optical character recognition (OCR) use of technology to distinguish handwritten or printed text characters inside digital images of physical documents, such as a scanned paper document. An optical scanner is a device used to read an image, convert it into a set of 0 and 1 and store this in computer memory. This is known as bit map. Hence, optical scanner converts an image to an equivalent bit map representation. If we have input source as text document then bit map representation of text document have two problems.
The OCR technology is used to overcome these problems. if our scanner is equipped with OCR software, then it can convert bit map images of characters to equivalent ASCII codes i.e. the scanner first converts the bit map image of the document and then OCR software translates the bit map image into ASCII Text, which can later be processed.