A Performance Analysis System for the Sport of Bowling

3.7 FUTURE WORK
The MASTER application, in its current incarnation, has served solely as a research tool.
It facilitates rapid assessment of the SMARTDOT module's performance, and enables the
review and archival of previously collected data. As the MASTER analysis algorithms
have been developed and modified, this version of the MASTER application has made it
possible to recall previous raw data waveforms and observe the effects of the changes to
the algorithms.
3.7.1 Algorithms
The analysis algorithms are still evolving. Various concerns and problems have been
presented over the course of the paper, and several of these stand out.
• Filtering the Raw Data Waveform: This is the most important step in the entire
analysis process. The basis for the analysis algorithms is that the waveform is
representative of the angular position of a single point on the ball. As the ball
rolls down the lane, that point transcribes a sinusoidal path that the SMARTDOT
module captures, and that the MASTER unit analyzes to recover the action of the
ball. If this waveform cannot be recovered "cleanly", the analysis will be flawed.
A simple FFT function was used to find the spectrum, and an adaptive filter was
used to filter the waveform. Although the spectrum of the waveform reveals a
great deal of information, the major focus of interest is the manner in which the
frequency changes over time, which an FFT does not reveal. Therefore, further
investigation needs to be performed into more advanced digital processing
techniques, more specifically into wavelet theory, which will allow the MASTER
algorithms to characterize the timing of the frequencies in the waveform.
• Curve Fitting: Due to the Doppler effect observed in the raw angular velocity
waveform, it has not been possible to directly recover the instantaneous angular
velocity of the ball from the raw data. Therefore, a least-squares curve-fitting
scheme was used to approximate the true shape of the angular velocity waveform.
However, this scheme does not include facts about the nature of the waveform
that are known to be true, i.e., that it is monotonically increasing, at least until
rollout occurs. A more refined method must be identified that takes into account
the specific nature of this problem.
• Friction: Throughout the analysis, an assumption has been maintained that no
energy is lost due to friction. Actually, the energy lost is relatively small, but not
negligible. Since the linear velocity is derived from the change in angular
momentum, any portion of the linear momentum that is not transferred to angular
momentum causes the resultant linear velocity calculation to be too low.
It appears to be possible to recover the actual frictional force or, at the very least,
to place upper and lower bounds upon it. Since the ball is always revolving
slower than it is traveling, and the number of revolutions of the ball is known, the
total distance the ball would have traveled had it not been skidding during those
revolutions can be calculated. This distance will always be less than the distance
the ball actually traveled (nominally 60 feet).
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