Scanners

• An optical scanner can be used to scan graphical images and photographs
• Software can then be used to edit or touch up the images
• Scanners can also be used to read typed or even hand-written documents

Scanners are also used to input large volumes of data on preprinted forms such as credit card payments, where the customers account number and amount paid are printed at the bottom of the payment slip. Many banks are now using ATMs where the customer can pay in a cheque this is scanned the numbers are read via OCR and checked against data the customer types in.

Optical Mark Reading

The input document is accurately laid out. Input consists of the presence or absence of a mark in pre-determined positions on the source document. Normally the mark is a (soft) pencil or black biro line joining two dots on the document. The document is normally printed in an ink that will not be seen by the reader. Lines down the edge of the document allow the reader to determine the orientation and position of the document as it passes through.

The OMR sheets must be printed to a high specification. They cannot normally be photocopied for use because a photocopier does not reproduce the positions of the guide marks accurately. This increases the cost of the source documents.

OMR provides an easy way for users to record data where there are a limited number of possible inputs. Several thousand documents per hour can be read. OMR can be used to collect numerical data and it is also used to capture answers to multiple choice examinations. A further possible use would be collecting survey information. It has been used for collecting meter readings but is now superseded by hand held data recorders that store the meter readings in RAM.

OMR is useful for turnaround documents. That is documents that originate from the computer, are completed and then use to input further data. In the case of multiple choice answer sheets the candidate number and the centre number would be printed in OMR form on the answer sheet before being sent to the school.

Disadvantages of OMR are that creased or dirty documents cannot be read. If the user alters an entry the resultant smudging may make the document unreadable. It can only collect a limited range of responses that can be indicated in advance on the form.

An OMR would have a hopper for rejected documents that could not be read or which had entries that were not permitted - e.g. two answers to a question. These would be examined by the operator and the data then input manually.

Optical Character Recognition

Printed or even hand-written characters on the document are compared with stored character shapes. Up to 300 pages per hour can be scanned although there may be problems over distinguishing between O and 0, I and 1 unless special fonts are used.

OCR is useful for inputting large volumes of text - perhaps for later checking and editing. An example might be to input a long list of addresses that are available in printed form only.

OCR is heavily used in turnaround documents in application such as utility billing and insurance premium renewal. The bill is prepared with OCR customer identification and posted. When the customer pays the bill they return part of the original document with their payment and this is fed back into the system via an OCR reader.

As with OMR, provision must be made for collecting and inputting data from rejected documents by hand.

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