| Scanner | ||
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A scanner is a device used to digitise graphics. To scan an object is to use a scanner to produce data. Hand-held scanners may be passed over a picture. Flat-bed scanners remain still while the picture is scanned. As well as digitising pictures, scanners may be used for capturing text from documents (see OCR).
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To digitise
data means to convert it to a digital
form (ie numbers).
Each pixel is stored as a number in a bitmap. The resolution of a scanner is a measure of the number of pixels it uses. Higher resolutions mean clearer pictures. High resolution bitmaps require a lot of storage space. |
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| Exercise : Scanner | ||
| A scanner will a picture - change it into
. Some scanners are hand-held but larger flat-bed scanners are more
common.
Each of a picture is stored as a number. resolution pictures use more pixels and are clearer but take up more .
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| (Green indicates success) | ||
