What is the correct resolution to use when scanning documents?

What is the correct resolution for document scanning?  Today we’ll be focusing on the basics of scanning resolution and the optimum resolution when scanning for OCR (optical character recognition) and  barcode reading software.

The basics about scanning resolution and dots per inch (DPI).

  • When you scan an image, the camera on the scanner recognises the information in the span or area of 1 inch (that’s 2.54 centimetres to all of you working in metric).
  • DPI, translates as dots per inch, the number of points the scanner’s camera can recognise in that space.  The average scanner normally captures scans at 200 DPI (here’s an illustration for you).
  • dots per inch What is the correct resolution to use when scanning documents?The higher the resolution the more dots per inch and detail captured.
  • The quality captured at 200 dpi  is much better on a high quality scanner compared to the same resolution on a no frills scanner.
  • If you haven’t got the right equipment, turn to a scanning bureau like Cleardata, who have invested in the latest Kodak technology.

Scanning for Barcode Reading and OCR (Optical Character Recognition) Software

Before you start your scanning job, you need to set up a test on a sample of the images, to make sure you get the best results for your OCR or Barcode Reading Software.

These types of software can often confuse characters and provide inaccurate results. This can occur if your documents have lots of noise around the text, caused by photocopying, old documents, crumpled paper and unclean messy images.

Before running each job, Cleardata’s scanning team always tests every combination on the scanners to maximise performance, quality and accuracy.  These tests include trying various scanners, resolutions and settings and outputting the information to the OCR or barcode software, to gauge the best results for the job.

For example, when scanning for OCR or barcode, usually it’s a good idea to scan at 300 dpi. But, if you have unclean images it’s sometimes better to scan at a lower resolution e.g. 200 dpi.  This stops the scanner picking up too much detail and confusing the software and can ultimately provide better OCR results.

Cleardata’s scanning bureau uses highly sophisticated OCR software, with two to three built in OCR engines.  When each of these are applied it provides  the best quality capture results. This software is becoming increasingly advanced and is now able to recognise strings of text within documents, enabling sorting and classification by document type.

I hope you’ve found this useful, Cleardata provides professional document scanning services throughout the UK, for further information visit www.ukdocumentscanningservices.co.uk or call 0800 046 8081.