this problem.
The width setting is also a factor if it is not correctly specified. Our testing shows a decline of 2-4 ipm when a width of 0 is entered.
The quality setting also has a performance impact. Setting the quality to poor forces many retries to find the barcode. If the barcode is a label or a first generation laser-printed barcode, a setting of 'normal' or 'good' quality will improve performance. Also note that barcode recognition can take 10 times longer than normal if a page doesn't have a barcode since the algorithm tries every possible way to find a barcode.
The PC's CPU needs to be fast enough to process the disk activity, image display activity, and any application overhead that might be taking place. Some image processing functions in ImageControls 2.0 take place on the PC's CPU and this can slow down scanning on slow PCs.
The PC needs to have a fast disk to store the compressed scanned images. Note that disk performance changes. A disk will slow down when it becomes fragmented or has media errors. A networked server disk can become much slower depending upon other users and network traffic.
Sometimes the network topology or network drivers can dramatically reduce file transfers and bottleneck the scan process. Be sure your network is running well prior to adding an imaging system. An underperforming network will slow to a crawl once scanning traffic is added to it.
While this list is not complete, it should provide a starting point to improve your scanning operations. We will continue to update this document so feel free to provide feedback through our support engineers or via support@kofax.com.
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