Ball Spin Detection System
Note that our camera ball spin detection cameras require that the ball has a black manufacturers logo on it and that the
ball has to be placed on the hitting mat with ball logo facing the cameras.
In addition, the ball logo may have to be marked (with a black ink marker) so that the cameras can identify one end of the logo from the other.
Add-on for CX2, CX3 or CX4 systems
Featured in CX6/F6 systems
The Bcam is a floor side mounted in camera system placed at some 5 to 7 ft away from the hitting mat
The Bcam ball spin camera system consists of a VisTrack Pro (dual IR Xenon flash units, dual HD cameras with zoom lenses), cables and software.
The ball spin detection method consists of capturing 2 images of the ball in flight shortly after club impact to the ball.
The cameras and IR flash units are triggered by a single optical sensor in the hitting mat.
Note that the Bcam system requires that your PC has two free PCIe slots for quad channel USB adapters in order to connect up 5 or 6 cameras
Note that that the Bcam is similar to a regular Launch Monitor in as much that it is side mounted and can only be used for
either a right handed player or left-handed player single time. i.e. it cannot be used for both RH and LH players during a game.
Optional cabinet casings are also available
Bcam Ball Markings
Regular golf balls without extra markings can be used with the Bcam as long as the logo is facing the camera
When using regular balls ensure that the logo is black and clearly defined.
For best results use balls like the Srixon range balls that feature large black stripes on both sides.
However, all Bcams can be supplied with special spin dot pattern balls that save the player from having to bend down and line up the ball logo or line to the cameras.
Bcam comes complete with trigger mat
Bcam ball spin detection cameras
How the Bcam measures spin
The Bcam uses IR Xenon lighting and zoom lenses to capture two frames of the ball in flight
The IR Xenon lighting is required as the camera's shutter speed has to be very fast (typically less than 10 micro seconds) to obtain freeze frame images of a ball possibly traveling in excess of 200 mph.
When the ball is hit, it will pass over a sensor in the trigger mat that will generate a trigger signal to the Bcam cameras.
Image processing measures the number of degrees the dots or logo on the ball has rotated and their side shift within the frame time window
This information is then used to calculate the spin rate and spin axis.
The above images - from the Biomechanics department of MMU - show that the ball markings will remain in view for the overhead mounted Bcam camera during the first few centimeters of flight.
Spin rate and spin axis are calculated from the number of degrees of rotation from the time the ball passes over the trigger sensor and the set camera time delay.
Spin dot balls
The unit can also be used use with our proprietary spin dot balls
Using these high quality tournament balls saves you from having to bend down and align ball logo markings to the camera.
The dots are bake printed in 6 positions on the golf balls (top, bottom, left, right, back and front) and will eliminate the requirement to manually align ball logos to the LX cameras.
12 balls are free of charge to all Bcam customers. Additional balls are $4 each.
The above shows a typical image of a spin dot ball in flight captured with the Bcam
The above image shows a composite of frames 1 & 2 as viewed from Bcam when side mounted.
Note that when the Bcam is side mounted (up to 9 feet away), the system functions exactly the same as our LX Lite launch monitor.
The main difference only being that the camera features a zoom lens and uses an IR Xenon flash instead of an LED flash.
Click above image to see the Bcam in action when floor mounted
Click above image to see the Bcam in action when overhead mounted
Detecting ball spin without markings
You may have noticed that there's a couple of golf simulator and launch monitor manufacturers on the market claiming to be able to detect ball spin without markings on the ball.
This all sounds really great of course but is it really true or is it just a marketing ploy?
In our extensive research, measuring ball spin using camera images of a ball without markings on it - at least with any real degree of accuracy - is essentially impossible, so how is it done?
We'll there are three main methods.
1. They are using the ball logo as a marking.
This method will work at least 60 percent - if not 70 percent - of the time as the chances that at least a part of the logo will be visible within the frames is far greater than there being no part of the logo being visible in the images.
For the remaining 30 to 40 percent of the time, the ball spin can be just estimated and the user will never know the difference.
Thus, as a golf simulator manufacturer using this method, you can just claim that you can detect ball spin without markings on it as it is not required to state that this detection works 100% of the time.
2. They are assuming the balls will have been used numerous times
and overtime scuff marks have developed on the ball and these will be visible in the images.
Again, this is just as much a hit and miss method as the ball logo method but using these scuff marks to make virtual markings will increase the chance of real spin detection.
3. They are detecting ball dimple patterns.
Considering that the dimple patterns on a golf ball are essentially symmetrical and that the spin axis will not be on a perfectly horizontal plane
i.e. there would be spin tilt in most shots
it would be near impossible to find an accurate match between two images of the ball after it has rotated a number of degrees in real time
4. They are just telling you they are detecting ball spin but in fact are just estimating it
We know of a number of golf simulator companies that do this to influence the potential unaware buyer into purchasing their products
In particular some manufacturers of low cost optical sensor pads are using this unscrupulous method to boost their sales by praying on the less technically minded customer.
So buyer beware: unless the product has been proven to actually measure ball spin, then don't believe a word of it
Note that all our competitors ball spin camera systems that attempt to measure ball spin
without markings on the ball require a lot of time in order to do this.
As such these systems are not real time and often require a 4 seconds or more to achieve an estimate.
i.e. there's a 4 second or more lag time between the user striking the ball and the ball launching in the game.
The ball dimple method involves selecting small areas of the ball in the first image and - through a process of rotation and image matching - attempting to find these areas again in a second image of the ball after it has rotated a number of degrees.
The above images were taken with the LX Pro 2 using Xenon flashes.
I've drawn a line to show the actual rotation as a guide but you can see it is going to be quite a challenge to pull this off. First issue is that some dimples are reflecting the flash back and appear very bright.
These have to be identified and removed from the images as they will cause problems with the matching process.
The main problem I see is that there will be so much computation involved with all the image rotations and matching that the process will not be in real time.
i.e. it would take numerous seconds for the process to complete and - in our opinion at least - still unlikely to be accurate.
Of interest - most (if not all) of the manufactures using this method offer the option to switch off this process as the lag time between striking the ball and seeing it launch in the game software can be very frustrating
So to conclude: Yes, manufacturers can legitimately claim that they measure ball spin without markings - even though - legally speaking - both logos and scuff marks are also markings -
but we very much doubt it is anywhere near 100% of the time
and as the user has no way to verify their claims, he or she will be none the wiser.
Of interest, one very well known camera based launch monitor manufacturer even admits on their own web site that if placing balls with their logos facing the cameras in the launch monitor
then the ball spin detection accuracy would be more accurate.
Such statements would strongly indicate that their ball spin detection method - when not aligning logos or markings towards the cameras - is not so accurate.
Question is then, how "not so accurate" is it then? 10% off maybe, or maybe 50% or even more.
If that's the case, then we ask what's the point of it all. You may as well just wing it. Which we are sure many do with great sales results.
Bcam price: $ 3,499.00
Bcam installation and setup for CX6/F6 systems
The CX6 system uses 6 cameras to capture ball spin as well as club and ball tracking.
Note that there are 2 banks of 4 cameras in the CX6 Control Panel
Cameras 5 and 6 on Bank 2 are the two ball spin cameras
Cameras 3 and 4 on Bank 1 are the two club tracking cameras
while cameras 1 and 2 are the ball tracking cameras
New flash activation sensor in the trigger mat for CTS & Bcam systems
The new CTS/Bcam flash activation sensor prevents the CTS & Bcam from triggering flashes during a club waggle or when teeing up
The flash activation sensor detects a club back swing and only then allows the flash unit to fire within a 3 second time window
Other than preventing possible annoying flashes, the flash sensor extends the life of the flash unit 10 fold
The CX6 trigger mat features multiple trigger sensors
There are 4 labeled 25ft long stereo cables on the trigger mat that are connected to the CTS and Bcam cameras
The flash activation sensors that detect a back swing are optional but recommended
Aiming the Bcam cameras
The Bcam cameras should be aimed at the ball when on the tee position on the trigger mat.
Set the shutter speed to around 10,000 (right click on the shutter speed to jump 10,000) and switch "Video Stream Mode" ON.
You will then be able to see the ball in real time video.
Adjust the lens focus dial so that the ball is in focus.
Then switch back the shutter speed to around 80. (or right click to jump back to 80).
Ball spin camera Lens focus when using IR light
Due to the different wave lengths of IR and visible light, lens focus is also different.
i.e. when a camera lens is focused on an object using visible light and you then take a picture using IR light, the object will appear out of focus.
The above images show just how out of focus the golf ball is when using IR light compared to the focus of the ball using visible light.
To correct this - as in the third image - the focus dial on the lens has to be turned very slightly anti-clockwise to the left after it has been focused in visible light..
Check the focus by grabbing new images using either the "soft trigger" with the IR flash ON or by waving an object over the trigger mat sensor.
Improved ball spin detection when using the ball logo as markings.
We've improved the ball logo detection in this version of the CP to work with out of focus ball images.
June 18 2018
Bcam and LX systems.
Measuring ball spin using the ball's logo.
New logo matching end detection.
An issue with measuring ball spin using the ball's logo is that the correct matching ends of the logo must be detected in order to correctly measure the amount of rotation within the time frame..
i.e. if one end of the logo is found in image 1 then that same end has to found in image 2. Failing to do this can result in very different ball spin rate measurements.
The above two images show a ball spinning at a rate of 8321 rpm. We know this because the amount of rotation within the 1 ms frame delay was 149.78 degrees.
And we only know the correct amount of rotation because the Letter "C" in the Calloway logo has been detected correctly in both frames. This is shown by the two red cross hairs over the letter "C".
Without this new "Matching logo end detection" feature, the CP image processing may well get the ends mixed up and then a totally different amount of rotation will be measured
(i.e. 30.22 degrees here) and thus a totally different and false ball spin rate will be calculated. (Note that the two sets of images are from the same shot.)
As can be seen from the above two images, the letter "C" in the Calloway logo has not been detected in image 2 (i.e. there's a green cross hair on the "C" instead of a red cross hair).
And thus a false spin rate measurement was calculated (i.e. 1678 rpm instead of the real 8321 rpm).
It should be noted that not all ball logos have a dominant end and thus it may be required to use a black magic marker or black ink pen to accent one end of the logo.
Note that measuring ball spin using the logo (or any marked balls like those with About Golf systems) is the only way a camera method of ball spin detection is able to do this in real time. i.e. without a long 2 to 4 second or so lag time (SkyTrak / GC2 etc).
While radar systems (Trackman, FlightScope etc) require metallic dots be applied to the ball and the ball be placed with the dot facing upwards.