a) MICR: MICR is a character recognition technology used primarily by the banking industry to facilitate the processing of cheques. The human readable characters are printed on documents using a magnetic ink. It stands for Magnetic Ink Character Recognition.
b) OMR: OMR which stands for Optical Mark Recognition is the process of gathering data with an optical scanner by measuring the reflectively of light at predetermined positions on a surface.
c) OCR: OCR stands for Optical Character Recognition. OCR is the recognition of printed or written text characters by a computer. It is the application software that allows a computer to recognize printed or written characters, e.g. letters, numbers, punctuation marks, and pictograms using an optical scanner for input. OCR is being used by libraries to digitize and preserve their holdings.
d) OBR: It stands for Optical Bar Code Reader which is used for reading bar-coded data. It scans a set of vertical bars of different width for specific data and is used to read tags. Bar code reading is done by a light pen or scanner connected to a computer.