Shinya Ito, RPT, MS of Health Science, Yutaka Tomita, Prof., Dr. Eng., Dr. Med. Sci,
Shigeo Tanabe, Ass. Prof., Dr. Eng
Jpn J Compr Rehabil Sci 4: 80-83, 2013
Purpose: Three-dimensional analyses of the foot and
lower leg have been restricted to large-scale research
facilities, since such analyses require a large
experimental area and expensive measurement
systems. Therefore, we developed a new threedimensional
method of analyzing still pictures using
commercially available digital cameras, and applied it
to clinical use.
Methods: We used three digital cameras. One was set
6 m behind the subject, while the other two were
placed at 45 degrees to the right and left sides of the
first camera, each the same distance from the subject.
We used a plaster model of a lower leg and foot, on
which several markers were mounted. The positions of
the three-dimensional coordinates of the markers were
computed by triangulation from the pictures taken
with the three cameras, and the accuracy was verified.
Results: The average reading error was 0.6 mm, and
the average and maximum repetition errors were 1.3
mm and 1.6 mm, respectively. Comparison with direct
evaluation was found to be 2.3% at maximum. These
results showed that the method is highly reliable.
Conclusion: Although a three-dimensional analysis
using this method has the limitation of still picture
analysis, it may be useful in many clinical applications
because it requires only inexpensive apparatus and a
small experimental area.
Key words: foot-lower leg alignment, three-dimensional analysis, digital camera, accuracy