Augmented Reality - ARToolkit Patternmaker
Goal
To automatically create large numbers of target patterns for the ARToolkit.
Approach
The ARToolkit normally requires custom drawn target patterns that are
hand trained using the toolkit and a camera. We want the capability of
generating large numbers of target patterns and training them
automatically. Furthermore, we want the patterns to be as clear as
possible to provide the highest performance recognition in the
toolkit.
Participants
Results
We have created the patternMaker program, which generates grids of
black and white squares. The restriction is that the grids cannot be
rotationally symmetric with itself or other grids in the group, else
the ARToolkit won't be able to extract orientation from the target
pattern. The training files are automatically generated from the
patterns.
There are two ways to use this release:
- We have provided 100 4x4 distinct checkerboard patterns to print
as targets, and the associated training files to read into your
ARToolkit application. These example files should be adequate for most
uses.
- The source code potentially can be used to generate thousands of
distinct targets and their associated training files
automatically. The source code can easily create patterns for
different n x n checkerboards.
Compared to the sample patterns provided with the ARToolkit, we have
found that our patterns can be recognized at much greater distances or
are much more stable when close. In some sense, the large black and
white squares are optimal targets. We have used a 4x4 target because
the ARToolkit uses a 16x16 grid internally, and the 4x4 target
maps more cleanly than a 3x3 pattern does even though the 3x3 should
be visible at larger distances. Modifying the ARToolkit should make
other pattern sizes more effective in the future.
Download
The example patterns and support patternMaker software can be downloaded at our download page.
Support
This project is supported by the NSF STC for Computer Graphics and
Visualization and collaborative NSF/NIH projects with the Scripps
Research Institute and the University of Washington. The ARToolkit is
publicly available from the University of Washington.
Last update: July 5, 2002
