Bowling Speeds - Radar Gun
Graham Jewitt
The following article appeared in the Cape Town newspaper the Cape Times
yesterday (15/1/96)
HI-TECH DEVICE LEAVES BOWLERS NO SECRETS
A NEW BALLISTIC measuring device leaves bowlers with few secrets. At a
Newlands match recently it revealed
that one bowler was out of condition. Dale Granger reports.
FIRST came the stump camera, and the traditionalists choked on their pink
gins. Now a unique and revolutionary
hi-tech radar used by the military to measure the speed of a bullet, is
trapping a blistering Allan Donald delivery at
145km/h.
The device, far more sophisticated than the dreaded police radar gun that
triggers off your speeding tickets, is called
the EDH Speedball and has arrived in South African cricket. It was tried out
at Newlands recently in the Test
between South Africa and India, was officially launched in Johannesburg
yesterday and will be in official action for
the first time in the third and final Test at the Wanderers from today.
Its marketing potential has already been exploited by Colgate and Mennen Speed
Stick, who are now sponsoring it
for use in sport.
The Speedball was developed by the Electronic Development House in
Stellenbosch, where one of its creators, Mr
Henry Johnson, an electrical engineer, said it had taken six years and cost
R1,6million to perfect.
He said that although the device had been adapted for cricket and other
sports, it was initially developed in 1992 for
the SADF to measure trajectories. To meet stringent criteria it had to be able
to measure a bullet (at 900m/second)
with only a 0,1% degree of inaccuracy.
Then in November last year the company started adapting the Speedball for
sport.
At Newlands, the device, a white box 700mm wide and 300mm high standing on a
white tripod, was virtually
invisible to spectators as it was placed in front of the white sidescreen. It
relayed information, instantly processed by
a computer 400 times faster than a Pentium PC, and revealed that Allan Donald
and Lance Klusener had bowled
the fastest ball of the Test each whipping down a single delivery at exactly
145 km/h.
The Speedball, using a hi-tech form of radar known as doppler radar, is far
more sophisticated than conventional
radar which transmits radio waves that bounce back off any object in its path.
The Speedball, however, ignores
stationary objects and only identifies moving objects effectively players, bat
and ball
As Johnson explained, it will not only measure the speed of the ball but also
that of the bowler on his run-up.
Perfecting the technology had been a feat in itself, as a cricket ball, made
of leather and cork, was not a natural
radar reflector but rather a "super stealth object" that lets radio waves
through.
The electromagnetic wavefront is transmitted from the Speedball as a narrow
beam that extends 80m over the
bowler's run-up area, the pitch and the area around the wicketkeeper.
Such is its sophistication that for every millimetre the ball travels from the
moment it leaves the bowler's hand its
speed is measured. It can also pinpoint precisely where the ball landed on the
pitch and its angle of deviation in the
outswinger or inswinger.
This information will initially be relayed to scoreboards and on television to
enlighten the fans on the speed and
deviation of each delivery.
"We know that when the ball leaves the bowler's hand it is at its maximum
speed," said Johnson. "And from that
moment the batsman has about 0,4 of a second to react to a real pace bowler".
However, the device can also measure how long after the ball has bounced when
it usually starts to swing it takes to
reach the batsman. On average, a player facing a "quickie" has only 0,05 of a
second to react.
The device records every ball bowled and the computer then compiles averages,
fastest and slowest balls and other
permutations.
But not all players will be delighted with the Speedball. It recently fuelled
suspicions at Newlands in the
Transvaal/WP day/night match that fiery paceman Brett Schultz was unfit.
In his opening spell Schultz was phenomenal, his deliveries pelting the
besieged Transvaal batsmen. But later they
had little problem sorting out the big blond bowler, and the Speedball
revealed that he was significantly slower at
that stage.
While Donald is consistently the fastest bowler in the SA squad, followed by
Klusener (138), the Speedball has also
revealed that Brian McMillan's average delivery is around 130km/h.
Shaun Pollock is no slouch, with an average of 125-126km/h his fastest at
Newlands was 136km/h and Hansie
Cronje consistently bowls 113km/h deliveries and reaches 119km/h.
Paul Adams sends down a delivery at 75km/h, but his faster ball, the one that
takes plenty of wickets, is
significantly swifter at 92km/h.
In contrast, Johnson said, Croatian tennis player Goran Ivanisovich could
serve an ace at 220km/h although a tennis
ball decelerated much quicker than a cricket ball.
Johnson can't wait to use the Speedball at an ice-hockey match, the fastest
non-mechanical game in the world, and
at golf tournaments.
"The Speedball is unique in the world market and the possibilities are great,"
he said, but refused to elaborate on
what the company had in mind.
This can only be left to one's imagination, although computer graphics, as
used in golf, for TV seems one option.
It should also end those famous rows in the pub about who's the nippiest.
Andrew Forsyth
Graham Jewitt wrote:
>
> The following article appeared in the Cape Town newspaper the Cape Times
> yesterday (15/1/96)
>
> HI-TECH DEVICE LEAVES BOWLERS NO SECRETS
>
> A NEW BALLISTIC measuring device leaves bowlers with few secrets. At a
> Newlands match recently it revealed
> that one bowler was out of condition. Dale Granger reports.
Pakistan test last year. That was most amusing, I think it got confused
by the length of the ball, with short ones registering as
being ridiculously slow. Still, if it doesnt work, and starts showing
that Paul Adams is the fastest thing since Tommo it will be good for a
laugh.
Andrew Forsyth
lj...@anat.uct.ac.za
Hi,
Just a question about the bowling speeds measured by the RADAR GUN.
What component of velocity does the radar gun measure ?
ie. does it measure the horizontal velocity (ie the length of the pitch
divided by the time taken to reach the batsman) see diagram(a)
or, the actual velocity ( ie the length of the ball trajectory divided
by the time taken to reach the batsman ) see diagram (b)
(b) *
* *
* *
* *
* *
bowler (a)___________________________*_________________________ batsman
(c)
As you can see from the above the diagram, the taller the bowler - the
longer the ball trajectory (b). The pitch length (a) is constant.
This means that if a short bowler and a tall bowler take the same
time for a ball bowled by them to reach the batsman - the taller bowler
is actually bowling faster than the shorter one because his ball
trajectory (b) is longer, yet his ball takes the same time to reach the
batsman as the shorter bowler's.
Both velocities should affect the batsman, as he has to play a shot by
the time the ball reaches him (ie velocity component (a) ), but his
timing which enables him to hit the ball with the middle of the bat is
also determined by the actual velocity (b) (since this determines the
height of the ball when it reaches the bat.
If a tall bowler and a short bowler both pitch the ball at point(c), and
it takes the same time for both their cricket balls to reach the batsman,
the ball from the taller bowler will hit the bat higher up than the one
from the shorter bowler.
This obviously affects the manner in which we interpret the speeds given
by the radar gun - ie. do we also need to consider the bowlers height (or
rather - the height at which he releases the ball) ?
If the radar gun only measures velocity component (a) - this means that
if tall bowler and a short bowler are both measured at say 145 kph then
the taller bowler is the more difficult one to play, since his ball is
actually moving faster.
Regards,
Lester John
Richard Lighton
In article <32DF9900...@tyco.net.au>,
Tom Atkinson <t...@tyco.net.au> wrote:
>
[snip]
> Nice diagram, Lester (or is it John?). Look at it this way: what
> measurements does the gun have to work with? If it is using radar only,
> it initially has only RANGE measurements. But, when you include TIME,
> by way of an in-built clock, you can get RATE OF CHANGE of RANGE, which
> is usually referred to as "rate of closure". So, if the gun is using
> radio ranging and time (only), then all you can possibly get is
> rate-of-closure (relative to the gun).
>
No, it is a doppler radar. It is measuring the change of frequency
between the transmitted signal and the reflected signal.
This is hardly a new idea. The same sort of system has been used
to determine the speed of baseball pitches as long as I've been
watching baseball (over 20 years) and has been used for issuing
traffic tickets for more than thirty.
But still, is the speed measured that of the ball when it reaches
the batter, or at the point of delivery? This difference is presumably
greater in cricket than in baseball, because of speed lost when
the ball bounces.
--
Richard Lighton | Drink! for you know not whence you came, nor why:
(lig...@ios.com) | Drink! for you no not why you go, nor where.
Wood-Ridge NJ | --Fitzgerald
USA | "The Rubiyatt of Omar Khayyam"
Tom Atkinson
lj...@anat.uct.ac.za wrote:
> What component of velocity does the radar gun measure ?
>
> ie. does it measure the horizontal velocity (ie the length of the pitch
> divided by the time taken to reach the batsman) see diagram(a)
>
> or, the actual velocity ( ie the length of the ball trajectory divided
> by the time taken to reach the batsman ) see diagram (b)
>
> (b) *
> * *
> * *
> * *
> * *
> bowler (a)___________________________*_________________________ batsman
> (c)
>
>
> Lester John
Nice diagram, Lester (or is it John?). Look at it this way: what
measurements does the gun have to work with? If it is using radar only,
it initially has only RANGE measurements. But, when you include TIME,
by way of an in-built clock, you can get RATE OF CHANGE of RANGE, which
is usually referred to as "rate of closure". So, if the gun is using
radio ranging and time (only), then all you can possibly get is
rate-of-closure (relative to the gun).
If one makes the assumption that the ball is travelling towards the gun,
then rate of closure can be considered equal to ball "speed" (I
deliberately avoid using the term "velocity" here).
The "logic" used by the gun is also of interest. Bear in mind that the
raw data available to the gun consists of only, 1, range measurements,
and 2, the time at which the measurements were taken. DO NOT think that
the only range measurements are from the approaching ball. There will
be numerous "returns" from the bowler, the bat, the batsman, etc. The
first thing the device must do is correlate successive returns so as to
"lock on" to a moving target. If it is very good at determining the
moving targets, it will realise there are several. From the several, it
would most probably choose the fastest moving. But, things can get very
confusing for the poor device at times. The movement of the bat, or
batsman, may obscure the ball sufficiently for the device to lose lock
on the ball. Or, worse, a return from one of these may be interpreted
as a return from the ball!
The sampling period is significant. Ideally, the sampling period would
automatically begin upon lock-on of a fast-moving target, then end very
shortly after. How does the device decide when to start and stop
sampling? If it is aided by a human, pressing a button during the
bowler's run and then pressing another button after the ball passes the
batsman, the device's job is made CONSIDERABLY easier.
The best way to measure the ball speed is to have two sets of
photo-electric cells, looking across the pitch. Of course, the sensors
would have to be extremely sensitive, to allow for fast deliveries. The
speed is then just the distance between sets, divided by the time
between sets. The presence of the sensor poles would create problems
for the players, of course, but this setup would give reliable, accurate
measurements.
Hope this helps you to understand the problems faced by
speed-measurement devices in dynamic environments.
- Tom
Kamlesh
Hi there,
I think that radar is not measuring the speed, like you said, measuring
the time period for the ball to reach to a batsman, after it was
delievered by the bowler. I think the actual path of the bowl is divided
into smaller segments and for each segment radar is measuring the speed
and give us the average speed. That is how one can say that, a certain
bowler's ball is very fast at the beginning but looses pace when it
reaches the batsman, while some other bowlers speed remains same all the
time till it reaches the batsman. Correct me if I am wrong, Please.
Thanks,
regards,
Krn
Andrew Forsyth
Richard Lighton wrote:
> This is hardly a new idea. The same sort of system has been used
> to determine the speed of baseball pitches as long as I've been
> watching baseball (over 20 years) and has been used for issuing
> traffic tickets for more than thirty.
I'd be interested to know why the bowling speed radar at Lords last year
(Eng-Pak) was so bad. In other sports (as mentioned above) it does
indeed seem to make sense, certainly comparatively (ie X is faster than
Y), but the one at Lords (called Sniper I think) showed really wierd
stuff. I think Mulally was supposedly consistently faster than Waqar, or
something silly like that. Was it just set up incorrectly or does the
fact that the ball pitches in cricket confuse it?
Andrew Forsyth
Richard Lighton
In article <32E145...@compuserve.com>,
because the batter is much closer to places where a radar gun can be used.
There are hand-held ones available, used by many teams and often operated
from the dugout.
I have no idea what might have been wrong at Lord's. Setup is most likely.
But some calibration before the match with a bowling machine should be
possible.
Simon
> > I'd be interested to know why the bowling speed radar at Lords last year
> > (Eng-Pak) was so bad. In other sports (as mentioned above) it does
> > indeed seem to make sense, certainly comparatively (ie X is faster than
> > Y), but the one at Lords (called Sniper I think) showed really wierd
> > stuff. I think Mulally was supposedly consistently faster than Waqar, or
> > something silly like that. Was it just set up incorrectly or does the
> > fact that the ball pitches in cricket confuse it?
> >
> Setting up a radar gun for baseball must be much easier than for cricket,
> because the batter is much closer to places where a radar gun can be used.
> There are hand-held ones available, used by many teams and often operated
> from the dugout.
Well even in baseball there are significant problems. I remember last
year they were using a gun in association with a silicon graphics display
to show the path and speed of the ball at various points along its flight
(during Yankees games). Several of the graphics showed the ball SPEEDING
UP in midair as it approached the batter !!!
Simon
Bob Dubery
gp...@yebo.co.za (Graham Jewitt) wrote:
>At Newlands, the device, a white box 700mm wide and 300mm high standing on a
>white tripod, was virtually
>invisible to spectators as it was placed in front of the white sidescreen.
This is interesting because at the Wanderers the device is not behind
the bowler but at an angle (about 30 deg ?) to the wicket. I would
expect that this factor would reduce the accuracy of the results
shown.
Bob Dubery
Richard Scott
lj...@anat.uct.ac.za
What about a Topspinner (?) - here the ball gains pace of the wicket due
to its spinning action (ie angular momentum being converted into linear
momentum on contact with the pitch).
I'm not sure, but it may even be possible for a fast bowler to gain
speed when the ball pitches - if there is a way of converting the energy
which would normally determine the bounce , into propelling the ball
forward instead (?).
Ian Jennings
Simon wrote:
> Well even in baseball there are significant problems. I remember last
> year they were using a gun in association with a silicon graphics display
> to show the path and speed of the ball at various points along its flight
> (during Yankees games). Several of the graphics showed the ball SPEEDING
> UP in midair as it approached the batter !!!
You're sure Trevor Quirk wasn't responsible for this? It sounds like
his "the ball speeds up when Andrew Hudson hits it" and "McMillan bowls
slower than Donald but hits the bat harder" comments.
Ian
phil. Felton
In article <Pine.GSO.3.93.970120120722.15952F-100000@uhunix5>, Richard
Scott <rsc...@hawaii.edu> wrote:
I'd be surprised if it works this way, the more normal way would be to use the
Doppler principle by which the change in frequency of the reflected radar
signal is directly related to the velocity of the moving object from which it
was reflected. The difficulty in cricket compared to baseball is the increased
range at which one has to make the measurement. The installation does not have
to be in direct line of fire to be accurate as this effect can be compensated
for. All deliveries will slow down as they approach the batsman due to drag.
Phil.
Jim Garner
phil. Felton (fel...@phoenix.princeton.edu) writes:
> In article <Pine.GSO.3.93.970120120722.15952F-100000@uhunix5>, Richard
> Scott <rsc...@hawaii.edu> wrote:
This thread has reached an intersting point: how much does a ball slow
down during the 18-19 yards of flight?
Various writers in this group have attributed the slowing down of the ball
to the late-swing effect.
Me, I've always been a bit sceptical about this explanation. I can't
quite believe that a ball in flight would slow down appreciably over this
small distance. Sure an artillery shell has a wonky parobala, but that's
over several miles. Eighteen Yards? Hmmm!
So does anybody know whether these radar guns show a change in speed
during the trajectory of a cricket ball, and how much? It could be
fairly important.
Mark you, science doesn't have all the answers. Geoff Boycott, in his
commentary last year from Trent Bridge, said that every batsman knows
that the ball swings more when the sun is clouded, no matter what the
scientists say. I'm inclined to trust Sir Geoff more than the very
knowlegable and talented engineers who discuss these matters here.
--
Jim Garner, Freelance editor, writer and dogsbody
an...@freenet.carleton.ca http://www.ncf.carleton.ca/~an410
(613) 526-4786; 759B Springland, Ottawa, ON K1V 6L9
LET GOD DRY THE DISHES
Your email
>
>
>I'm not an expert myself, but it occurs to me that gravity should help it
>accelerate actually, on the "down" leg, which is usually most of the delivery;
>say 80% +, except the "bouncer" perhaps. After deflection i.e. bouncing on the
>pitch, gravity slows it and parabolic motion come into play. Considering the
>distance left to be travelled to the bat - not much lost there yet; but by the
>time it gets to keeper, it's a lot more manageable.
>
>S.G.Smith (Kingston, Jamaica)
Eamon Hannan
A scientific journal I read once said that the seam might lift more on a
humid day causing more swing - I fancy that David Frith may have detailed
the discussions about speed when it was all the rage in the seventies in
the Lilian Thomson era.
Jim Garner <an...@FreeNet.Carleton.CA> wrote in article
<5cen3s$1...@freenet-news.carleton.ca>...