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Bridging the Gap!. Great Barton Computer Club. An introduction to the use of a scanner with your computer. Peter Brindley. Scanning Documents and OCR. What is a scanner anyway?.

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Presentation Transcript
what is a scanner anyway
What is a scanner anyway?
  • I suppose that we can say that a scanner is one of the most versatile pieces of hardware that can be attached to your machine. Often the function is included within an All-in-One printer.
  • We have all used a photo-copier – merely a scanner attached to a printer – in one box!
  • A relatively cheap piece of hardware.
  • Your scanner will transfer an image file to a computer instead of printing it automatically.
what happens inside a scanner
What happens inside a scanner?
  • Actually very basic with few moving parts.
  • The scanner has a sensor that moves across the document and is allied to a powerful light source.
  • As the sensor moves past the original, each cell sends a level of electrical current corresponding to one dot (a pixel) of the reflected light from the material.
  • The scanners brain records these signals as a digital picture of one line of dots.
what happens continued
What happens (continued)?
  • The data is sent to the PC.
  • The sensor (or the document in the case of a sheet feed scanner) advances one line and the process begins again creating the second line of data.
  • This can, perhaps, be described as a process that takes a picture of each line of your document (or picture) and then pastes them together to form the whole computer file.
output of the scanner
Output of the scanner?
  • The image that is taken from a picture or a text document (sometimes both intermixed) is transferred to the computer.
  • A picture is (typically) transferred in the form of a JPEG ( .jpg ) file. This means that it can be stored and manipulated in the same way that you might work on a photograph downloaded from your camera or received from a colleague.
text documents
Text documents
  • Text documents are stored in a number of formats and these will be particular to your software. It is possible to scan a document in to Microsoft Word and it will therefore be a Word Document (.doc) but it will be an image document only and whilst it will open in Microsoft Word you will not be able to edit it.
  • An increasingly common 'file type' for these documents is Portable Document File (.pdf).
size can matter
Size can Matter!
  • The scanner is routinely used to store documents (destroy the original), amend and alter documents/photographs and send items as attachments or faxes.
  • If sent as attachments we do need to consider the file size. Not every one has broadband and three weeks to download a picture of 'little Jimmy'.
  • This can be altered by considering the physical size of the document, the DPI (dots per inch) and file type.
types of scanner 1
Types of scanner. 1
  • The office photocopier. A scanner, computer and printer in a box!
types of scanner 2
Types of Scanner 2
  • 'Flatbed' scanner. The top lifts and the sensor moves underneath the document that is held motionless. Buttons select copy, scan, email,fax etc.
types of scanner 3
Types of Scanner 3
  • Sheet fed scanner - the document feeder passes the paper over a fixed scan head. Paper is moving and the quality is less, but ideal for multiple copies.
  • Machine shown is the one I have with me. It is an All-in-One with built in sheet feed.
types of scanner 4
Types of Scanner 4
  • This is an artist's impression of a simple sheet fed scanner.
  • Documents need to be pristine with no staples, clips etc.
types of scanner 6

There are other types of scanner and these are usually of a specialist nature. Differing types of Automatic Document Feed (ADF) can be used to deal with photographs, photo negatives, business cards etc.

A pen scanner can be used to capture single lines of text. This may be particularly useful with a laptop and OCR (Optical Character Reading) to read text into an editable word processing application.

Types of Scanner 6
optical character reading software 1
Optical Character Reading Software 1
  • Many differing software packages available.
  • Examples are I.R.I.S., Textbridge and Omnipage.
  • Each have their own attributes and tell you that they are the best!
  • Probably the more expensive are the best as they are written for commercial applications.
  • Scanner software often includes basic OCR software (A 'lite' version) and they will try to encourage an upgrade in exchange for cash!
optical character reading 2
Optical Character Reading 2
  • Remember that a simple scan image is not editable.
  • OCR works best with simple typed text and a mixture of text, graphics, photographs and formatting, will test the OCR software to the full.
  • The better quality the scan the better the OCR result. K.i.v. What I said about flatbed and sheetfed scanners.
connection to the computer
Connection to the computer
  • Just for the 'techies' amongst you the link between the computer and scanner is generally described as TWAIN or WIA. These utilise the USB ports and Windows XP can cope. Older scanners used to use things like a serial port or SCSI port. If you have one of these and they work then fine, if not then invest!
  • TWAIN is a standard interface format – TECHNOLOGY WITHOUT AN INTERESTING NAME!
basic do s and don ts
Basic do's and don'ts!
  • No heavy objects on scanner glass – obvious!
  • No staples, paperclips etc Flatten documents.
  • Use the largest possible original.
  • Care cleaning glass or sensor bar (Weekly). No liquids or sprays. Photographers lens cloth or monitor wipe (alcohol evaporates quickly).
basic do s and don ts 2
Basic do's and don'ts 2
  • Scanning requires RAM memory to be available if it is to be reasonably quick. 256MB minimum but 512MB+ even better. A scanned image may be 50MB in size!
  • If you plan to edit or change an image after scanning. Keep a copy of original and work on a copy.
  • Refer to web site of the manufacturer occasionally to update scanner drivers.
the epilogue
The epilogue!
  • That is enough for the presentation.
  • I propose to use the computer and scanners that I have with me to demonstrate some of these issues.
  • Remember that the software that I have is the software that came with my machine and may be different from the package that you have.