Scanners

The function of a document scanner is to create a digital image from paper as quickly, reliably and easily as possible

Headway Technology has long been regarded by the industry as the most effective technical distributor, specialising in the data and document management market. Headway's trusted reputation has been born out of an exceptional heritage for delivering succesful application driven solutions, designed to fully address a business issue or requirement. By operating as a manufactures' representative for the leading brands, Headway works closely with re-sellers and their end users, applying the best technologies and product features where they're most needed.

Scanning – Headway offer only the very best range of scanners for distributed capture through to high end centralized scanning from leading manufacturers including Böwe Bell + Howell, Canon, Kliendienst, Kodak, Fujitsu, Panasonic and Visioneer.

The initial decision of colour or bi-tonal will have significant impact when choosing the preferred resolution, it is best to go for the minimum that your particular application dictates. Generally, the higher the resolution that a scanner scans at, the slower it will go. If a scan head has to scan 400 lines in every inch (400 dpi) it will take longer than it does to scan 200 lines to the inch (200 dpi). The other consideration is the storage space required for these images. Storage overheads are dependant on the resolution of the image - doubling the resolution quadruples the file size. As a general rule, for most bi-tonal applications, with the exception of ICR, a resolution of 200 dpi is quite adequate. The resolution required by most ICR packages is 300 dpi.

When choosing a scanner the most important considerations are paper handling, image quality and speed. The thickness, sizes, edges and surface finish of your documents affect paper handling, and there are a variety of mechanisms available to suit different document combinations. These range from Automatic Document Feeders with capacities of up to 1,000 pages and advanced double feed detection to flatbed units for fragile documents or books.

Any scanner will give a good crisp image from a clean black and white original but real documents, such as forms, invoices and correspondence, which feature coloured backgrounds, text ranging from dot matrix printers to handprint in a variety of colours and effects, like highlighter pens, require more sophisticated technology. “Perfect Page with iThresholding” from Kodak, “Virtual ReScan (VRS)” from Kofax, are designed to make scanning such documents easy by automatically adjusting the contrast and thresholds as required. These technologies also automatically de-skew the image of any document that was scanned slightly skewed and then crop to the size of the original paper document.

In the early document management systems all images were captured as a bitonal image (black & white) but modern systems now offer colour as it is easier for the user to recognise an image that looks like the original paper document. Nearly all scanners today are colour capable and are available across the price and performance range from all of the leading manufacturers.

Why is it important to consider scanning resolutions? Probably the key reason to scan at a lower resolution is the throughput of the scanner, as scanning at higher resolutions will slow the speed of the scanner. Most manufacturers will quote throughput speeds using an A4 document at 200dpi (dots per inch) in portrait mode, although some will quote A4 at 200 dpi using landscape mode, which will produce a higher hroughput (pages per minute). The price of storage has been reducing year on year so the cost of storing the larger files produced by colour scanning is becoming much less of an issue. The increased capacity in network bandwidths means that moving these images around the network to the user is also much less of an issue, the same is true of retrieving via the internet although both are dependent on the volume of retrievals at peak times. Storage overheads are dependent on the resolution of the image - doubling the resolution quadruples the file size. Most automatic data capture packages recommend a resolution of 300 dpi to get good accuracy, but if the images are for visual reference only this can be dropped to 200 dpi for bitonal images or 150 for colour.

You also need to consider the durability of the scanner. Each product has a duty cycle that indicates the maximum daily volume that it is designed to process. This is calculated from the total number of scans that the manufacturer designed the scanner to achieve during the equipment life and then divided into a volume per day. Which means that scanners will often perform well above the daily throughput but constantly doing so will severely shorten the equipment life. There are a range of maintenance options designed for all requirements; from ad-hoc scanning to mission critical capture. If you have the equipment covered under maintenance then some service providers will charge a surcharge for scanners being operated well above the specified daily throughput. Most units are connected to a Windows PC through industry standard USB or Firewire connectors or by dedicated high performance SCSI boards designed to extract the most from your scanner. There are however options available to allow scanners to be connected straight into a network without a PC for departmental scanning. Best of Breed scanners from Böwe Bell+Howell, Canon, Fujitsu, Kleindienst, Kodak, Panasonic, Visioneer & Xerox are all available from Headway Technology Group.

Once the appropriate hardware has been selected you will need some software to control the scanner. Scanning applications provide different levels of functionality while maintaining full use of the scanner’s capabilities and performance. Each is designed to make the capture process quick and reliable, resulting with high quality images. Optional index metadata can also be associated with the images. If you are unsure what software to use to drive the scanners then give us a call and we will be glad to advise you on all the options available from our partners.