A Performance Analysis System for the Sport of Bowling

impacts. By looking at the "signature" of the impacts, it might be possible for the
MASTER application to utilize the impact information at the pins to discern whether or
not the ball hit the pocket. It might also be possible to discriminate between the first and
second balls of a frame by looking at the impact signatures of consecutive waveforms.
Light Level
140
120
100
80
60
Impact
(Head Pin)
Impact
(5 Pin)
Impact
(3 Pin)
Impact
(9 Pin)
40
20
0
2450
2500 2550 2600 2650 2700 2750 2800 2850
Milliseconds (since Release)
Figure 2-8: Raw Data Impact Region (800 ms)
2.8.3 Waveform Discrimination and Validation
Correct operation of this function is critical for proper and convenient operation of the
module. The discrimination routine implemented in this version of the module is quite
simplistic, and is based on observations of waveforms from just a single individual. In
that regard, the routine served its purpose, but it does have some inherent limitations.
Figure 2-9 shows the first 800 msecs following release of the ball. The module must
determine, within the first 533 msecs after release, whether to continue recording the
waveform, or to switch to detecting the COMM wand. With the limited scratch pad space
available (72 samples worth) for the module to make this decision, it is possible for the
routine to "misfire". Since the author generates about 420 rpms (7 rps) at release, the
routine can detect three revolutions in the validation time of 533 msecs, causing it to
decide that the ball is, in fact, rolling down the lane.
However, when executing certain spare shots, many bowlers release the ball with as little
rotation as possible in order to "flatten" the ball's hook. In this case, the module reaches
the end of the scratch pad before the discrimination routine has determined that the ball
is, in fact, rolling down the lane. The discrimination routine decides that the waveform is
invalid, and switches to detecting the COMM wand.
The waveform in Figure 2-10 was captured using the module's TEST mode, and displays
a waveform from just such a spare conversion (10-pin). This waveform resulted from the
ball rolling down the lane, but the first 600 msecs do not conform to the current definition
for a "valid" waveform in the module's embedded software.
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