Page "Optical mark recognition" Paragraph 6

One of the most familiar applications of optical mark recognition is the use of # 2 pencil ( HB in Europe ) 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.