Golf Game Computing System (US Patent 3,598,976)
United States Patent
(11) 3,598,976
{72} Inventors Jack A. Russell;
Bradford J. Baldwin, both of Muskegon,
Mich.
[21] Appl. No. 861,944
(22] Filed Sept. 29, 1969
Division of Ser. No. 588,922, Oct. 24, 1966,
Pat. Ne. 3,513,707.
{45} Patented Aug. 10, 1971
(73] Assignee Brunswick Corporation
[54] GOLF GAME COMPUTING SYSTEM
13 Claims, 22 Drawing Figs.
[$2] USC ccececcecccceteteces esses seeeesseen 238/181,
273/87, 273/176
ESS A © Senn G06q 7/48,
A63b 67/02
{50} Fleld of Search............. sevecsstssasevensusteteeee 235/151,
150.27, 189, 186, 61.5; 273/87, 87 A—H, 176,
176 A—L, 181 A—K, 183 A—E, 184 A, 185 A,
185B
(56] References Cited
UNITED STATES PATENTS
2,894,753 7/1959 Simjian...............0...58 273/185 A
3,091,466 5/1963 Speiser.......... 235/151 X
3,160,011 12/1964 Ogden... coe 273/181 GX
3,309,927 3/1967 Ferranti.......... 273/185 AX
FOREIGN PATENTS
721,170 11/1965 Canada... ee 273/185 A
Primary Examiner— Malcolm A. Morrison
Assistant Examiner—Joseph F. Ruggiero
Attorney—Hofgren, Wegner, Allen, Stellman & McCord
ABSTRACT: A computer system for use in indoor golf games.
The system includes data acquisition means for obtaining data
relative to the trajectory of a golf ball hit from a tee, a means
for receiving the trajectory information and for providing a
signal whose magnitude is representative of the initial velocity
of the golf ball; a means for decaying the magnitude of the
‘agra at a predetermined rate to provide a second signal
w magnitude is representative of the instantaneous
velocity of a golf ball at any corresponding point in the
theoretical time of flight of the golf ball; and a display device
for utilizing the second signal to provide information relative
to the theoretical free flight trajectory of the golf ball to a
golfer.
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1
GOLF GAME COMPUTING SYSTEM
CROSS-REFERENCE
This application is a division of our copending application
Ser. No. 588,922, now U.S. Pat. No. 3,513,707, filed Oct. 24,
1966 and entitled “Golf Game Computing System.”
BACKGROUND OF THE INVENTION
A number of attempts have been made to provide indoor
golf games utilizing computer systems for computing the
theoretical free flight trajectory of a golf ball struck by a golfer
and which is intercepted before it travels a significant
distance. Such games have not enjoyed a large degree of com-
mercial success because heretofore they have not been Capa-
ble of providing a golfer with all pertinent information relative
to his shot. For example, in one commercialized version of an
indoor golf game, it is considered that a ball will always follow
a predesignated trajectory independently of the angle of eleva-
tion or azimuth of the shot and the trajectory is lengthened or
shortened only in a manner dependent upon the initial
velocity of the shot. In all versions known to be commercial-
ized, none take into account the factor of spin that could
produce a hook or a slice. While systems that take into ac-
count the factor of spin have been Proposed, none have been
commercialized.
Furthermore, the systems proposed and/or commercialized
neglect a multitude of other factors that influence the trajecto-
Ty of a golf ball and by doing so are incapable of realistically
portraying to a golfer a simulation of the trajectory of the shot
that would closely follow the trajectory that would be ob-
served by a golfer if he were to hit the same shot on a golf
course.
SUMMARY OF THE INVENTION
The principal object of the invention is to provide a new and
improved computer system for indoor golf games that max-
imizes the realism of the results of a shot and displays the
results to a golfer.
More specifically, it is an object of the invention to provide
such a new and improved computer system utilizing an analog
computer.
Another object of the invention is the provision of a com-
puter for an indoor golf game that includes means for deter-
mining the initial velocity of a ball struck from a tee, a means
for utilizing the determined initial velocity to determine total
instantaneous velocity of the ball at any point during its
theoretical flight in a manner that reflects the effect of drag on
a ball, and a display device utilizing instantaneous velocity in-
formation to display characteristics of the theoretical free
flight trajectory toa golfer.
Still another object is the provision of a computer system
such as that set forth in the preceding paragraph wherein the
means for determining total instantaneous velocity include the
decaying means for decaying a characteristic of a signal
representing initial velocity at a predetermined rate to provide
a second signal having a characteristic which is representative
of the instantaneous velocity of a golf ball at any correspond-
ing point in its theoretical flight of a golf ball.
A further object is the provision in a computing system of a
means for effecting a change in the rate of decay of the instan-
taneous velocity representing a characteristic of the second
signal when the same is indicative of a ball velocity such that
air flow about a ball in flight would change the laminar flow.
A still further object is the provision in a Computing system
such as that set forth in the Preceding paragraph and having a
bounce and/or roll generating circuit of means for effecting an
increased decay rate when it is determined that the theoretical
free flight of the trajectory of the ball would bring the same
into contact with the ground as by bounding or rolling
thereon.
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A still further object of the invention is the provision of a
computing system such as that set forth above wherein the
decaying means are comprised of electrical elements and in-
clude first and second resistive circuits each arranged to have
the second signal applied thereto with the first circuit being
continually conductive and the second circuit including means
for sensing the magnitude of the second signal and for
precluding the second circuit from conducting when the mag-
nitude of the second signal drops below a predetermined level
to effect a change in the rate of decay when the computed in-
stantaneous velocity drops below a predetermined value to ac-
count for the change in decay rate when the air flow about a
golf ball in flight changes to laminar flow.
Further objects and advantages of the invention will
become apparent from the following specification taken in
conjunction with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevation of a room housing a computing
system made in accordance with the invention;
FIG. 2 is a schematic illustrating the computer-triggering
and initial velocity computing system;
FIG. 3 is comprised of FIG. 3A and FIG. 3B, the latter being
adapted to be placed to the tight of the former, and is a sche-
matic illustrating a trigonometry matrix for providing informa-
tion relative to the initial angle of elevation of the shot;
FIG. 4 is comprised of FIG. 4A and FIG. 4B, the latter being
adapted to be placed to the right of the former, and is a sche-
matic of the computer circuitry;
FIG. 5 is comprised of FIG. SA and FIG. SB, the latter being
adapted to be placed to the right of the former, and is a sche-
matic of a trigonometry matrix for providing information rela-
tive to the angle of the shot with regard to the azimuth,
FIG. 6 is a planar plan view of a Printed circuit used in the
spin detector of the instant invention;
FIG. 7 is a side elevation of a form used to support the
printed circuit illustrated in FIG. 6 and further illustrates other
elements of the spin detector and electrical connections to the
computer;
FIG. 8 is a schematic of a spin determining matrix used in
conjunction with the spin detector illustrated in FIGS. 6 and 7;
FIG. 9 is a schematic of the Circuitry utilized to control a
ball spot projector to illustrate the bouncing of a ball;
FIG. 10 is a schematic of automatic reset circuitry that is
operated in the event the computer is improperly energized;
FIG. 11 is a side elevation of a ball Spot projector;
FIG. 12 is an enlarged front elevation of a portion of the ball
Spot projector;
FIG. 13 is an enlarged side elevation of a portion of the ball
Spot projector with parts shown in section;
FIG. 14 is a front elevation of a Portion of a ball spot projec-
tor with parts shown in section;
FIG. 15 is a bottom view of a
tor mechanism;
FIG. 16 is a plan view of a map of a golf hole that may be
used in playing a game with an apparatus made according to
the invention;
FIG. 17 is a perspective view of a map spot projector system
utilizing the map of FIG. 16 at one Stage of operation;
FIG. 18 is a perspective view illustrating a stage in the
Operation of the map spot projecting system subsequent to
that illustrated in FIG. 17; and
FIG. 19 is a schematic of a control system for driving the
map spot and ball spot projectors with the outputs of the com-
puter.
portion of the ball spot projec-
GENERAL DESCRIPTION
As noted previously, the principal object of the invention is
to provide an indoor game system utilizing a computer that
controls output functions which are made visually apparent to
a golfer and which are designed to give the visual impression
the golfer would have received had he been playing on an ac-
3,598,976
3
tual outdoor golf course. Additionally, the output functions of
the computer are used to provide data for various peripheral
functions required in an indoor golf game.
More specifically, the computer is adapted to be used in a
golf game wherein a tee area is arranged in front of a screen
which may receive projected scenes from a projector
representative of the views as from different portions of a golf
course. The screen is of the penetrable type and behind the
screen is placed spin detecting equipment. In front of the
screen and between the screen and the tee area, other data
acquisition equipment is placed; and the arrangement is such
that when a golfer hits a ball from the tee area, the ball will
travel a relatively short distance, usually less than 30 feet.
After such a distance is traveled, the computer will be pro-
vided with all the necessary information required to perform
its various functions.
A ball spot projector is arranged to project a small spot of
light on the screen, which spot of light simulates a golf ball.
When the golf ball is in flight, the spot of light will be moved
on the screen by the projector under the influence of the com-
puter to illustrate the trajectory of the ball. Means are also
provided so that when the ball spot appears to initially contact
the surface of the golf course as seen on the screen, it will be
caused to bounce and/or roll. The computer includes means
for generating bounce and roll signals which are provided to
the ball spot projector to cause the latter to move the pro-
jected spot to simulate the bouncing and/or rolling of a golf
ball on a fairway or a green, etc.
As mentioned above, spin-detecting equipment is utilized;
and accordingly, during the flight of the ball, the computer
provides the ball spot projector with information relative to
hook or slice such that the projected spot will give the illusion
of a hooking or slicing golf ball.
While the effect of drag on a golf ball in flight is not obvi-
ously perceptible to a golfer, it does have an effect on the
distance that the shot will travel and influences the trajectory
of the ball in flight. The computer includes means for
diminishing the velocity of a ball in accordance with the effect
of drag as will be seen. As a result, the computed distance a
shot would have traveled had it not been intercepted by the
spin detecting equipment very accurately represents the ac-
tual distance it would have traveled on an outdoor golf course.
Furthermore, since the drag information is fed into the ball
spot projector along with other information, the trajectory of
the ball as evidenced by the projected spot of light on the
screen appears to closely simulate that of a ball in flight on an
outdoor golf course.
As is well known, when a golf ball is hit properly by most
clubs, back spin is imparted onto the ball which tends to pro-
vide a lifting force on the golf ball. Of course, the lifting force
is somewhat opposed by gravity. The computer further in-
cludes means for introducing the effects of lift and gravity on
the ball, and the projected spot of light illustrating the trajec-
tory of the ball is controlled accordingly.
The computer also provides information to a meter which
indicates the distance each ball would have traveled had it not
encountered the spin detecting equipment. Obviously, on an
outdoor golf course such a distance can only be estimated; but
in an indoor golf game flexibility is added to the installation by
providing the golfer with distance information. Additionally,
the computer controls an indicator which informs a golfer that
the system is ready to handle the information relative to the
next shot thereby enabling the golfer to hit the next shot. The
computer also provides an indication to the golfer when the
system is not ready to utilize further information such that the
golfer is informed that the next shot should not be played.
Because the system contemplated by the instant invention
provides for hooking and slicing unlike other systems cur-
rently commercially available, it will be appreciated that if a
golfer hooks a shot, the next scene projected on the screen
should be taken from the left side of the fairway or from the
left rough as opposed from the center of the fairway as would
be the case if the golfer hit a straight ball. Accordingly, it is
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necessary to indicate to the golfer which scene should be pro-
jected on the screen before the next shot is played and that the
scene to be selected cannot be chosen merely as a function as
distance. Thus, a map of each hole on a golf course is provided
and the map is divided into a plurality of zones, each zone
representing a scene. In order to indicate to the golfer which
zone his shot would have terminated so as to enable him to
select the next scene, information from the computer is fed to
a second spot projector not unlike the ball spot projector
which is arranged to project a spot of light on the zone on the
map of the golf hole in which the shot terminated thereby
enabling the golfer to select the scene corresponding to that
zone for his next shot.
MATHEMATICS OF THE TRAJECTORY OF A GOLF
BALL
In order to make the projected ball spot on the screen ap-
pear to be a golf ball on an outdoor course, it is necessary to
vary it in three distinct ways. Of course, it must be able to
move vertically or in a Y direction to illustrate the elevation
effect of the shot. It must also be able to be varied horizontally
or in an X direction to illustrate the effect of initial direction
and that of hook or slice. Finally, it should be varied in size to
give the impression of distance in the Z direction. As will be
seen, the ball spot projector is controlled in all three ways.
However, in order to do such, it will be apparent that the
trajectory of a golf ball must be resolved into the three com-
ponents of azimuth, elevation and length.
It will also be apparent that at any given instant, these quan-
tities will vary from their values at another point of time
because the instantaneous velocity of the golf ball is con-
tinually changing. In this respect, it will be noted that the in-
stantaneous velocity in the Y or vertical direction will be posi-
tive and negative at different portions during the trajectory of
a shot. Similarly, if a ball is hooked or sliced, the instantaneous
velocity of the ball in the azimuth or X direction may also be
positive and negative during different portions of the trajecto-
ry depending upon its initial direction with regard to the
azimuth. Only in the case of the distance in the length or Z
direction, will the instantaneous velocity in that direction be
positive or zero. Of course, in any event, the magnitude of the
instantaneous velocities in any direction will be continually
varying.
It has been found that the instantaneous velocity of a golf
ball may be generally considered to follow the equation
V,= Vor Ki [ved
to)
EQUATION (1)
where:
V, is the instantaneous velocity,
¥, is the initial velocity, and
K, is the drag coefficient.
It has been found that the drag coefficient K , varies with
the velocity of the golf ball. For example, when the velocity of
the golf ball is less than 100 feet per second, the air flowing
about the golf ball is in a laminar state and K, is approximately
0.50. However, at velocities greater that 100 feet per second,
the value of K, drops off substantially to about 0.21. While in
actuality, the curve representing the value of K, for any given
velocity does not represent a step function, it has been found
that it is sufficiently linear for the velocities of concern such
that the aforementioned values may be used. The manner in
which the effect of drag is implemented will be seen
hereinafter.
From the foregoing, it will be apparent that the one quantity
necessary to determine the instantaneous velocity V, is the ini-
tial velocity Vy). The manner in which V, is determined will be
described hereinafter.
Since V, may be calculated at any point in the time of trajec-
tory of a golf ball, it will be apparent that it is necessary to
resolve V, into its X, Y and Z components, the X direction
3,598,976
5
being to the right or left of a golfer facing a fairway, the Y
direction being up or down and the Z direction being in the
direction toward the cup. If ©, the angle of elevation of the
shot, is known, it will be appreciated that the velocity in the Y
direction is as follows.
Vij=Vi sing EQUATION (2)
Of course, equation 2 does not represent the effect on the in-
stantaneous velocity in the Y direction caused by gravity or by
lift although it does include the effect of drag. The effect of lift
and gravity will be treated hereinafter.
If B, the angle of the initial direction from the Z or the
length axis, is known, it will be appreciated that the instan-
taneous velocity in the X direction may be determined from
the following equation.
Vi,=V; cos 6 sin B
EQUATION (3)
Here again, it will be apparent that equation 3 does not in-
clude the effect on the instantaneous velocity in the X
direction caused by hook or slice spin. The effect of spin on
the instantaneous velocity in the X direction will be discussed
hereinafter.
Knowing both the angle of elevation and the angle with re-
gard to the azimuth, it will be appreciated that the instantane-
ous velocity in the Z or length direction may be determined by
equation 4 below.
Vi,=Vi cos @ cos B
EQUATION (4)
It will be apparent that equation 4 above, does not take into
account any velocity factors in the Z direction due to lift or
hook or slice spin. In this respect, it has been determined that
the influence of these factors on instantaneous velocity in the
Z direction are relatively insignificant and may be neglected.
Turning now to the effect of lift, it has been determined that
a good approximation of the force acting on the ball due to lift
will be achieved if lift is considered to be a function of the in-
stantaneous velocity acting in a direction normal to the initial
angle of elevation of the ball. Accordingly, the force provided
by lift is treated as follows.
Lift Foree=K,V; EQUATION (5)
where:
K, is a constant.
It will be recognized that the acceleration due to gravity will
be constant and acts in a strictly vertical direction. It is desira-
ble to add vectorily the force of lift and the force of gravity,
and thus lift force must be resolved into its component in the
Y direction. It will then be apparent that the effect on the in-
stantaneous velocity in the Y direction due to the combined
effect of lift and gravity is illustrated by equation 6.
Vi, (due only to lift and gravity=
fi at ist 8y=0 after t=0
t
~0 (K2V; cos o—g)dt
EQUATION (6)
where:
g is the constant force of gravity.
It will be appreciated that once a ball has contacted the
ground for the first bounce in its trajectory, the kinetic energy
imparting a lift spin will be substantially totally dissipated. Ac-
cordingly, after the first bounce of a ball, the factor of lift may
be disregarded, and thus in equation 6 above the upper limit of
the integral is the time at the first time when the Y distance is
equal to zero occurring any time after 0. Hereinafter, sucha
time will be represented as 18.
While lift may be disregarded after the first bounce, it will
be apparent that gravity should not be. Accordingly, it is
necessary to provide for gravity during bouncing of the ball. It
is also necessary to consider the velocity in the Y direction
after bounce due to the bouncing of the ball. It has been found
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a good approximation of the velocity in the Y direction during
bounce and exclusive of gravity is met by the quantity V; sin 0.
The effect of gravity on the instantaneous velocity in the Y
direction may be set forth as follows.
Vi, (due only to gravity during bouncing) = —(Vj,)}2?B
EQUATION (7)
where:
Vin is the instantaneous velocity in the Y direction due to
force of gravity and which is effective from the time of the first
bounce (f=18) until the time when the ball comes totally to
rest (t=R).
By combining equation 2, 6 and 7 above, it will be apparent
that the distance in the Y direction may be expressed as fol-
lows:
Vi
¢
=R
8,=f"- [v. sin 0— (Vi, )izhs Jat
+f (K2V;, cos é—g) dt?
EQUATION (8)
For the limits shown in equation 8, it will be apparent that
the distance in the Y direction S, will be zero. However, it will
be apparent that the distance in the Y direction at any instant
during the flight of the ball may be determined by merely
changing the upper limits of the various expressions to reflect
the time at the instant the Y distance is desired.
Reflecting a moment on the development of equation 8, it
will be seen that a number of factors are included to provide
realism in the game. For example, it will be recalled that V; in-
cludes an adjustment for drag and the energy loss due to con-
tact with the ground during the bouncing of the ball. Similarly,
the expression K,V, cos @ provides for the effect of lift while
the factors V; and g take into consideration the effect of
gravity at different portions of the flight. The effect of bounce
or roll resides in the factor V, sin @ and its combination with
the gravity factor Vi,
Turning now to the distance in the Z direction S,, it will be
appreciated that this quantity may be obtained merely by in-
tegrating the expressions set forth in equation 4 from time is
equal to zero until the time at which the ball comes to rest.
Thus, the distance in the Z direction is indicated in equation 9
below.
t=R
0 V; cos @cos B
EQUATION (9)
S.=
t=
Here again, it will be apparent that the distance in the Z
direction at any instant during the flight of the ball may be
found by choosing the upper limit of the integral appropriate-
ly.
The foregoing leaves for consideration only the effect of
hook or slice spin in the X direction. By means of a matrix that
measures the deviation of a golf ball from a no spin trajectory,
the force applied to the ball due to the effect of side spin is
determined. For purposes of the instant application, the side
spin force may be considered to be determined imperically
and the manner in which this is accomplished will be
described in detail hereinafter. Once the force is obtained, it
will be appreciated that its effect on the velocity in the X
direction may be determined by integrating the force quantity
as indicated in equation 10.
=R
V;,(due only to spin) ={r (side spin force) dé
_. EQUATION (10)
3,598,976
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By combining equations 3 and 10 above and integrating, the
total distance in the X direction at any instant of time during
the flight of the golf ball may be determined. Thus, equation
11 sets forth an expression for the distance in the X direction.
g t=B,, ésin B t=R ide spin f. dt
=e. ; cos @ sin +r (side spin force)
EQUATION (11)
Again, it will be appreciated that the distance in the X
direction at any instant during the flight of the golf ball may be
determined merely by adjusting the upper limits of the in-
tegrals involved appropriately.
IMPLEMENTATION
in order to compute the quantities as set forth in equations
1—1!1 under the preceding heading, an analog computer is
used. Through the use of the analog computer, the distance in
each of the X, Y and Z directions is determined instantane-
ously at virtually every instant of time during the flight of the
golf ball. The exception to the foregoing statement resides in
the very early portion of the flight of the golf ball, i.e. about
the first 30 feet of its flight, during which time the data, name-
ly, the initial velocity V,, the elevation angle @, the azimuth
angle B and the displacement, if any, of the actual flight of the
ball from a theoretical no side spin trajectory is acquired.
Once these quantities are obtained, the X, Y and Z distances
are continually computed throughout the flight of the ball, and
a perceptible indication of each quantity is provided by the
position of the projected ball spot on the screen by a projector
which is operated in accordance with the magnitude of the
quantities.
SPECIFIC DESCRIPTION
Environment
An exemplary embodiment of the invention in the environ-
ment of an indoor golf game is illustrated in FIG. 1. Ina room
having a floor 100, an elevated platform 102 is placed. A point
104 on the platform designates the point at which a ball is to
be placed and driven by the golfer. A penetrable screen 106 is
provided in front of the point 104 and is arranged to have golf
balls driven thereat. The penetrable screen 106 preferably is
of the type described in the copending application of Cornell
et al., Ser. No. 540,917, filed Apr. 7, 1966, now U.S. Pat. No.
3,420,524, and assigned to the same assignee as the instant in-
vention. Behind the penetrable screen 106 is an ellipsoidal
shell 108 which receives golf balls driven from the tee point
104 through the screen 106 and rebounds the golf ball so
driven to a spin detector 110.
The point 104, the shell 108 and the spin detector 110 are
preferably arranged in the manner set forth in the copending
application of Cornell and Uecker, Ser. No. 470,363, filed
July 8, 1965, now U.S. Pat. No. 3,364,751, and assigned to the
same assignee as the instant invention. For details of the
specific construction, reference may be had to said Cornell
and Uecker application. For the purposes of the instant disclo-
sure, it is sufficient to say that the arrangement is such that a
ball hit from the point 104 and striking the shell 108 will
rebound to very nearly the same point on the spin detector
110 regardless of its angle with relation to the azimuth or its
elevational angle if the ball has no spin. If the ball has spin, it
will deviate from such a point an amount proportional to its
spin and the deviation is measured for purposes of determin-
ing side spin.
For purposes of determining the initial velocity V. and the
elevational angle 6, a photocell array, generally designated
112, is provided. The photocell array 112 consists of 20
photocells 114 that are placed adjacent one wall of the room
in which the game is to be played. Adjacent the opposite wall
of the room are 20 corresponding masked light sources that
are aligned with the corresponding masked light sources that
are aligned with the corresponding ones of the photocells 114.
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The overall arrangement is such that a ball hit from the point
104 will break the beam of light passing from one or two of the
light sources to one or two of the photocells. In this respect,
the 20 beams of light from the light sources to the photocells
114 are arranged arcuately about the point 104 in a semicircle
having a radius of about 4 feet. Additionally, when consider-
ing a horizontal plane encompassing the point 104, the
photocells and their corresponding light sources are arranged
arcuately about the point 104 with their centers in 2-degree
increments from a point 1° above the horizontal plane to a
point 39° above the horizontal plane. Thus, if a ball were to
leave the point 104 at a 1° angle with respect to the horizontal
plane, it will be apparent that it would break the beam of light
between the lowermost photocell 114 and its associated light
source. As will be seen, the shading of a photocell is used to
provide the required information for determining the angle of
elevation of the shot.
As mentioned above, the photocell array 112 is also used in
determining the initial velocity V,. Since the straightaway
distance between the point 104 and the photocells 114 is
known, if the time at which the ball leaves the point 104 is
known, and the time at which the ball breaks one of the beams
of light from the light sources to the photocells 114 is known,
it will be apparent that the velocity can be computed. In order
to determine when the ball leaves the point 104, a microphone
116, or other vibration sensitive element, is placed adjacent
the point 104 and will pick up the sound of a golf club hitting a
ball at the point 104 which, of course, will occur when the ball
leaves the point 104. Additionally, to prevent false triggering
of the velocity determining circuit, in the ceiling 118 of the
room, there is placed a source of light 120 which is focused
upon the point 104. Adjacent the source of light 120 is a
photocell 122 which is arranged to receive light reflected from
the source 120 by a ball at the point 104. Of course, when the
ball is struck and moves away from the point 104, there will be
nothing at the point 104 to reflect the light; and accordingly,
the photocell 122 will also detect when the ball leaves the
point 104.
At first blush, it may appear that the use of both the
microphone 116 and the light source 120 and photocell 122
arrangement would be redundant in that either one alone
could be utilized. However, the arrangement just described is
particularly advantageous in contrast to prior art systems
which use either a microphone system or a photocell system
but not both in that, as is well known, many golfers prefer to
take practice swings before they actually hit the ball. If a
golfer were to take a practice swing and the club were to en-
counter the upper surface of the platform 102, it would be ap-
parent that the microphone 116 would respond thereto to in-
itiate operation of the velocity determining circuit when in
fact such would not be the case.
Similarly, in the prior art systems where photocells are used,
it will be appreciated by those skilled in the art that in most
such instances the photocells are used to received horizontally
projected light beams. In such an instance, it will be apparent
that a practice swing could break a horizontally projected light
beam and cause false triggering if only such a photocell trig-
gering were to be used. In the instant system, however, means
are provided to be described hereinafter which preclude the
energization of the velocity determining circuit unless the light
beam from the source 120 to the photocells 122 is broken and
the microphone 116 simultaneously registers the sound of the
club hitting the ball.
In order to determine the angle of the shot with regard to
the azimuth, a second photocell array 124 is provided. The
photocell array 124 is mounted on the floor 100 of the room,
and there is also provided an array of aligned masked light
sources 126 mounted on the ceiling of the room directly above
the photocell array 124. The photocell array 124 consists of
46 photocells 128 which are arranged transversely to the line
at which a ball hit straight from the point 104 would take,
there being 23 such photocells on each side of the line.
3,598,976
9
The centers of the photocells 128 are spaced apart a
distance equal to the diameter of a golf ball. Thus, it will be
apparent that the spacing of the photocells 128 does not cor-
respond to an integral, angular increment with regard to the
point 104, but this difference is taken into consideration in the
arrangement of the azimuth trigonometry matrix as will be
seen. As a result of the just described construction, it will be
apparent that the angle with respect to the azimuth of a golf
ball struck at the point 104 may be obtained.
As mentioned previously, it is desirable to provide a projec-
tion of a scene on a golf course onto the screen 106. Ac-
cordingly, a projection booth 130 is suspended from the ceil-
ing 118 to project a selected image of a scene on a golf course
onto the screen 106. The instant invention contemplates the
use of a projector such as that described in the copending ap-
plication of Pratt et al., Ser. No. 574,218, filed Aug. 22, 1966,
and assigned to the same assignee of the instant application,
although another projector could be used. In order to
facilitate realism, it is desirable, however, that some means
identical or similar to those disclosed in the aforementioned
application of Pratt et al. for accurately aligning the projected
image at a predetermined position on the screen be employed.
The projection booth 130 also houses a ball spot projector
which projects a spot of light on the screen 106 to simulate the
trajectory of a golf ball relative to the scene projected on the
screen 106, Finally, the projector housing 130 also supports a
second spot projector 132 which is utilized to project a spot of
light downwardly onto a plotting table 134. The spot of light
projected from the projector 132 is directed onto a map (not
shown in FIG. 1) to illustrate where the flight of the ball would
have terminated on the golf hole by illustrating the point of
termination on the map of the golf hole. The plotting table 134
additionally may support a console 136 which houses the con-
trols for the scene projector and, if desired, the controls for an
automatic lie material selecting device such as that disclosed
in the copending application of Anderson, Ser. No. 545,411
filed Apr. 26, 1966, and assigned to the same assignee as the
instant application.
Finally, a third source of light 138 is mounted on the ceiling
118 of the room. The third source of light 138 may be
clustered in a triangular arrangement with the light source 120
and the photocell 122. By means to be described hereinafter,
when the computer is not ready to digest the information for a
succeeding shot, the light 138 is energized while the light 120
is deenergized. By making the light source 138 project a beam
of light of a color different from that projected by the tight
source 120; and by deenergizing the source of light 120 when-
ever the light source 138 is energized, it will be appreciated
that an arrangement is provided that will preclude deenergiza-
tion of the pho