A Performance Analysis System for the Sport of Bowling

2.9.5 Module Training
Due to variations in bowler style and bowling
equipment, and with inherent variations in the
ambient background light levels at various bowling
establishments, it will probably be necessary to
"train" the module for a given bowler, and for a
given establishment. This can be easily
accommodated at the beginning of each session of
bowling.
The MASTER application would issue a command to
the module to take samples without data
compression. This data, collected from several
"training" shots would then be uploaded to the
MASTER program, which would scan the data and
come up with the best-fit translation table, and
download the table to the module. The module
would then use these values in its data compression
routines. If the module was not trained, it could use
the last translation table downloaded to it as a
default.
The MASTER program could also determine the
average ball speed of the bowler and use this
information to decide whether there was enough
room to store uncompressed data (since the amount
of space used is dependent on the waveform sample
time), or to use the data compression function.
Stored
Nibble
Value
Actual Sample Value
(0) Range
Bit
(1) Range
Bit
0x0 < 5 28-29
0x1 5-8 30-31
0x2 9-12 32-33
0x3 13-14 34-35
0x4 15-16 36-37
0x5 17 38-39
0x6 18 40-41
0x7 19 42-43
0x8 20 44-45
0x9 21 46-49
0xA 22 50-54
0xB 23 55-59
0xC 24 60-79
0xD 25 80-99
0xE 26 100-127
0xF 27 >127
Figure 2-13: Data Compression
Translation Table
2.9.6 Adjustable Sampling Parameters
Preliminary analysis of the data collected revealed that some type of digital filtering is
required in order to extract useful data from the captured waveform. However, the 120
Hz sampling rate may not be high enough to accurately achieve the desired resolution in
angular velocity (rpms). The 120 Hz rate is the minimum acceptable, but 240 Hz, or
even 480 Hz, may be required. Of course, higher sampling rates increase the data storage
requirements, and require faster EEPROM write times. Ramtron makes an appropriate
density ferroelectric serial EEPROM with a write time equivalent to the data bus speed
that fits the application, although the cost-per-bit is ∼50% higher than that for standard
serial EEPROMs [22].
The sampling rate could be adjusted based on the rate of rotation the bowler applies to the
ball and on the velocity that the bowler throws the ball. The higher the rate of rotation,
and/or the velocity, the higher the sampling rate should be. But with a higher ball speed,
less time is required to sample the full waveform, so there should be some offset between
the increased sample rate and the reduced sample time.
Another option is to interpolate between 120 Hz samples based on the rate of change of
the sample values surrounding the values to be interpolated. This interpolation would be
handled by the MASTER application.
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