Optical mark recognition is the process of capturing data
from the preparation form by recognizing the reflection patterns
from the marked positions on a page. The reader or scanner is
able to detect a marked area by shining a beam of light on the
page to obtain the reflection patterns[2], [3]. One of the most
familiar applications of optical marking recognition is the use
of 2B-pencil to color the bubble on answer sheets in multiple
choice question examinations. Students mark their answers
by darkening circles marked on a pre-printed sheet. This sheet
is then automatically graded by a scanning machine.
The scanning machine, which is also known as the OMR
machine, can maintain a throughput of 1,800 to 10,000 forms
per hour. This activity can be controlled and processed by a
single machine that is more than enough for the primary and
secondary schools. Indeed, the OMR machines are not
scanners in the sense that they do not form an image of the
sheets that pass through. Instead, the OMR device simply
detects whether predefined areas are blank or have been
marked. The fact that OMRs do not form an image differentiates
them from desktop scanners that are often used to capture
and form the image. This isalso the reason why OMR machines
have the capacity to read sheets at a very high rate.