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Ball Spin Setup
Selecting the Ball Spin Detection method
There are currently 3 methods of ball spin detection:
1.
Spin calculated using balls without markings
The spin rate is then calculated from ball and club data.
Note that as long as the shot is reasonably straight,
the difference between measured and calculated ball spin is mostly marginal
2.
Using balls with spin dots on them
The spin rate is then measured
The advantage of using spin dot balls compared to using the ball logo or line,
is that you don't have to bend down to align the ball logo or line to the camera.
3.
Using balls with a line or strong black logo
This method is mostly very accurate but requires the user to bend down to align the ball logo or line to the camera.
4.
Ball dimple method
(not yet available)
i.e. using balls without any markings and relying on ball dimple patterns to determine spin rate.
This method is currently in development but we cannot guarantee when this development will be completed.
VisTrak SCX Ball Spin Detection
If you prefer measured ball spin instead of calculated ball spin, then spin dot balls will be required
The above image (from a customer shot video) shows the issue with longer exposure times
and out of focus lenses when attempting to detect ball spin dot markings.
Exposure times need to be under 150 us to reduce motion blur caused by the ball traveling at high speeds.
Nether-the-less, if increasing the Ball Spot GS (gray scale) to 200,
then even out of focus and blurry ball dots can be detected.
Today's CP version also features improved ball spin frame detection by attempting to find 2 adjacent
ball images that have at least 3 dots on them instead of just 2.
Note that only well defined and spaced spin dot balls or balls with a strong logo can be used ( as shown above).
Note that camera exposure time (i.e. shutter speed) has to be set at or below 200 micro seconds and frame set to 1500 fps.
Note that the "Ball line/Spot GS" (Gray Scale) may ( depending on your lighting )
have to be adjusted up or down in order to detect the ball spin dot or ball logo.
New Ball Spin detection using the ball logo
for overhead SCX and Eagle systems
You can now select the option "Spin line / Logo on ball" to measure ball spin for overhead camera systems (i.e. SCX and Eagle).
As the logo will not always be visible in the frames, the system now automatically scans for 2 adjacent fames showing the ball logo
in all the 16 ball speed frames.
VisTrak EVi Ball Spin Detection
Ball Spin Detection from the Side camera
Using the ball logo or line
When the EVi or LX Vcam is placed close to the ball (i.e within 12 to 16 inches),
the camera detects ball spin rate using either the ball logo or ball spin dots.
Using balls with spin dots on them
The Vcam with EVi and LX systems view the ball from the side.
Rotation - when using spin dot balls - is calculated around the center of the ball between frames
Note that the "Ball line/Spot GS" (Gray Scale) may have to be adjusted up or down in order to detect the spin dot or ball logo/line.
EV Ball Spin Detection from the overhead camera
Ball spin can also be measured from the EV overhead camera
Rotation and spin axis is calculated by comparing x and y spin dot deviation positions between frames
Ball spin for Putts
Measured ball spin when putting is done without the requirement to use ball markings.
Spin Dot / Ball Logo Detection issues
In order to detect the spin dots on the ball or ball logos, the images should be sharp and clear.
In order to achieve this, the camera exposure time has to be fast (i.e. around 150 us) with bright lighting.
If - as in the above image - the exposure time is too long (i.e. 300 us plus) then image blur will occur and the dots will appear faint.
Adjusting the "Ball Line/Spot GS" (gray scale) to a very high level (i.e. 200) can help though.
Click above to read more about ball spin detectionn theory...