CX Camera Vcam & Hcam
The CX V and H cam cameras are used to measure
ball launch angle and speed (Vcam) and ball direction or path (Hcam)
The above image from the GSA Golf Control Panel is a true live shot from the floor mounted vertical launch angle (Vcam) camera of a ball hit with a 7 iron.
The camera field of view is actually far greater than what is actually required
and captures the player (on the right), the projection screen (on the left) and the floor.
The blue border lines dictate the valid field of view
and the red line dictates the maximum ball height a ball will have to be considered as a rolling ball or sculled shot.
Note that the length of the ball trace is directly proportional to the ball's speed
and providing the camera's exposure time (10 milli seconds here) and the pixel to cm scale (0.2 here) is constant - which it always is - this correlation is constant and consistent.
i.e. no matter what the launch angle is, the length of the ball trace will always be the same for a given ball speed and will always be directly proportional to the ball's speed .
Note the strong contrast between the background and the ball trace.
This is achieved by setting the camera gain high which amplifies the contrast.
The room is actually much lighter so you are not playing in the dark but the camera sees it as very dark due to the fast shutter speed.
The ball is illuminated by the overhead and side mounted halogen and IR LED lamps.
View camera images of your shots in the GSA Golf Control Panel camera windows
The side mounted Vcam detects vertical launch angle and speed of the ball
The ceiling mounted Hcam camera detects ball path for normal shots
and ball path plus speed when putting
CX2/CX3 ball tracking wirth a single IR LED lamp
A number of CX customers have expressed their doubts recently that a single IR LED lamp is sufficient for the ball tracking
The above 2 images - that are direct from a customer remote support recently - show that the ball traces using just the supplied single IR LED lamp are perfect.
Using two IR lamps to illuminate the ball from both the side and top
The above is a screen shot from customer "Jim" showing a perfect ball trace achieved by placing one IR LED lamp next to the Vcam as well as the ceiling mounted IR LED lamp
Mounting the Vcam camera
The Vcam (Vertical launch camera) is floor mounted (either left or right hand side of the enclosure or room).
The camera views the ball from the side and measures ball launch angle and ball speed.
It is mounted in line with the overhead mounted Hcam and Line scan cameras (as shown in the above image).
The Vcam camera should be facing the opposite wall and tilted up some 25 to 30 degrees.
If the Vcam is not tilted upwards then too much floor will be in the FOV of the camera (as shown in the above left image).
When adjusting the camera's aim, switch to "Video Stream" mode in the CP's camera window.
Mounting the Hcam camera
The Hcam (Horizontal plane camera) is overhead mounted. It should be mounted such that the ball's direction of play is right to left as viewed by the camera.
On the back of the camera you should see the text "Screen" to help assist with the mounting direction. Mount such that this text is towards the projector impact screen.
The above 2 images show what the ball traces should look like using just the supplied single IR LED lamp.
Equally, the background in the FOV of the Vcam must also be dark and non-reflective
The above Vcam image is from a customer that obviously missed the instruction that the background in the FOV of the camera should be non-reflective.
This is what the background and a ball trace from the Vcam camera should look like.
Customer "Ken" sent us this Vcam image after a shot.
Notice that the bright ball trace is not being picked because the background is too light.
After eiether reducing the Vcam camera gain or increasing the "Min ball gray scale" to 200, the problem is solved.
What to look out for with the Hcam when using more reflective turf grass surfaces
(i.e. not using the supplied black carpet)
When using regular grass turf flooring, the contrast between the ball trace and the underlying grass turf carpeting will not be so great.
It is thus essential to set the "Min Gray Scales" correctly for both putting and regular shots
The above image shows what a normally detected putt or shot on higher reflective grass turf flooring would look like
In this above image the putt is not correctly detected
Adjusting the camera's view and setting the valid FOV borders.
The system searches for golf ball traces only in a certain segment of the captured images and does not use the entire FOV of the camera.
This segment is determined by the blue border lines. In the case of the vertical launch camera this is Min / Max height and Start and End borders.
These define the Valid FOV and are preset but you may need to adjust slightly according to your enclosure.
To test, place two golf balls at either far end of the sensor array trigger but so that they do not actually cover any sensors.
Aim the camera so that both balls are as low as possible in the FOV. Place the balls at different distances if the ball nearest the camera is obscuring the further end ball.
the direction of play in the camera image is always from right to left.
If you have mounted the cameras so that this is reversed, then select the X Reversed setting.
If the ball direction in the camera image is going up to down or vice-versa then you will have to turn the camera 90 degrees.
Select the Min Height button and use the keyboard arrow keys to adjust the Min Height blue border line so that the visible floor is below it.
Select the Max Height for Ball Rolling button and use the keyboard arrow keys to adjust the red border line so that the ball at the far end of the trigger is just below it.
The Start blue border should be set exactly in line with the line of trigger sensors.
To ensure this place a golf ball next to and in line with the sensors and grab an image by clicking the Soft Trigger button in the Camera window.
Move the Start Border line so that the line is down the center of the ball in the image.
Double check by taking a shot so that you can see that the start of the ball trace is in the valid FOV.
The above image (sent in from a customer that reported that the measured ball speeds were too slow and carry distances were too short)
shows that the ball trace is starting way behind the start border line. The start border must be moved to just behind the beginning of the trace so that the full trace length is in the valid FOV.
The Left End and Max Height border lines should be set to cut out any bright objects in the FOV.
Using the Image shift controls to fine adjust the Vcam's FOV
After adjusting the angle of the Vcam you may still find that the flooring is still in the FOV of the camera.
Using the Y shift control allows you to bring the view of the camera down.
Ball Speed : Setting the scale factor for correct ball speed detection
Ball speed is directly proportional to the length of the ball trace captured by the camera during the exposure time.
In order to calculate ball speed we need factors two factors: Time and Distance. This is then used in the equation : Speed = Distance/Time
Time is simply the camera's shutter speed i.e. exposure time.
Distance is the length of the ball trace.
As the camera sees only pixels a real distance-to-pixel scale factor must be used to calculate the real distance traveled.
The system uses the scale value to calculate the real distance (in centi-meters or inches) the ball has traveled during the exposure time.
Thus, adjusting the scale factor will increase or decrease the measured ball speed and thus the carry distance of a shot.
To set the scale setting place a yard stick or any object of a known length on the floor in front of the vertical camera at the same distance as the tee on the hitting mat.
In the Vertical launch camera window of the GSA Control Panel click the Soft Trigger button to capture an image so that the yard stick is visible.
Move the Start Border line to one end of the object and the Left End line to the other end.
Adjust the Scale factor so that the calculated length (shown at the bottom of the image window) is equal to the known length of the yard stick or object in the captured image.
Testing the vertical launch camera.
Select Video Trigger Mode and hit a ball.
You should then see the trace of a brightly lit ball in the image with two green crosses at either end.
The read out at top right of the screen should show the measured launch angle and ball speed.
If the ball trace is not completely within the blue border lines, then adjust these accordingly.
If you do not see anything, then check that the trigger function of the camera by passing an object (a club or your foot) over the trigger sensors.
You should see that the camera will take a shot every time.
Depending on your specific lighting conditions, you should adjust shutter speed, camera gain and gray scale to obtain ball trace images similar to those shown below.
Captured image of full 3 wood shot
Captured image of wedge shot
Raw Angle / Launch Angle
If you like you can now switch to Raw launch angles. The raw angle is the angle between the start and the end of the trace instead of between the defined ball launch position and the beginning of the trace.
Use the new "Use RAW launch angle" button to switch this on or off.
Note that when using raw angles the angle measured between small traces won't be so accurate and when chipping, the ball may already be on the downward path in which case the ball launch reading will be negative.
Ball Launch Position
When setting the ball launch position you might find that this position is not in the field of view of the camera. i.e. it's further right.
In this case continue moving the launch position further right until you see the launch position wrap around in the camera window - as above.
The distance that launch position is from the trigger is displayed in inches and centimeters.
Physically measure the distance the launch (tee) position is on the sensor mat to the trigger array and set the launch position in the camera window to correspond to this.
Another way of doing this is to make a shot so that you can see the trace in the camera window.
Then move the launch position so that the launch angle is the same as the RAW angle - as shown in the above image.
Sand and Rough launch Positions
If you have sand and rough panels you should set these positions in the Vcam camera
so that the system can calculate the vertical launch angle from these positions when hitting from sand or rough.
As of version 184.108.40.206 of the Control Panel these positions can be automatically set to their defaults by right clicking anywhere on the screen when in Sand or Rough positioning mode.
The positions are shown in fainter shades or yellow (sand position) and green (rough) position. They will normally be 12 inches and 24 inches ahead of the normal launch position on the tee.
Adjusting the measured ball speed and ball carry.
See the camera calibration page for details on how to adjust carry and ball speeds
The above video shows how to adjust both the measured club and ball speeds to effect ball carry distances.
The speed of the ball is dependant on the distance the ball traveled within the camera time frame (shutter speed).
The camera sees only pixels so a real distance-to-pixel scale factor must be used to calculate the real distance traveled.
Thus, adjusting the Scale factor will alter the measured ball speed which in turn will adjust the distance/carry the ball will have in the golf simulation software.
If you find that high shots are carrying too far in the game software, you can use the Speed Decrease setting in the Vcam window to adjust this.
A user defined percentage decrease is evenly spread over a vertical launch angle range from a user defined launch angle to 60 degrees.
The above image shows a setting that would gradually take 25 percent off the speed over a vertical launch angle range from 40 degrees to 60 degrees.
The spread is then 20 degrees ( 40 to 60) which means that the ball speed will be reduced by 1.25 percent (25 / 20) for every degree over 40 degrees.
In the above example, the ball speed - and thus the carry and roll - will be reduced by 25 percent if the launch angle is 60 degrees or greater and 1,25 percent if the launch angle is 40 degrees
When setting, use the left and right arrow keys on your PC to adjust the percentage or speed decrease and the up and down arrow keys to adjust the vertical launch angle range.
Speed controls are also displayed in every camera window when "Show Trajectory" is on.
Trajectories and carries are automatically updated with every speed adjustment
Ball speed reduction proportional to launch angle
Vcam Trace tapering
As measured ball speed is directly proportional to the length of the ball image trace , it's important that the ball trace from beginning to end is well illuminated.
With really fast high speed shots, it is possible that the ball won't be sufficiently illuminated to leave a solid trace and appears to taper out towards the end.
The image processing software in this case won't detect the full length of the trace and thus the measured ball speed will be too slow.
In order to avoid this problem additional illumination (either IR LED or Halogen) has to be added further ahead towards the screen
Left Right Ball speed and LA adjustments
When hitting balls left or right, the ball will either be getting closer or nearer to the floor mounted Vcam camera depending on it's mounted position in the enclosure. i.e. either left or right.
If the ball is getting nearer the camera then the trace will appear larger and thus the measured speed will be greater and if getting further away from the camera the trace will appear smaller and thus the measured speed will me lower than what it really is.
To compensate for this, the CP offers two solutions: 1. A fixed calibration method, 2. a user adjustable linear method.
Linear Left/Right ball speed and launch angle adjustments
In addition to L/R speed adjustments, LA adjustments may also be required when using the linear method (i.e. when calibration is switched OFF).
This is automatically done when Vcam calibration is ON but wasn't available when using the linear L/R adjustments.
L/R LA adjustments are now done using the up/down keyboard arrow keys and L/R speed adjustments are done with the left/Right arrow keys as before.
Overhead ball path camera.
The overhead camera captures the trace of a ball to measure ball path.
Setting the valid field of view of the Hcam camera.
The Hcam overhead has a larger field of view but only a small strip is actually used to capture the ball's direction. This area is called the Valid FOV.
Hit a ball to the screen to capture a new image from the Hcam.
Using the controls set the valid FOV by moving the borders. Set the Start border just past the start of the ball trace, the End border to some 6 to 8 inches behind the Start border and the Left and Right borders to approximately the edges of the line scan area.