The full form of OCR is Optical Character Reader . The optical character reader can not only spot but also distinguish between different colors. OCR generates electrical signals in some of the letters according to the structure of that letter. In OCR, the electrical signal of each letter is already stored in the computer - OCR can understand which letter is being read and store it in the computer. OCR is used to read letter pin codes , electric bills , life insurance premiums , netish etc.