All these scanners produce two-dimensional images of subjects that are usually flat, but sometimes solid 3D scanners produce information on the three-dimensional structure of solid objects.ĭigital cameras can be used for the same purposes as dedicated scanners. Non-contact planetary scanners essentially photograph delicate books and documents. A rotary scanner, used for high-speed document scanning, is a type of drum scanner that uses a CCD array instead of a photomultiplier. Modern scanners typically use a charge-coupled device (CCD) or a contact image sensor (CIS) as the image sensor, whereas drum scanners, developed earlier and still used for the highest possible image quality, use a photomultiplier tube (PMT) as the image sensor. Mechanically driven scanners that move the document are typically used for large-format documents, where a flatbed design would be impractical. Hand-held scanners, where the device is moved by hand, have evolved from text scanning "wands" to 3D scanners used for industrial design, reverse engineering, test and measurement, orthotics, gaming and other applications.
Commonly used in offices are variations of the desktop flatbed scanner where the document is placed on a glass window for scanning. Documents or images are placed face-down beneath the cover (shown closed here).Īn image scanner-often abbreviated to just scanner-is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image.
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