Slide 8. Device Categories. ( This slide was photographed in the original presentation)
The companies included in the comparison testing are
pictorially illustrated in the slide below.:
In the present report, each company was ranked
according to the results. The company with the best results on a particular
parameter, received 5 points, the next position received 4 points, and so on.
The company with the worse result for this parameter received only 1 point. (There were 7
different company products that were tested. Only five of the seven were able to produce
The purpose of the present article is to demonstrate
the superiority of the APAS system over all the other systems. Overall, the
APAS system out performed the other systems by a large margin.
Ariel Dynamics, Inc. with their APAS system
Motion Analysis Corporation with their HiRes System
Peak Performance Inc. with their Motus system
Qualisys with their ProReflex system
Vicon's with their 370 system
Elite (Could not calculate adequate results and was not
included in this article)
6D Technology (Produced too many errors due to magnetic
interference and was not included in this article. A summary was presented at the
conference and is shown in the slide below.)
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Slide 10. Marker Switching occurred with the Peak and Vicon Systems.
Slide 10 illustrates the serious problem that Peak and
Vicon companies had with switching points. Once the points were switched, it was
impossible to correct them. In the case of the APAS system, marker switching can
never occur since the detection algorithm can maintain the marker identification at all
In the case of Peak and Vicon, markers crossed paths.
The data presented at the conference reported only a subset of the data in which
paths were correctly identified and this information was used for the analysis. In this
case, the Peak and Vicon received only 1 point each while all the other companies that did
not have this serious defect in their system received 3 points. The confusion of
markers is considered as the most serious error in Movement Analysis Systems.
Some companies such as Elite and Codex produced
so many errors that the researcher of this study choose not to include them at all.
In other cases, such as with the Peak and the Vicon companies, errors were very large when
detection points were switched around, so the researcher of this experiment decided
to choose only the good measurements. Quoting the original report: "The
Peak Motus and the Vicon 370 systems were unable to correct switching paths at the 0-cm
and 1-cm separation distances, despite repeated attempts to adjust tracking
parameters". It could be argued that this biased the experiment
to some degree by making the Vicon and the Peak companies score higher then they would
otherwise if all the data point had been considered as was the case with the Ariel and the
Motion Analysis systems.
Slide 9 illustrates the Skill 6-D Summary as was
presented at the conference. As one can see, this technology is still new and did not meet
the required standards. This technology depends on the subject being hard wired to the
sensors and is extremely sensitive to interference. This equipment does not allow data
collection on the field and movement is limited to an area of approximately 3M only.
Therefore, the present report did not include this technology in the rating.
Slide 9. Skill 6-D Summary. (Slide was photographed in the original presentation)