Game Development Reference
In-Depth Information
Understanding fiducial markers
A graphic marker is both the popular metaphor for AR technology (since people as-
sociate it with some mysterious symbols printed on paper) and its weakness (since
it means that additional equipment is required for AR applications to operate). The
need for additional equipment to operate AR applications is often considered their dis-
advantage, and hinders the popularity of AR games because players can sometimes
be lazy and don't want to print out the markers. Nevertheless, the graphic fiducials
have very important advantages: first of all, they require less calculation power, and
secondly, they are pretty accurate because fiducials are friendly for computer-vision
systems and very accessible to perform digital image scanning.
Engineers have tried to "teach" machines to read some printed data by using optical
sensors since the end of 1940s. However, the machines were not good at learning
human alphabets because doing so would take a long time. Furthermore, the level of
errors could be very high. Thus, a new paradigm was invented, that is, writing sys-
tems for machines; machine-readable mediums were introduced. Joseph Woodland
and Bernard Silver patented the very first barcode in 1952. It looked like a section of a
tree with annual growth rings. For the human eye, such an image was a total abstrac-
tion, but not for a machine. So, from the very beginning, machine-readable solutions
were totally different from any traditional ways to provide information. The data was
coded, so humans were not able to read complete information without an automatic
translator.
The title of the topic encoded in various data codes. All of them were created with a free barcode gen-
erator (http://www.racoindustries.com/barcodegenerator/)
Traditional one-dimensional, rectangular barcodes were standardized and became
commercially routine in the 1970s. Since then, barcodes have turned into a symbol
of communication between industrial machines and the physical world. However, the
barcode was not the only one of its kind. Each industry had its own requirements and
tasks, so some alternative solutions were introduced as well. First of all, the optical
message got a second dimension, so it could store not only a linear array of informa-
tion, but a matrix of data.
