Information Technology Reference
In-Depth Information
Fig. 2.6
The Anoto pattern. Left: Enlarged view of a document that contains the pattern. Right:
Highly enlarged schematic view of a 6x6 grid of points of the Anoto pattern (illustration copyright
Anoto)
Unfortunately, it is not end-users who can decide in a given situation whether the pen
should temporally store the data or stream to a nearby device. Instead the designer of
the application has to select beforehand which of the modes to use. This is necessary
because two different types of Anoto pattern, which have to be licensed separately,
enable either batch processing or streaming, but not both of them.
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Anoto Pattern
The positional information is encoded directly on the paper sheets
with a patented two-dimensional dot pattern (Fig. 2.6). The pattern is only slightly
visible to the human eye, making the print product appear slightly gray. Each dot
has a position on an imaginary grid which overlays the page. By slightly displacing
each dot in one of the four directions, a single dot encodes 2 bit of data. Each 6x6
matrix of dots encodes a unique position in the Anoto coordinate space. This gives
not only the position on a page, but also allows for distinguishing between different
pages.
The Anoto pattern can be printed on paper products with various printing tech-
niques, including offset, laser and inkjet printing. Printing is unproblematic if the
dot pattern is to be printed on empty sheets of paper that do not contain any other
printed contents. In this case, most desktop laser printers can be used, and also many
inkjet printers yield acceptable results. Things get more complicated if the page con-
tains printed contents on which the Anoto pattern is overlaid. The problem here is
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To our knowledge the only exception is the Nokia SU-1B pen, now discontinued, for which
a firmware patch exists that enables switching between batch processing and streaming on non-
streaming pattern. This pen is used in many research prototypes.
