A Digital Stereo Microscope Platform for Microsurgery Training - Technologies and Applications of Artificial Intelligence - page 305

A representative dexterity measure is computed for the methods based on the his-
togram and is shown in Fig.7. In the case of Dr, the economy of path length is directly
reflected. It is also a measure of accuracy as well as control.

4 Results and Discussion

The quality of motion has three components, the tremor content in the motion in com-
parison with the voluntary motion, the correctness of the motion or the lack of thereof
and the smoothness of the motion. The tremor content may be assessed by using the
motion produced by the tremor and by the voluntary motion. The correctness is ana-
lyzed by verifying the motion produced by the trainee and the intended motion.
The dexterity measures of the previous section considered many of these aspects.
One method is combine the values obtained through the assessment by each of the
methods and create a combined value of dexterity. However, the range of values of
the dexterity measures are varied that a meaningful combination is difficult. Another
approach is to assign grades or votes by each dexterity measure which can be com-
bined.
A third approach is to combine the elements of the measures into a single measure.
We present a single measure called the quality of the procedure which considers the
number of movements and classify them as smooth movement or jerky movement.
The smoothness of other motion may be assessed by computing the Jerk (the rate
of change of acceleration) in the segmented movements. A ratio of the movements
where Jerk is present to that where Jerk is not present can indicate the smoothness of
the movement.

Dexterity Based on Movement Types

90%

80%

70%

60%

50%

40%

30%

20%

10%

0%

0 5 10 15 20 25 30 35 40 45

Experiment ID

Fig. 8. Dexterity assessment based on the type of movement