International Water Ski Federation Video Jump Manual

IWSF Video Jump Manual

This is the basic instruction manual for video jump distance measurement and the operation of the video jump distance measurement program.

Both the original DOS version and the new Windows version will be detailed in this manual.

These programs are available from Bob Corson. Please contact me via email at

Video Jump System Basic Instructions

The intent of this document is to give basic information and instructions about
the video jump system.

Theory of Operation
The video jump system uses computer and video technology to be able to measure
jump distances.  Buoys are placed in the water in front of the jump roughly in
squares.  The skier lands inside these squares.  The buoys are surveyed so that
their exact positions are known.  These positions are fed into the computer.  A
video camera is set up perpendicular to the center of each box of buoys.  This
video picture is put on the computer screen with a graphics overlay.  The
overlay is used to calibrate the buoys to their screen positions.  Mathematical
transposition is used to create a mathematical representation of any screen
position inside the square to its actual physical location and then calculate
the distance between that point and the jump.  As the jumper lands, the video is
frozen.  The cursor is then used to indicate the closest point of contact in the
water to the jump ramp.  This is the point of measurement.  A factor of 2.1
meters is added to this measurement to give the equivalent distance measured by
the Johnson Jump Meter system.  This is added automatically by the computer.

Equipment Required
a) video cameras
	one camera per box of buoys.  The camera can be home video quality
b) cabling
	standard COAX cable RG59 is used.  This is the same as is used for cable
TV.  The cable has to go to the computer system from the camera.  This probably
shouldn't exceed 1000 ft without amplification.
c) VCR
	One VCR per video camera is required
d) Computer
	Standard IBM PC or clone.  A 386 will probably work.  A 486 is better.
The optimal setup uses two computers so that you don't have to switch between
views during a jump.
e) Overlay Card
	The overlay card that the program is written for is the Creative Labs
Video Blaster.  The most recent version is the VBSE100.  The DOS program will work
with a generic overlay card, but will not implement any of the special Video
Blaster features.  The Windows program requires the SE100.
The Video Blaster has three video inputs.
f). NTSC output generator (optional)
	This box takes the screen VGA image and outputs a NTSC TV signal that can
be fed to a monitor and/or to a VCR for recording.

Site Set Up
Buoys are set in line with the center-line of the jump and a line 10m out from
the center of the jump.  In the distance direction they are set in 10-20 meter
increments.  A typical setup might be buoys at 20m, 35m, 50m, and 65m on both
the centerline and the 10m line giving 4 boxes of buoys.  These boxes are also
called grids.  In this case, three cameras could be used.  Another scenario
might be to put buoys at 10m increments and use two boxes for one camera so that
the longest jumps would land in a 10 m box and the shorter jumps would land in
the 20 m box (made of 2 boxes).  This is very variable depending upon the event
and the divisions in the tournament and the number of cameras available.
The buoys should be small buoys, perhaps 15 cm in diameter.
The buoy grids also must be set out so that each grid box has a unique
combination of buoy colors so that it is easily identifiable.  An example using
(R)ed and (G)reen buoys might be as follows:

                  G          G          R         R
                  G          R          G         R
                 20m        35m        50m       65m
Please note that this is an important point and will avoid much confusion,
especially if the cameras are a long distance from the computer operators.

Set the cameras roughly perpendicular to the center of the box being measured.
If you have only two cameras, you will most likely need to move them for
different events.  The cameras should be from 2 m to 10 m in height above the
surface of the water.  The further out the buoys are, the higher the camera
should be.  Higher is generally always better.
The camera should be zoomed in on the buoys so that the
near buoys almost fill the whole screen width.
Coax (RG59) cable should be used.  You will need adapters to plug into the video
equipment which uses RCA type connectors.  The camera should be connected to the
VCR line input and the VCR output should go to the overlay card in the computer.
These cables might typically be 100 meters.
It is best to use 2 486 type computers, one for each camera grid.  In this way,
you won't have to switch the view as the jumper is landing.  For the windows program,
a 486-33DX is the minimum if you want to save GIF files.

Program Operation - Windows program
The current Windows program, vidjmpj.exe was developed under Visual Basic.
The program is new and still being enhanced as constructive criticism is received.
A copy of the program is available at the following site -
The program is in 3 subdirectories of the incoming directory.  The three sub-directories
should be loaded on to three floppy disks which then act as an installation set.
There are also configuration files on disk three which need to be transferred to the
program directory.

Be sure that the SE100 software is loaded and especially the MCI Drivers.
The program runs in windows 3.1 or win95

Start the program from the windows run function.
The program will ask if there is a vconfig.txt file in the application directory.
There should be so say yes.  If there isn't and that fails, say no and create
one later with the Config menu in the startup screen.  The vconfig.txt file gives
administration information to the program on file directories for results, gifs,
and initialization parameters.  The standard setup should be that there is a
directory with the tournament name (96masters) with three sub-directories as follows:

If you had a vconfig.txt file, the paths will be displayed in message boxes before the
start screen is displayed.

This screen comes up as a full screen window with live video in the window.
The menu options are as follows:

go to buoy and survey setup screen

go to measurement screen - disallowed until a proper setup is entered

displays the current results text file

Sub-menu items to do the following:
Change the results file path\filename
Change the GIF path
Change the Initialization file path
Change the tournament name
	The above changes are all stored in vconfig.txt in the jump program directory
Change left-to-right  -  set for direction of jumping
Barefoot - if set to barefoot, do not add the 2.1m offset  Note: if it says Barefoot in the
menu, it means to change to Barefoot.  If it is in barefoot mode it will say Tournament
in this menu item.
Message color - change the messages n the measurement screen to this color to allow for
different background colors in the video.

This screen displays live video and input boxes for the survey data.  The menu items are as follows:
Load - Loads a previously saved initialization file

Save - Saves an initialization file


There is an Alert Icon on the left side of the screen.  If the input is incomplete, it is an
exclaimation point.  If the input is completed, it is a happy face.  The program will warn
you if you try to leave the screen without a happy face.  If you leave without a happy
face, you cannot enter the measurement screen.

This video should be as you will operate the measurement system.  The idea here is to
calibrate the jump course buoys to the survey.  You will need an XY survey of the
jump course buoys and the jump.  Enter this data in the boxes indicated.
Click on a radio button to position the grid markersd on the buoys.  The radio
buttons are in the same position as the buoy, upper left, upper right, etc.
Click the button and then click the mouse point on the exact center of the
buoy at the waterline (center of the buoy means the center of the inside of the
buoy at the water level - some judgement required).  
Do this for all four buoys of the grid box.  When you are satisified, click on the
COMPLETE button to do the transform calculations.  You will be rewarded with a
happy face.  Now use the save menu to save the initialization file.  A customary
file name for example would be tl2540.ipt for the Twin Lakes tournament grid
from 25m to 40m.  Now if you enter the startup screen and use the Load
menu right away to load this file, you will have a happy face.
Be sure to give the file a good desciption as this description will be displayed
on the measurement screen to remind you what box you are in.

The Draw buoys button is used when you load a file to draw the crosses at the
buoy locations to be sure that the setup hasn't changed or the camera moved.
If you move the camera and move it back, you only have to load the correct grid
box file, re-position the four buoy markers, re-compute with the COMPLETE button
and save the file to re-set up.

Exit back to the Start Screen


The measurement screen does the work of the program and is the most complex screen.
The following menu items are on the screen:
Freeze - press ALT F to freze the screen.  I found that the keyboard operation was the most
reliable.  You can just watch the skier on the water and hold down ALT and press F when he
hits the water.

Save Picture - This allows you to save the frozen picture on the screen.  This
shouldn't be necessary to use since it is normally saved as part of the "Record Jump"

Load Picture - This function allows you to load a previously saved gif to check it again.  
Be sure that the appropriate grid is being used by pressing the show grid button to match up the
crosses on the buoys.  The file names are numerical, but quite easy once you understand
the way they are created.  The number is the time of the jump in the following format:
MDDHHmms.gif where 
M is the second digit of the month   (July = 7, October = 0)
DD is the day of the month (October 15 = 15)
HH is the hour time in 24 hour format
mm is the number of minutes of the current time
s is the tens of seconds

Example  - a jump that occured on July 10 at 14:30:45 would have the file name 71014304.gif.
Each result is also timestamped in the results file so they may be matched quite accurately
and exactly.  The GIF is saved a few seconds after the result is posted in the file.

Results - This displays the result file on the screen


The screen also includes the following text input boxes:
Skier Name
-- Enter the skier's name in this box.  Any change to this box resets the jump number to 1
Jump number - may be edited manually, but increments automatically

Distance in meters - output of calculated distance in meters
Distance in feet

Unfreeze - Unfreezes the video screen.  When frozen a large "FROZEN" sign is 
on the screen.

Record Jump - calculates and shows the distance and saves the result in the result file. An option
box will come up to give you the option of saving or not saving the GIF.  Always save scored

Verify - allows verification of a previous jump by letting you bring up the GIF file
and positioning the mouse pointer to the same XY point as indicated in the results file
to show that the jump was measured correctly.  When this button is on text boxes appear
that show the X and Y coordinates of the mouse pointer.  

Show Grid - This button is very important and should always be pressed to show the grid.
judges should constantly monitor that the crosses are on the buoys to ensure that the
camera has not moved or come out of alignment.

Fall - only one of these two can be turned on.  Hit the appropriate button and "Record Jump"
if the skier passes or falls.

Man. Reride - hit this if there is a fast speed reride- it will clear when you unfreeze the screen.
If you hit it when the screen is not frozen, it will clear immediately.  The only function is to
put an appropriate comment in the results file and clear the distance results boxes.

Opt. reride - This operates similarly to the mandatory reride button except it doesn't clear the
distance boxes.

Comment - Pressing this allows you to enter a comment in the results file.

Other grid - use this in a two computer operation when the jump is on theother computer.
Enter the distance from the other computer IN METERS.


Program Operation - DOS program
The current DOS program vidjp95h was developed under QuickBasic Version 4.5.  The
program VIDJP95H.BAS requires the Quick Basic environment.  The text file of the
program VIDJP95H.TXT will run under Q BASIC which is supplied with DOS 5.0 and
above.  Just type QBASIC at the C:\ prompt and Q BASIC should come up.  Use the
ESCape key to clear the screen.  ALT F will pull down the File Menu.  Choose O
for Open and select the VIDJP95H.TXT program.  Then run the program by typing
ALT R (Enter)or F5.  The screen will return to a DOS screen and ask you for a
file name in which to store the results.  Select a name and input it.  Do not
include a suffix.  The .TXT suffix will be added to this file name.  The next
prompt asks for the type of Video Blaster card.  Enter as requested.  Then the
main menu will come up looking like this:

Video Jump Distance Measurement
Main Menu
1 - Setup and Calibration
2 - Measure Jump Distance
3 - Instructions
4 - Type Results So Far
5 - Exit

	Setup and Configuration
Enter 1 for Setup and Configuration to get the Setup Menu as follows:

New Jump Distance Measurement
Initialization Calibration Menu

Direction is Left to Right

1 - Input Screen Initialization Points
2 - Input Survey Coordinates
3 - Select Grid Scale
4 - Display Initialization Points
5 - Display Grid
6 - Save Initialization Points in file
7 - Display directory of initialization point files
8 - Display contents of initialization point files
9 - Load Initialization Point file
10 - Change measurement mode  (in first point mode now)
11 - Configuration Parameters
12 - Video Test
13 - EXIT

Function Description:
1 - Input Screen Initialization Points
	Set the screen points to match the screen location to match the position
of the buoys.  Follow the directions to match the buoys against screen positions
by moving the horizontal and vertical cursors.  Pay careful attention to the
numbering of the buoys.

2 - Input Survey Coordinates
The measurement buoys should be surveyed as well as the position of the jump.
These positions are fed into the computer here.

3 - Select Grid Scale
The grid usually starts with the shortest measurement buoy distance and goes in
2m increments until it gets to the next buoy.

4 - Display Initialization Points
This screen shows the initialization points overlaid on the video to check

5 - Display Grid
This function displays the grid with the parameters input.

6 - Save Initialization Points in file
After functions 1,2, &3 are complete, save the numbers in a file of your

7 - Display directory of initialization point files
This function shows what initialization files are already on the system.
Remember to include the full path.

8 - Display contents of initialization point files
This function shows the indicated configuration file (suffix .ipt) contents.
these files are text files.

9 - Load Initialization Point file
Indicate a file to be loaded.

10 - Change measurement mode  (in first point mode now)
Originally, the program was set up to measure either first point or center of
splash.  The first point is the method that you should use as the other produces
mixed results.

11 - Configuration Parameters
There are certain parameters that you can change in this menu.  The most
important have to do with the grid.  The program can be configured to show the
distance grid as well as the instantaneous distance as you move the cursor.
These are turned off so the judge will pick the distance "blind" rather than
knowing what the distance is so he won't be predisposed to "help" the skier or
be influenced by the distance when he is picking the first point on the screen..
Video parameters can also be changed.  An XYFILE name can be chosen.  The
program records an XY position for each measurement for later analysis.

12 - Video Test
This menu option turns on the Video Blaster to test video.

13 - EXIT

Calibration Operation
Each grid must be calibrated for each camera view.  The grids are numbered 1,2,
&3.  The grid is requested during the calibration operations (menu items 1,2,
and 3) as well as when the resulting calibration file is stored.  If two
computers are used, each computer should have all of the grids in it for backup

The measurement screen will first ask for a skier name and a jump number before
measurement can start.  the video is shown on the screen overlaid by 4 crosses
showing the position of the four calibration buoys.  (note: It is important to
pay constant attention to these buoy calibration marks.  If they shift from the
calibration position, the screen must be re calibrated.  This would indicate
that the camera moved and that perhaps needs a more secure mounting)  Also, a
small cross showing the point for first point of impact and a vertical line 2.1
m in front of it that shows the approximate center of the splash of the jump.
The mechanical process of measuring the jump is accomplished by typing in single
letter commands while in the measurement screen.  The basic command sequence
would be for the operator to observe the skier landing in the buoy box.  As the
skier lands the operator will press "f" to freeze the screen.  This must be done
quickly as the skier lands and will take some practice to get it right.  The
distinctive small splash that marks the first point of contact persists for
about 0.7 seconds.  There is also a slight delay between the pressing of the
freeze command and its effect.  Once the picture is frozen, the "cross" cursor
must be moved to the first point of impact.  There are several key commands that
move the cursor.  The typical ones to use would be CTRL (arrow) for a gross
movement to the vicinity of the splash and then just the (arrow) key for the
fine adjustment.  The center of the cross must be at the impact point on the
surface of the water both horizontally and vertically.  Once this is positioned,
press "Enter" to display the distance on the screen in feet and meters and store
it in the results file as well as increment the jump number.  A "z" command will
erase the distance display to be ready for the next jump.
If the jump is missed, then the operator must stop the VCR, back it up to the
point where the skiers is seen and freeze the video at that point.  Depending
upon the controls of the VCR, this may be easy or cumbersome.  The VCR should be
selected for its capabilities in this area.  If the controls are sophisticated,
the picture can be stopped with the VCR 1 frame after the skier's skis touch the
water for the most accurate and easy measurement.  Be careful if using the
freeze frame on the VCR that the buoy indicator crosses still are aligned
correctly as some VCR's shift the picture slightly when in freeze frame mode.
If only one computer is used, the operator must switch between grids to get the
landing on the screen so that it can be frozen.  This is more difficult and
results in more VCR operation.  However, if the tournament is not a major
competition, this additional 30 second or so delay is probably acceptable.
However, at a major tournament, it will be very frantic while the operator tries
to get the distance and everyone wants to know the distance.  Typically, the
distance can be obtained within 5 to 10 seconds.
When using two computers (the desired method), one computer is on the longer
grid and one is on the shorter.  The two operators should sit side by side.
When the jump landing is frozen, both operators should decide on the cross
cursor placement before recording the distance.  In an international tournament,
these two operators should be from different countries.  Also, the during
competition, the instantaneous measurement feature must be turned off as well as
the grid lines so that the operators are selecting the distance "blind".  Also,
the two computers must be kept in sync.  This means that on the computer that
the skier didn't land in, the distance must be entered in as the distance on the
other computer.  (See instructions in next section).  Two other useful commands
are the "h" command which will display all of the key commands on the screen and
the "p" command which will display the results so far.

This menu item displays all of the key commands that are used during the
measurement mode.  The list plus a brief description of each command follows.
Note that the command key is in brackets so that (r)ight means to press the "r"
key to implement the function.

a) Cursor Controls
	right, left, up, down arrows   - 1 pixel movement
	ctrl arrow    - 20 pixels"
	(r)ight, (l)eft, (u)p, d(own) keys - 20 pixel"
	(R)ight, (L)eft, (U)p, D(own) keys - 20 pixels"

b) (f)reeze the video
Pressing the "f" key freezes the video picture on the screen.  Note that if you
hold down the f key or leave finger pressure on it, you may get multiple freezes
and miss the one you wanted.  Experiment with your particular computer keyboard
to get the feel of it.

c) (t)haw the video
Pressing "t" unfreezes the video.  It has no other effect

Splash Mode measurement commands - disregard these commands
     (c)ircle on               (e)rase circle
     (C)ircle to be larger (.25 step)
     (E)rase circle size (step smaller)
     note: circle only shown in splash measurement mode"

d) (g)o to start of measurement screen
This is used to refresh the grid if the grid is being displayed.  Moving the
cursor across the grid erases it until it is refreshed or a jump is measured
which automatically refreshes it.

e) Enter (show distance in feet, meters in large letters)
This is the basic operational command.  This not only displays the distance, but
officially records the jump in the results file.

f) (z) erase distance display

g) Grid Selection Commands
(1) to use camera #1 (source 0)
(2) to use camera #2 (source 1)
(3) to use camera #3 (source 2)

Use these commands to select the desired measurement grid.

h) (n) new skier name
When a skier is finished his jumps, the next skier is entered with this command.

i) jump on other (s)creen
When in two computer mode and the jump is recorded on the other screen, use this
command to enter the distance and increment the jump number to keep the two
computers synchronized.
Note if the skier lands so that the measurement point is available on both
screens, the official screen is the one where the measured point is inside the
buoy grid.  If measured on both screens, the distance should be the same, but
may differ by 0.1 m if the jump is just on the boundary of the measurement.  A
measurement will still be accurate if it is 1-2 m outside the box in a
horizontal direction, but this should be avoided.

j) n(o)te to add after jump
This is to make a notation for later reference.  It will ask you for a comment
that will be time stamped and added into the performance results.

k) (m)iss add PASS/BALK/FALL
Use this function to note when the skier misses a jump.  This function
increments the jump number.

l) (p)erformances up to now
This function prints the performances on the screen up to now.  It always prints
all of the performances, a screen at a time.  Pressing the space bar advances
the screen.  Note that there is no provision in the program to print the results
file.  This is intended to be done outside the program with DOS commands or with
the EDIT program supplied with DOS.

m)    rer(i)de
When there is a reride, this function lets you note if it was optional or
mandatory.  This would be mostly for bad speed or path rerides.

n)(q)uit measurement
Go back to Main Menu

o) (h)elp
Display the above commands on the screen.

This menu function displays the results so far.  The results are in a file that
the operator named upon start of the program.

Homologation and records
To certify the jump measurement setup, the homologator must survey the jump
position and the position of the marker buoys.  The accuracy of the setup may be
checked by moving the measurement cross cursor to each buoy and measuring the
distance to each buoy which can also be calculated using the survey
measurements.  Don't forget to subtract off the 2.1m added on by the program!
For a record submission, the complete survey must be submitted along with a copy
of the video showing the jump landing.  This will be sufficient to verify the
distance.  Also note the color scheme of the buoys.