CX Converging Stereo Camera Setup
CX Stereo ball tracking
The two cameras ( V and H cams) are mounted around 4 to 6 ft ahead of the player's normal ball striking position and aproximately 8ft apart - centered.
Note that the cameras are mounted sideways in order to increase the left and right FOV.
Aiming the cameras to the center line
Place a ball or any clearly visible white object on the floor between the two cameras.
Starting with camera 1, select video stream mode and aim the camera so that the white ball appears exactly in the center of the image.
There are vertical and horizontal center lines visible in the image to help with this.
Do the same for camera 2.
Mounting the cameras sideways means the direction of play is then in the vertical direction
i.e. from down to up in the camera images instead of from right to left.
You will thus have to move the "Ball Launch position" to the bottom center of the camera image.
The above shows the converging camera calibration table that is automatically loaded when "Converging cameras" option is selected
The table consists of 5 values that are an automatically calculated:
Note that if both cameras are perfectly aimed at the same center line then disparity at the converging point at floor level will be zero.
This will probably prove to be difficult to achieve but at least the disparity number at floor level should be a low number.
The above table shows a disparity (Disp) of 24 at floor level.
A graph plot of disparity to golf ball height shows a non-linear exponential curve.
Note: please use Control Panel version 18.104.22.168 or greater for this procedure.
Should re-calibration be required then the following calibration procedure should be made:
In order to calibrate, we need to raise a 20cm white strip mounted on a black card from the floor up to around 170cm in 10cm steps on the center line.
You can use any method you like to raise the strip off the ground in the 10cm steps.
Attaching the strip to a metric tape measure that is suspended from the center line of the enclosure and extended to the floor is one method.
The above image shows a white strip card directly attached to a tape measure that can simply be moved up or down to the desired height.
You could also use an extend-able camera tripod.
Note that the calibration table consists of 17 row entries at set 10cm distances from 0 cm to 170 cm.
i.e. 0, 10, 20 ... to 170 cm
17 Calibration steps
The above image shows the white strip connected to the tape measure with the slider.
Using the calibration slider on the tape measure, a complete calibration can be done in 10 to 15 minutes.
When testing, set both RAW Path and RAW Launch angle to ON
Note that the above image is from the parallel setup page where the strip orientation is from right to left.
The converging camera strip oprientation is vertical i.e from down to up.
You can view the complete calibration table by selecting the "Show calibration table" option.
Virtual checker board
Instead of using a large cumbersome checker board to calibrate the stereo cameras,
this method uses a virtual checker board that automatically scales and positions itself depending on the position and image size of the white tube
Note that the CX Surround uses super low distortion lenses so lens bend doesn't have to be taken into account
Although the real distance (d) the ball travels (and thus the ball speed) within the camera exposure time is always measured using RAW LA and Path
(i.e. as measured from the both ends of the ball trace)
it will be more accurate to measure LA and path using fixed launch positions for chipping as by the time the ball is in the FOV of the cameras with slow shots
the ball may well be descending and thus launch angles will be less or even negative if measured from trace ends instead of a known launch position height.
Note that when using a fixed launch position (i.e. when both the RAW LA and RAW path options are switched off)
then the fixed "Ball launch position" has to be set in both the left and right cameras separately
as the left and right cameras will see the launch position in a different places.
Switch RAW Path and RAW LA on/off in camera 2 of the Control Panel
Pros and Cons of Stereoscopic vs H cam V cam setups
The above screen shots are from customer Kevin showing the left and right camera images os a full shot using the new Converging stereo setup.
Kevin and Keith's comments
I decided to start with little brook manor as you suggested. I know it well since it is one of the R-Motion courses. -I get consistently good traces on full swings as well as putting.
-Putting seemed pretty good! I am no expert and I am out of practice but I felt pretty confident with the distances. -Short chips are a problem with spin. I
like to play bump and runs and the ball would carry the proper distance but instead of running they would backspin. I turned down chipping within 17yards down to 3000 from 5000.
I may turn it down more. -Most full swing shots I would say were great! Fat shots were short and pure shots went what I would say is my norm. I had a few baffling shots. I hit my 5 iron in the 170-180 range
. I had a few fly over 200yards (uphill!). I also hit my 4hybrid about 215. Most were in that range when struck well. I had one that went 265 which is in no way possible for me
I checked the cameras and both traces picked up properly. (I should have taken screen shots) -I believe I corrected my wedge issue with the clubhead getting into the FOV.
I am positioning the ball just in front of the rear line sensor which moved me back just enough. I am a little concerned how this may effect club face and direction if it may move the ball left or right.
I figured out a way to get a proper LA with my set up. I shifted the image up so that I can move my launch position back.
I also added a 12x12 fiberbuilt fairway piece ahead of my hitting area. I chip from there and find that the ball flight and carry is pretty accurate on slow chips.
Because I moved the launch position back, full shots are within Ĺ degree of the raw angle shots. So, good news!!!!! You donít have to add anything to the control panel.
Chips that carry 4 yards in the basement, carry 4 yards in the game ( after reducing my LW and SW to 90%)
Flop shots have to be taken from further back as the club head sometimes comes into play. I think that I have everything working as well as my X,Y system.
Short chips are working well now.
The above video is from customer Keith showing putting using the new Converging stereo setup.
Martin, Yesterday I was having trouble with IBS when it switched to putting. The screen filled with white specs. Today I tried it with the putting camera gain turned all the way down to zero. Problem solved. I suppose that this is the case due to the difference in shutter speed. I did a computer reboot and found that I didn’t have any no reads during the 13 holes that I played today. Maybe suggest that a reboot might be helpful after a CP update. IBS was turned on and it works great. I will be switching out to a full putting green shortly and I am hoping that I won’t have any issues. I have tested the LS cam with pieces of my stance mat from FB. I can adjusted it the it works fine. Chipping and putting was working great. Off the tee, I thought that the ball flight was too straight…. Maybe too forgiving. So I set up for a big draw. I managed to get 27 degrees of right SA……so my system can pick up mishits for sure. Then I set up for a fade but with less SS. The ball started right about 2 degrees and had left SA of 9.7 degrees. So the ball started right and faded back to the left nicely. I am really happy with the new stereo set up. It seems like Kevin is dialing in his settings as well. And the best part…. There is nothing for you to fix at this time.
Hey Martin and Keith, I just wanted to say thanks and I am in love!!! I believe I have made almost all of my adjustments and the PX5 is awesome! Keith kept telling me to use IBS and I finally switched over tonight.... WOW! The images and reads are great. Attached is two 6 iron pics to show my IBS images. I played a full round tonight. No reads were at a minimum. I had one putt, one tee shot (which I launched from CP), but then I did have to close TGC and GSA and reopen when I was trying to take a half wedge shot that wasn't reading after multiple attempts. After the restart I believe I had one more no read. Keith- I started Q school tonight. My TGC username is Swiggs. It looks like you check on some of the scoring so I wanted to let you know I had one rewind near the very beginning. I hit my hybrid (on 5 wood setting) and it travelled 45 yards too far. I went into the CP and noticed spin was at 7000 and speed was 117%. I brought down to 100% and 3000ish spin and used the CP to relaunch after. ( I don't want to be the new guy who cheats and still gets last place! ha!)