An optical character recognition device, often abbreviated as OCR, is able to recognize text that is printed in a specific type font. Early OCR equipment could only read one type face (like this one) in dot matrix form. Scanners are a form of OCR family that can read almost any type font and their accuracy depends in large part on the text or recognition software used. The device converts light—an analog continuous wave form—into digital binary bits of zero and one [0,1] which is a discrete wave form. To accomplish this, scanners use electronic components such as charge-coupled devices (CCD), a diode that is light sensitive when electrically charged, or photomultiplier tubes (PMT), a light sensitive tube that detects light at any intensity by amplifying it. PMTs are usually associated with drum scanners. Some examples of scanners are as follows.
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