'Optical mark recognition' is the process of capturing data by contrasting reflectivity at predetermined positions on a page. By shining a beam of light onto the paper the scanner is able to detect a marked area because it reflects less light than the blank areas of the paper. Some OMR devices use forms which are preprinted onto 'Transoptic' paper and measure the amount of light which passes through the paper, thus a mark on either side of the paper will reduce the amount of light passing through the paper.
It is generally distinguished from optical character recognition by the fact that a recognition engine is not required. That is, the marks are constructed in such a way that there is little chance of not reading the marks correctly. This does require the image to have high contrast and an easily-recognizable or irrelevant shape.
One of the most familiar applications of optical mark recognition is the use of #2 (HB in Europe) pencil bubble optical answer sheets in multiple choice question examinations. Students mark their answers, or other personal information, by darkening circles marked on a pre-printed sheet. Afterwards the sheet is automatically graded by a scanning machine. In most European countries, a horizontal or vertical 'tick' in a rectangular 'lozenge' is the most commonly used type of OMR form, the most familiar application being the UK National lottery form. Lozenge marks are a later technology and have the advantage of being easier to mark and easier to erase. The large 'bubble' marks are legacy technology from the very early OMR machines that were so insensitive a large mark was required for reliability. In most Asian countries, a special marker is used to fill in an optical answer sheet. Students, likewise mark answers or other information via darkening circles marked on a pre-printed sheet. Then the sheet is automatically graded by a scanning machine.
Another example of OMR is the recognition of scannable bar codes.
Recent improvements in OMR have led to various kinds of two dimensional bar codes called matrix codes. For example, United Parcel Service (UPS) now prints a two dimensional bar code on every package. The code is stored in a grid of black-and-white hexagons surrounding a bullseye-shaped finder pattern. These images include error-checking data, allowing for extremely accurate scanning even when the pattern is damaged.
Most of today's OMR applications work from mechanically generated images like bar codes. A smaller but still significant number of applications involve people filling in specialized forms. These forms are optimized for computer scanning, with careful registration in the printing, and careful design so that ambiguity is reduced to the minimum possible. Due to its extremely low error rate, low cost and ease-of-use, OMR is a popular method of tallying votes.
OMR is now used as an input device for data entry. Two early forms of OMR are paper tape and punch cards which use actual holes punched into the medium instead of pencil filled circles on the medium. Paper tape was used as early as 1857 as an input device for telegraph (Yurcik, n.d). Punch cards were created in 1890 and were used as input devices for computers. The use of punch cards declined greatly in the early 1970’s with the introduction of personal computers (Palmer, 1989). With modern OMR, where the presence of a pencil filled in bubble is recognized, the recognition is done via an optical scanner.
The first mark sense scanner was the IBM 805 Test Scoring Machine; this read marks by sensing the electrical conductivity of graphite pencil lead using pairs of wire brushes that scanned the page. In the 1930's, Richard Warren at IBM experimented with optical mark sense systems for test scoring, as documented in US Patents 2,150,256 (filed in 1932, granted in 1939) and 2,010,653 (filed in 1933, granted in 1935). The first successful optical mark-sense scanner was developed by Everett Franklin Lindquist as documented in US Patent 3,050,248 (filed in 1955, granted in 1962). Lindquist had developed numerous standardized educational tests, and needed a better test scoring machine than the then-standard IBM 805. The rights to Lindquist's patents were held by the Measurement Research Center until 1968, when the University of Iowa sold the operation to Westinghouse Corporation. Westinghouse Learning Corporation was acquired by National Computer Systems in 1983; in 2000, Pearson Education acquired NCS. IN 2008, NCS Pearson was acquired by Scantron.
During the same period, IBM also developed a successful optical mark-sense test-scoring machine, as documented in US Patent 2,944,734 (filed in 1957, granted in 1960). IBM commercialized this as the IBM 1230 Optical mark scoring reader in 1962. This and a variety of related machines allowed IBM to migrate a wide variety of applications developed for its mark sense machines to the new optical technology. These applications included a variety of inventory management and trouble reporting forms, most of which had the dimensions of a standard punched card.
While the other players in the educational testing arena focused on selling scanning services, Scantron Corporation, founded in 1972 , had a different model, distribute inexpensive scanners to schools and make profits from selling the test forms As a result, many people came to think of all mark-sense forms (whether optically sensed or not) as scantron forms, although the term remains a trademark. Scantron operates as a subsidiary of M&F Worldwide(MFW) and provides testing and assessment systems and services and data collection and analysis services to educational institutions, businesses and government.
Like Scantron, Chatsworth Data Corporation is a seller of scannerswith annual revenues of over $9 million in annual revenues, compared to Scantron's $250 million in annual revenues. Founded in 1971 , Chatsworth has always focused on selling the scanners themselves, mostly as OEM products incorporated into systems developed by others.
OMR has been used in many situations as mentioned below. The use of OMR in inventory systems was a transition between punch cards and bar codes and is not used as much for this purpose (Palmer, 1989). OMR is still used extensively for surveys and testing though.
OMR can also be used for personal use. There are all-in-one printers in the market that will print the photos the user selects by filling in the bubbles for size and paper selection on an index sheet that has been printed. Once the sheet has been filled in, the individual places the sheet on the scanner to be scanned and the printer will print the photos according to the marks that were indicated (M. Meek, personal communication, Feb 11, 2006).
For the most part OMR provides a fast, accurate way to collect and input data, however it is not suited for everyone’s needs.
As a result of the widespread adoption and ease of use of OMR, standardized examinations consist primarily of multiple-choice questions, changing the nature of what is being tested.