U.S. patent application number 09/765691 was filed with the patent office on 2002-07-25 for system and method for measuring a golfer's ball striking parameters.
Invention is credited to Manwaring, Scott R..
Application Number | 20020098898 09/765691 |
Document ID | / |
Family ID | 25074232 |
Filed Date | 2002-07-25 |
United States Patent
Application |
20020098898 |
Kind Code |
A1 |
Manwaring, Scott R. |
July 25, 2002 |
System and method for measuring a golfer's ball striking
parameters
Abstract
A system (20) for capturing and analyzing golf club information
and golf ball information during and after a golfer's swing is
disclosed herein. The golf club information includes golf club head
orientation, golf club head velocity, and golf club spin. The golf
club head orientation includes dynamic lie, loft and face angle of
the golf club head. The golf club head velocity includes path of
the golf club head, attack of the golf club head and downrange
information. The golf ball information includes golf ball velocity,
golf ball launch angle, golf ball side angle, golf ball speed
manipulation and golf ball orientation. The golf ball orientation
includes the true spin of the golf ball, and the tilt axis of the
golf ball which entails the back spin and the side spin of the golf
ball. The system includes camera units (26 and 28), a trigger
device (30) and a computer (22).
Inventors: |
Manwaring, Scott R.;
(Carlsbad, CA) |
Correspondence
Address: |
CALLAWAY GOLF COMPANY
Attention; MICHAEL A. CATANIA
2285 Rutherford Road
Carlsbad
CA
92008-8815
US
|
Family ID: |
25074232 |
Appl. No.: |
09/765691 |
Filed: |
January 19, 2001 |
Current U.S.
Class: |
473/151 |
Current CPC
Class: |
A63B 2220/806 20130101;
A63B 24/0003 20130101; A63B 24/0021 20130101; A63B 2220/05
20130101; A63B 69/3658 20130101; A63B 2220/807 20130101; A63B
2024/0031 20130101; A63B 69/36 20130101 |
Class at
Publication: |
473/151 |
International
Class: |
A63B 069/36 |
Claims
I claim as my invention:
1. A method for simultaneously measuring the golf club properties
and the golf ball properties during a golfer's striking of a golf
ball, the method comprising: swinging a golf club toward a teed
golf ball; activating a detector as the golf club is swung toward
the teed golf ball, the detector transmitting an estimated golf
club head speed to an imaging system, the imaging system capable of
compiling a plurality of exposures to generate a frame; taking a
first plurality of exposures of the golf club head prior to the
golf club head impacting the teed golf ball, the first plurality of
exposures having a first time interval between exposures; striking
the teed golf ball with the golf club; taking a second plurality of
exposures of the golf ball after the golf ball has been struck by
the golf club head, the second plurality of exposures having a
second time interval between exposures, the second time interval
different than the first time interval; generating a frame that
includes the first plurality of exposures of the golf club head
prior to impact with the teed golf ball and the second plurality of
exposures of the golf ball after impact with the golf club head;
wherein the method provides measurements of the golf club head and
of the launched golf ball.
2. The method according to claim 1 wherein first time interval for
the first plurality of exposures is shorter than second time
interval for the second plurality of exposures.
3. The method according to claim 1 wherein first time interval for
the first plurality of exposures ranges from 750 microseconds to
2000 microseconds, and the second time interval for the second
plurality of exposures is greater than the first time interval.
4. The method according to claim 1 wherein the imaging system
comprises a first camera and a second camera.
5. The method according to claim 1 wherein the frame comprises at
least three exposures of the first plurality of exposures, and at
least three exposures of the second plurality of exposures.
6. The method according to claim 1 wherein the measurements of the
golf club comprise golf club head orientation, golf club head spin
and golf club head velocity, and the measurements of the golf ball
comprise the golf ball velocity, the golf ball launch angle, the
golf ball side angle, the golf ball orientation and the golf ball
speed.
7. The method according to claim 1 wherein the estimated golf club
head speed is utilized to determine the first time interval of the
first plurality of exposures and the second time interval of the
second plurality of exposures.
8. The method according to claim 1 wherein each of the first
plurality of exposures have a first exposure time, and each of the
second plurality of exposures have a second exposure time, wherein
the second exposure time is greater than the first exposure
time.
9. The method according to claim 1 wherein a laser is utilized to
activate the detector as the golf club is swung toward the teed
golf ball.
10. A system simultaneously measuring the golf club properties and
the golf ball properties during a golfer's striking of a golf ball,
the system comprising: a first camera and a second camera, each of
the first and second cameras focused toward a predetermined field
view; a golf club having at least one light contrasting area
thereon; a golf ball teed within the predetermined field of view; a
detector disposed prior the teed golf ball along a path of a golf
club swing, the detector capable of estimating the golf club speed;
means for calculating a first time interval between a first
plurality of exposures of the golf club and a second time interval
between a second plurality of exposures of the launched golf ball
based on the estimated golf club speed; and means for determining
the golf club swing properties and golf ball launch properties
based on an image frame generated by the first and second cameras,
the image frame comprising the first plurality of exposures and the
second plurality of exposures.
11. The system according to claim 10 further comprising a first
flash device for the first camera and a second flash device for the
second camera.
12. The system according to claim 10 wherein the detector is a
laser detector.
13. The system according to claim 10 wherein the detector is an
audible detector.
14. The system according to claim 10 wherein the golf club has
three highly reflective markers thereon.
15. The system according to claim 10 wherein the first time
interval of the calculating means is less than the second time
interval of the calculating means.
16. A method for simultaneously measuring the golf club properties
and the golf ball properties during a golfer's striking of a golf
ball, the method comprising: swinging a golf club toward a teed
golf ball; triggering a detector as the golf club is swung toward
the teed golf ball, the detector transmitting an estimated golf
club head speed to an imaging system, the imaging system capable of
compiling a plurality of exposures to generate a frame; taking a
first plurality of exposures of the golf club head prior to the
golf club head impacting the teed golf ball, the first plurality of
exposures having a first time interval for each exposure; striking
the teed golf ball with the golf club; taking a second plurality of
exposures of the golf ball after the golf ball has been struck by
the golf club head, the second plurality of exposures having a
second time interval for each exposure, the second time interval
different than the first time interval; generating a frame that
includes the first plurality of exposures of the golf club head
prior to impact with the teed golf ball and the second plurality of
exposures of the golf ball after impact with the golf club head;
wherein the method provides measurements of the golf club head and
of the launched golf ball.
17. The method according to claim 16 wherein first time interval
for the first plurality of exposures is less than second time
interval for the second plurality of exposures.
18. The method according to claim 16 wherein first time interval
for the first plurality of exposures ranges from 10 microseconds to
20 microseconds, and the second time interval for the second
plurality of exposures is greater than the first time interval.
19. The method according to claim 16 wherein the imaging system
comprises a first camera and a second camera.
20. The method according to claim 16 wherein the frame comprises at
least three exposures of the first plurality of exposures, and at
least three exposures of the second plurality of exposures.
21. A method for simultaneously measuring the golf club properties
and the golf ball properties during a golfer's striking of a golf
ball, the method comprising: swinging a golf club toward a teed
golf ball; triggering a detector as the golf club is swung toward
the teed golf ball, the detector transmitting an estimated golf
club head speed to an imaging system, the imaging system capable of
compiling a plurality of exposures to generate a frame; taking a
first plurality of exposures of the golf club head prior to the
golf club head impacting the teed golf ball, the first plurality of
exposures having a first exposure intensity; striking the teed golf
ball with the golf club; taking a second plurality of exposures of
the golf ball after the golf ball has been struck by the golf club
head, the second plurality of exposures having a second exposure
intensity, the second exposure intensity different than the first
exposure intensity; generating a frame that includes the first
plurality of exposures of the golf club head prior to impact with
the teed golf ball and the second plurality of exposures of the
golf ball after impact with the golf club head; wherein the method
provides measurements of the golf club head and of the launched
golf ball.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] The present invention relates to a system and method for
measuring a golfer's launch parameters during a golf swing. More
specifically, the present invention relates to a system and method
for measuring club head information and golf ball information
before and after impact of the golf club with the golf ball.
[0005] 2. Description of the Related Art
[0006] For over twenty-five years, high speed camera technology has
been used for gathering information on a golfer's swing. The
information has varied from simple club head speed to the spin of
the golf ball after impact with a certain golf club. Over the
years, this information has fostered numerous improvements in golf
clubs and golf balls, and assisted golfers in choosing golf clubs
and golf balls that improve their game. Additionally, systems
incorporating such high speed camera technology have been used in
teaching golfers how to improve their swing when using a given golf
club.
[0007] An example of such a system is U.S. Pat. No. 4,063,259 to
Lynch et al., for a Method Of Matching Golfer With Golf Ball, Golf
Club, Or Style Of Play, which was filed in 1975. Lynch discloses a
system that provides golf ball launch measurements through use of a
shuttered camera that is activated when a club head breaks a beam
of light that activates the flashing of a light source to provide
stop action of the club head and golf ball on a camera film. The
golf ball launch measurements retrieved by the Lynch system include
initial velocity, initial spin velocity and launch angle.
[0008] Another example is U.S. Pat. No. 4,136,387 to Sullivan, et
al., for a Golf Club Impact And Golf Ball Launching Monitoring
System, which was filed in 1977. Sullivan discloses a system that
not only provides golf ball launch measurements, it also provides
measurements on the golf club.
[0009] Yet another example is a family of patent to Gobush et al.,
U.S. Pat. Nos. 5,471,383 filed on Sep. 30, 1994; 5,501,463 filed on
Feb. 24, 1994; 5,575,719 filed on Aug. 1, 1995; and 5,803,823 filed
on Nov. 18, 1996. This family of patents discloses a system that
has two cameras angled toward each other, a golf ball with
reflective markers, a golf club with reflective markers thereon and
a computer. The system allows for measurement of the golf club or
golf ball separately, based on the plotting of points.
[0010] Yet another example is U.S. Pat. No. 6,042,483 for a Method
Of Measuring Motion Of A Golf Ball. The patent discloses a system
that uses three cameras, an optical sensor means, and strobes to
obtain golf club and golf ball information.
[0011] Although the prior art has disclosed many useful systems,
the prior art has failed to disclose a system that is capable of
individualizing the calculations based on each individual golfer in
order to provide information on the swing of the golfer and the
launch of the golf ball subsequent to impact with the golf club.
Further, the prior art has failed to disclose a system that allows
for simultaneous imaging and analysis of the pre-impact golf club
and post impact golf ball.
BRIEF SUMMARY OF THE INVENTION
[0012] The present invention provides a method and system for
capturing and analyzing golf club information and golf ball
information during and after a golfer's swing is disclosed herein.
The golf club information includes golf club head orientation, golf
club head velocity, and golf club spin. The golf club head
orientation includes dynamic lie, loft and face angle of the golf
club head. The golf club head velocity includes path of the golf
club head and attack of the golf club head. The golf ball
information includes golf ball velocity, golf ball launch angle,
golf ball side angle, golf ball speed and golf ball orientation.
The golf ball orientation includes the true spin of the golf ball,
and the tilt axis of the golf ball which entails the back spin and
the side spin of the golf ball.
[0013] One aspect of the present invention is a method for
simultaneously measuring the golf club properties and the golf ball
properties during a golfer's striking of a golf ball. The method
begins with the swinging of a golf club toward a teed golf ball.
Next, a detector is activated as the golf club is swung toward the
teed golf ball. The detector transmits an estimated golf club head
speed to an imaging system. The imaging system capable of compiling
a plurality of exposures to generate a frame. Next, a first
plurality of exposures of the golf club head are taken prior to the
golf club head impacting the teed golf ball. The first plurality of
exposures have a first time interval period between exposures.
Next, the teed golf ball is struck with the golf club. Next, a
second plurality of exposures of the golf ball are taken after the
golf ball has been struck by the golf club head. The second
plurality of exposures has a second time interval between
exposures. The second time interval is different than the first
time interval. A frame is generated that includes the first
plurality of exposures of the golf club head prior to impact with
the teed golf ball and the second plurality of exposures of the
golf ball after impact with the golf club head. The method provides
measurements of the golf club head and of the launched golf
ball.
[0014] The first time interval for the first plurality of exposures
may be less than second time interval for the second plurality of
exposures. The first time interval for the first plurality of
exposures may range from 750 microseconds to 2000 microseconds, and
the second time interval for the second plurality of exposures may
be greater than the first time interval. The imaging system of the
method preferably includes a first camera and a second camera. Each
frame preferably includes at least three exposures of the first
plurality of exposures, and at least three exposures of the second
plurality of exposures. The measurements of the golf club include
golf club head orientation, golf club head spin and golf club head
velocity, and the measurements of the golf ball include the golf
ball velocity, the golf ball launch angle, the golf ball side
angle, the golf ball orientation (spin) and the golf ball speed.
The estimated golf club head speed is utilized to determine the
first time interval of the first plurality of exposures and the
second time interval of the second plurality of exposures. The
method preferably uses a laser to activate the detector as the golf
club is swung toward the teed golf ball.
[0015] Another aspect of the present invention is a system for
simultaneously measuring the golf club properties and the golf ball
properties during a golfer's striking of a golf ball. The system
includes a pair of cameras, a golf club, a teed golf ball, a
detector, a calculating means and an analysis means. The first and
second cameras each have a lens focused toward a predetermined
field of view. The golf club has at least one light contrasting
area, and preferably three light contrasting areas. The teed golf
ball is within the predetermined field of view. The detector is
disposed prior to the teed golf ball along a path of a golf club
swing, and it is capable of estimating the golf club speed. The
calculating means calculates a first time interval between a first
plurality of exposures of the golf club and a second time interval
between a second plurality of exposures of the launched golf ball
based on the estimated golf club speed. The analysis means
determines the golf club swing properties and golf ball launch
properties based on an image frame generated by the first and
second cameras which includes the first plurality of exposures and
the second plurality of exposures.
[0016] Another aspect of the present invention is another method
for simultaneously measuring the golf club properties and the golf
ball properties during a golfer's striking of a golf ball. The
method begins with the swinging of a golf club toward a teed golf
ball. Next, a detector is triggered as the golf club is swung
toward the teed golf ball. The detector transmits an estimated golf
club head speed to an imaging system. The imaging system capable of
compiling a plurality of exposures to generate a frame. Next, a
first plurality of exposures of the golf club head are taken prior
to the golf club head impacting the teed golf ball. Each of the
first plurality of exposures has a first exposure intensity. Next,
the teed golf ball is struck with the golf club. Next, a second
plurality of exposures of the golf ball are taken after the golf
ball has been struck by the golf club head. Each of the second
plurality of exposures has a second exposure intensity. The second
exposure intensity is different than the first exposure intensity.
A frame is generated that includes the first plurality of exposures
of the golf club head prior to impact with the teed golf ball and
the second plurality of exposures of the golf ball after impact
with the golf club head. The method provides measurements of the
golf club head and of the launched golf ball.
[0017] Yet another aspect of the present invention is another
method for simultaneously measuring the golf club properties and
the golf ball properties during a golfer's striking of a golf ball.
The method begins with the swinging of a golf club toward a teed
golf ball. Next, a detector is activated as the golf club is swung
toward the teed golf ball. The detector transmits an estimated golf
club head speed to an imaging system. The imaging system capable of
compiling a plurality of exposures to generate a frame. Next, a
first plurality of exposures of the golf club head are taken prior
to the golf club head impacting the teed golf ball. Each of the
first plurality of exposures has a first time interval. Next, the
teed golf ball is struck with the golf club. Next, a second
plurality of exposures of the golf ball are taken after the golf
ball has been struck by the golf club head. Each of the second
plurality of exposures has a second time interval. The second time
interval is greater than the first time interval. A frame is
generated that includes the first plurality of exposures of the
golf club head prior to impact with the teed golf ball and the
second plurality of exposures of the golf ball after impact with
the golf club head. The method provides measurements of the golf
club head and of the launched golf ball.
[0018] Having briefly described the present invention, the above
and further objects, features and advantages thereof will be
recognized by those skilled in the pertinent art from the following
detailed description of the invention when taken in conjunction
with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of the monitoring system of the
present invention.
[0020] FIG. 2 is a schematic isolated side view of the teed golf
ball and the cameras of the system of the present invention.
[0021] FIG. 2A is a schematic isolated side view of the teed golf
ball and the cameras of the system showing the field of view of the
cameras.
[0022] FIG. 3 is a schematic isolated front view of the teed golf
ball, trigger device and the cameras of the system of the present
invention.
[0023] FIG. 4 is an image frame of a golfer's swing and subsequent
launch of a golf ball composed of a multitude of exposures
generated by the system of the present invention.
[0024] FIG. 5 is a partial image frame of a golfer's swing
illustrating a first exposure of the highly reflective points on a
golf club.
[0025] FIG. 5A is a graph of the time (x-axis) versus
activation/deactivation for the exposure of FIG. 5.
[0026] FIG. 5B is a graph of time (x-axis) versus light intensity
of the flash units to demonstrate the activation and deactivation
points for the cameras.
[0027] FIG. 6 is a partial image frame of a golfer's swing
illustrating first and second exposures of the highly reflective
points on a golf club.
[0028] FIG. 6A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 6.
[0029] FIG. 7 is a partial image frame of a golfer's swing
illustrating first, second and third exposures of the highly
reflective points on a golf club.
[0030] FIG. 7A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 7.
[0031] FIG. 8 is a partial image frame of a golfer's swing
illustrating first, second and third exposures of the highly
reflective points on a golf club, and the initial impact golf ball
exposure.
[0032] FIG. 8A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 8.
[0033] FIG. 9 is a partial image frame of a golfer's swing
illustrating first, second and third exposures of the highly
reflective points on a golf club, the initial impact golf ball
exposure, and a first exposure of a golf ball after impact with the
golf club.
[0034] FIG. 9A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 9.
[0035] FIG. 10 is a partial image frame of a golfer's swing
illustrating first, second and third exposures of the highly
reflective points on a golf club, the initial impact golf ball
exposure, and first and second exposures of a golf ball after
impact with the golf club.
[0036] FIG. 10A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 10.
[0037] FIG. 11 is a partial image frame of a golfer's swing
illustrating first, second and third exposures of the highly
reflective points on a golf club, the initial impact golf ball
exposure, and first, second and third exposures of a golf ball
after impact with the golf club.
[0038] FIG. 11 A is a graph of the time (x-axis) versus
activation/deactivation for the exposures of FIG. 11.
[0039] FIG. 12 is an image frame of a low speed driver shot with a
plurality of exposures of the golf club and the golf ball.
[0040] FIG. 13 is an image frame of a high speed driver shot with a
plurality of exposures of the golf club and the golf ball.
[0041] FIG. 14 is a schematic representation of the highly
reflective points of the golf club positioned in accordance with
the first, second and third exposures of the golf club.
[0042] FIG. 15 is an isolated view of a golf ball striped for
measurement using the present invention at a first exposure.
[0043] FIG. 15A is an isolated view of a golf ball striped for
measurement using the present invention at a second exposure with a
partial phantom of the first exposure with vector signs present to
demonstrate calculation of angle .THETA..
[0044] FIG. 16 is a partial image frame from only the first camera
of a golfer's swing illustrating first, second and third exposures
of the highly reflective points on a golf club, and the teed golf
ball before determination of the threshold level on the grey
scale.
[0045] FIG. 17 is a partial image frame from only the second camera
of a golfer's swing illustrating first, second and third exposures
of the highly reflective points on a golf club, and the teed golf
ball before determination of the threshold level on the grey
scale.
[0046] FIG. 18 is a partial image frame from only the first camera
of a golfer's swing illustrating first, second and third exposures
of the highly reflective points on a golf club, and the teed golf
ball after determination of the threshold level on the grey
scale.
[0047] FIG. 19 is a partial image frame from only the second camera
of a golfer's swing illustrating first, second and third exposures
of the highly reflective points on a golf club, and the teed golf
ball after determination of the threshold level on the grey
scale.
[0048] FIG. 20 is a partial image frame from only the first camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball for the first find grouping of the highly reflective
points.
[0049] FIG. 21 is a partial image frame from only the second camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball for the first find grouping of the highly reflective
points.
[0050] FIG. 22 is a partial image frame from only the first camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball for the second find grouping of the highly
reflective points.
[0051] FIG. 23 is a partial image frame from only the second camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball for the second find grouping of the highly
reflective points.
[0052] FIG. 24 is a partial image frame from only the first camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball with repeated points eliminated and results of the
find displayed.
[0053] FIG. 25 is a partial image frame from only the second camera
of a golfer's swing illustrating first, second and third exposures
of the connected highly reflective points on a golf club, and the
teed golf ball with repeated points eliminated and results of the
find displayed.
[0054] FIG. 26 is a chart of the processed final pairs giving the
x, y and z coordinates.
[0055] FIG. 27 is an illustration of the thresholding of the
exposures for the golf ball in flight.
[0056] FIG. 28 is an isolated view of the golf ball to illustrate
determining the best ball center and radius.
[0057] FIG. 29 is a partial flow chart with images of golf balls
for stereo correlating two dimensional points.
[0058] FIG. 30 is a partial image frame of the teed golf ball
exposure and the first, second third and fourth exposures of the
golf ball after impact, along with positioning information.
DETAILED DESCRIPTION OF THE INVENTION
[0059] As shown in FIGS. 1-3, the system of the present invention
is generally designated 20. The system 20 captures and analyzes
golf club information and golf ball information during and after a
golfer's swing. The golf club information includes golf club head
orientation, golf club head velocity, and golf club spin. The golf
club head orientation includes dynamic lie, loft and face angle of
the golf club head. The golf club head velocity includes path of
the golf club head and attack of the golf club head. The golf ball
information includes golf ball velocity, golf ball launch angle,
golf ball side angle, golf ball speed and golf ball orientation.
The golf ball orientation includes the true spin of the golf ball,
and the tilt axis of the golf ball which entails the back spin and
the side spin of the golf ball. The various measurements will be
described in greater detail below.
[0060] The system 20 generally includes a computer 22, a camera
structure 24 with a first camera unit 26, a second camera unit 28
and a trigger device 30, a teed golf ball 32 and a golf club 33.
The system 20 is designed to operate on-course, at a driving range,
inside a retail store/showroom, or at similar facilities.
[0061] In a preferred embodiment, the camera structure 24 is
connected to a frame 34 that has a first platform 36 approximately
46.5 inches from the ground, and a second platform 38 approximately
28.5 inches from the ground. The first camera unit 26 is disposed
on the first platform 36 and the second camera unit 28 is disposed
on the second platform 38. As shown in FIG. 2, the first platform
36 is at an angle .alpha..sub.1 which is approximately 41.3 degrees
relative to a line perpendicular to the straight frame vertical bar
of the frame 34, and the second platform 38 is at an angle
.alpha..sub.2 which is approximately 25.3 degrees relative to a
line perpendicular to the straight frame vertical bar of the frame
34. However, those skilled in the relevant art will recognize that
other angles may be utilized for the positioning of the cameras
without departing from the scope and spirit of the present
invention.
[0062] As shown in FIG. 2A, the platforms 36 and 38 are positioned
such that the optical axis 66 of the first camera unit 26 does not
overlap/intersect the optical axis 68 of the second camera unit 28.
The optical view of the first camera unit 26 is bound by lines 62a
and 62b, while the optical view of the second camera unit 28 is
bound by lines 64a and 64b. The overlap area defined by curves 70
is the field of view of the system 20.
[0063] The first camera unit 26 includes a first camera 40 and
flash units 42a and 42b. The second camera unit 28 includes a
second camera 44 and flash units 46a and 46b. A preferred camera is
a charged coupled device ("CCD") camera available from Wintriss
Engineering of California under the product name OPSIS1300
camera.
[0064] The trigger device 30 includes a receiver 48 and a
transmitter 50. The transmitter 50 is preferably mounted on the
frame 34 a predetermined distance from the camera units 26 and 28.
A preferred trigger device is a laser device that transmits a laser
beam from the transmitter 50 to the receiver 48 and is triggered
when broken by a club swung toward the teed golf ball 32. The teed
golf ball 32 includes a golf ball 56 and a tee 58. Other trigger
devices such as optical detectors and audible detectors may be used
with the present invention. The teed golf ball 32 is a
predetermined length from the frame 34, L.sub.1, and this length is
preferably 38.5 inches. However, those skilled in the pertinent art
will recognize that the length may vary depending on the location
and the placement of the first and second camera units 26 and 28.
The transmitter 50 is preferably disposed from 10 inches to 14
inches from the cameras 40 and 44. The receiver 48 and transmitter
50, and hence the laser beam, are positioned in front of the teed
ball 32 such that a club swing will break the beam, and hence
trigger the trigger device 30 prior to impact with the teed ball
32. As explained in greater detail below, the triggering of the
trigger device 30 will generate a command to the first and second
camera units 26 and 28 to begin taking exposures of the golf club
33 prior to impact with the teed golf ball 32. The data collected
is sent to the computer 22 via a cable 52 which is connected to the
receiver 48 and the first and second camera units 26 and 28. The
computer 22 has a monitor 54 for displaying an image frame
generated by the exposures taken by the first and second camera
units 26 and 28. The image frame 100 is the field of view of the
cameras 40 and 44.
[0065] FIG. 4 is an image frame 100 of a driver shot of a golf
ball. The image frame 100 includes a first plurality of exposures
102, an initial impact golf ball exposure 103 and a second
plurality of exposures 104. The first plurality of exposures
includes images of the golf club 33 prior to striking the teed golf
ball 32. The second plurality of exposures 104 includes images of
the golf ball 56 subsequent to being struck by the golf club 33.
The first plurality of exposures 102 may be distinguished from the
second plurality of exposures 104 by three different factors.
First, the time interval between each of the first plurality of
exposures 102 is shorter than the time interval between each of the
second plurality of exposures 104. Second, the length of time of
each exposure, or more precisely the time that the shutter of the
camera is open, is shorter for each of the first plurality of
exposures 102 than the time of exposure for each of the second
plurality of exposures 104. Third, the intensity of each of the
first plurality of exposures 102 is less than the intensity of each
of the second plurality of exposures 104.
[0066] FIG. 5 is a first exposure 102a only illustrating the three
reflective points on the golf club 33. The points 106a-c are
positioned, respectively, on the shaft on the heel and on the toe
of the golf club 33. As shown in FIG. 5A, the exposure 102a is
taken at time 100 milliseconds from the triggering of the trigger
device 30, and the exposure time is 1 millisecond. The exposure
time need only be 1 millisecond since the reflective points 106a-c
provide such an intense illumination. The Y axis in FIG. 5A, and
similar figures, represents the activation and deactivation of the
cameras 40 and 44. FIG. 5B illustrates the activation and
deactivation of the cameras 40 and 44 on a graph of the intensity
of the flash units 42 and 46 which are charged and increase in
intensity where at point A the cameras 40 and 44 activated and then
deactivated at point D while the intensity of the flash units 42
and 46 is beginning to fall.
[0067] As shown in FIG. 6, a second exposure 102b of the first
plurality of exposures 102 is added to the first exposure 102a of
the first plurality of exposures 102. The second exposure 102b also
only illustrates the three reflective points 106a-c of the golf
club 33. As shown in FIG. 6A, the exposure 102b is taken at time
895.9 milliseconds from the triggering of the trigger device 30,
and the exposure time is 1 millisecond. The time interval between
the first plurality of exposures 102a and 102b is 795.9
milliseconds.
[0068] As shown in FIG. 7, a third exposure 102c of the first
plurality of exposures 102 is added to the first exposure 102a and
second exposure 102b of the first plurality of exposures 102. The
third exposure 102c also only illustrates the three reflective
points 106a-c of the golf club 33. As shown in FIG. 7A, the
exposure 102c is taken at time 1691.8 milliseconds from the
triggering of the trigger device 30, and the exposure time is 1
millisecond. The time interval between the first plurality of
exposures 102b and 102c is 795.9 milliseconds. Thus, the time
interval between the first plurality of exposures 102 is equal, and
approximately 795.9 milliseconds.
[0069] FIG. 8 includes the previous exposures and an initial impact
exposure 103 which is an exposure of the golf club and the golf
ball 32 immediately after impact. As shown in FIG. 8A, the initial
impact exposure 103 is taken at 3681.5 milliseconds from the
triggering of the trigger device 30, and the exposure time is 15
milliseconds. The time interval between the initial impact exposure
103 and the first of the second plurality of exposures 104 allows
for any image noise of the golf club 33 to be captured so not to
"contaminate" the second plurality of exposures 104.
[0070] FIG. 9 is the first exposure 104a of the second plurality of
exposures 104 of the golf ball 56 in flight added to the other
exposures. The first exposure 104a only illustrates the golf ball
56. As shown in FIG. 9A, the exposure 104a is taken at time 6813.5
milliseconds from the triggering of the trigger device 30, and the
exposure time is 15 milliseconds. The exposure time needs to be 15
milliseconds since the golf ball 56 is not as illuminating as the
reflective points 106a-c.
[0071] FIG. 10 is the second exposure 104b of the second plurality
of exposures 104 of the golf ball 56 in flight, added to the other
exposures. The second exposure 104b only illustrates the golf ball
56. As shown in FIG. 10A, the exposure 104b is taken at time 7792.2
milliseconds from the triggering of the trigger device 30, and the
exposure time is 15 milliseconds. The time interval between the
second plurality of exposures 104a and 104b is 978.7
milliseconds.
[0072] FIG. 11 is the third exposure 104c of the second plurality
of exposures 104 of the golf ball 56 in flight, added to the other
exposures. The third exposure 104c only illustrates the golf ball
56. As shown in FIG. 11A, the exposure 104c is taken at time 8770.9
milliseconds from the triggering of the trigger device 30, and the
exposure time is 15 milliseconds. The time interval between the
second plurality of exposures 104b and 104c is 978.7 milliseconds.
Thus, the time interval between the second plurality of exposures
104 is equal, and approximately 978.7 milliseconds, which is a
greater time interval than the time interval between the first
plurality of exposures.
[0073] FIGS. 12 and 13 compare a low speed driver swing to a high
speed driver swing. The triggering of the trigger device 30 by the
golf club 33 is used to determine the speed of golf club swing. As
the golf club 33 breaks the beam, the triggering device 30 sends a
signal with an estimate of the golf club swing speed to the first
and second camera units 26 and 28. The signal tells the first and
second camera units 26 and 28 to take the first plurality of
exposures 102 at certain times and predetermined intervals, to take
the initial impact exposure 103 at a certain time, and to take the
second plurality of exposures 104 of the golf ball 56 in flight at
certain times and predetermined intervals. Thus, the system 20 will
have individual exposure times for each individual golfer's swing
thereby creating a more accurate system 20 to determine the swing
properties of a particular golfer.
[0074] For example, the low swing speed image frame 100 of FIG. 12
has the first plurality of exposures 102a-c taken at 100
milliseconds from the triggering for exposure 102a, 1429.72
milliseconds from the triggering for exposure 102b, and 2759.44
milliseconds from the triggering for exposure 102c. The initial
impact exposure 103 is taken at 5443.88 milliseconds from the
triggering. The second plurality of exposures 104a-d are taken at
9793.93 milliseconds from the triggering for exposure 104a,
10775.15 milliseconds from the triggering for exposure 104b,
11756.37 milliseconds from the triggering for exposure 104c, and
12737.59 milliseconds from the triggering for exposure 104d.
[0075] For comparison, the high swing speed image frame 100 of FIG.
13 has the first plurality of exposures 102a-c taken at 100
milliseconds from the triggering for exposure 102a, 956.38
milliseconds from the triggering for exposure 102b, and 1091.62
milliseconds from the triggering for exposure 102c. The initial
impact exposure 103 is taken at 2083.24 milliseconds from the
triggering. The second plurality of exposures 104a-d are taken at
4091.48 milliseconds from the triggering for exposure 104a, 7335.83
milliseconds from the triggering for exposure 104b, 8799.44
milliseconds from the triggering for exposure 104c, and 9531.25
milliseconds from the triggering for exposure 104d.
[0076] The golf club speed of the low speed swing is 84.5 miles per
hour ("MPH") compared to 114.5 MPH for the high swing speed. The
golf ball speed of the low speed swing is 119.5 MPH compared to
168.0 MPH for the high speed swing. The back spin of the golf club
is 1466 rotations per minute ("RPM") for the low speed swing
compared to 1945 RPM for the high speed swing. The launch angle of
the golf ball for the low speed swing is 17.7 degrees compared to
15.4 degrees for the high speed swing.
[0077] The system 20 may be calibrated using many techniques known
to those skilled in the pertinent art. One such technique is
disclosed in U.S. Pat. No. 5,803,823 which is hereby incorporated
by reference. The system 20 is calibrated when first activated, and
then may operate to analyze golf swings for golfers until
deactivated.
[0078] As mentioned above, the system 20 captures and analyzes golf
club information and golf ball information during and after a
golfer's swing. The system 20 uses the image frame 100 and other
information to generate the information on the golfer's swing. The
golf club 33 has at least two, but preferably three highly
reflective points 106a-c preferably positioned on the shaft, heel
and toe of the golf club 33. The highly reflective points 106a-c
may be inherent with the golf club design, or each may be composed
of a highly reflective material that is adhesively attached to the
desired positions of the golf club 33. The points 106a-c need to be
highly reflective since the cameras 40 and 44 are programmed to
search for two or three points that have a certain brightness such
as 200 out of a grey scale of 0-255. The cameras 40 and 44 search
for point pairs that have approximately one inch separation, and in
this manner, the image of the golf club 33 is acquired by the
cameras for data acquisition.
[0079] As shown in FIG. 14, which is similar to FIG. 7, the first
row of acquired highly reflective points 106a (on the shaft) is
designated series one, the second row of acquired highly reflective
points 106b (on the heel) is designated series two, and the third
row of acquired highly reflective points 106c (on the toe) is
designated series three. The first row is the acquired highly
reflective points 106a from the shaft, the second row is the
acquired highly reflective points 106a from the heel, and the third
row is the acquired highly reflective points 106a from the toe. The
following equation is used to acquire the positioning
information:
d=[(Ptx-Pnx).sup.2+(Pty-Ptny).sup.2 . . . ].sup.1/2
[0080] where d is the distance, Ptx is the position in the x
direction and Pty is the position in the y direction.
[0081] The system 20 may use a three point mode or a two point mode
to generate further information. The two point mode uses V.sub.toe,
V.sub.heel and V.sub.clubtop to calculate the head speed.
V.sub.toe=[(Ptx.sub.3-Ptx.sub.1).sup.2+(Pty.sub.3-Pty.sub.1).sup.2+(Ptz.su-
b.3-Ptz.sub.1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.heel=[(Ptx.sub.3-Ptx.sub.1).sup.2+(Pty.sub.3-Pty.sub.1).sup.2+(Ptz.s-
ub.3-Ptz.sub.1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.clubtop=[V.sub.toe+V.sub.heel] [1/2]
Vy=[(Y.sub.3heel-Y.sub.1heel).sup.2+(Y.sub.3toe-Y.sub.1toe).sup.2].sup.1/2-
[1/2*.DELTA.T)]
Vz=[(Z.sub.3heel-Z.sub.1heel).sup.2+(Z.sub.3toe-Z.sub.1toe).sup.2
].sup.1/2[1/2*.DELTA.T)]
[0082] This information is then used to acquire the path angle and
attack angle of the golf club 33. The Path angle=sin.sup.-1(Vy/[V])
where [V] is the magnitude of V.
[0083] The attack angle=sin.sup.-1 (Vz/[V]), and the dynamic loft
and dynamic lie are obtained by using Series one and Series two to
project the loft and lie onto the vertical and horizontal
planes.
[0084] The two point mode uses the shaft highly reflective point
106a or the toe highly reflective point 106c along with the heel
highly reflective point 106b to calculate the head speed of the
golf club, the path angle and the attack angle. Using the shaft
highly reflective point 106a, the equations are:
V.sub.heel=[(Ptx.sub.3-Ptx.sub.1).sup.2+(Pty.sub.3-Pty.sub.1).sup.2+(Ptz.s-
ub.3-Ptz.sub.1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.shaft=[(Ptx.sub.3-Ptx.sub.1).sup.2+(Pty.sub.3-Pty.sub.1).sup.2+(Ptz.-
sub.3-Ptz.sub.1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.center=1.02 (V.sub.shaft+V.sub.heel)
Vy=[(Y.sub.3heel-Y.sub.1heel).sup.2+(Y.sub.3shaft-Y.sub.1shaft).sup.2].sup-
.1/2[1/(2*.DELTA.T)]
Vz=[(Z.sub.3heel-Z.sub.1heel).sup.2+(Z.sub.3shaft-Z.sub.1shaft).sup.2].sup-
.1/2[1/(2*.DELTA.T)]
[0085] The Path angle=sin.sup.-1 (Vy/[V]) where [V] is the
magnitude of V.
[0086] The attack angle=sin.sup.-1 (Vz/[V]).
[0087] Using the toe highly reflective point 106c, the equations
are:
V.sub.toe=[(X.sub.3-X.sub.1).sup.2+(y.sub.3-y.sub.1).sup.2+(Z.sub.3-Z.sub.-
1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.heel=[(X.sub.2-X.sub.1).sup.2+(y.sub.2-y.sub.1).sup.2+(Z.sub.2-Z.sub-
.1).sup.2].sup.1/2[1/.DELTA.T]
V.sub.clubtop=[V.sub.toe+V.sub.heel][{fraction (1/2)}]
[0088] The path angle=sin.sup.-1(VY.sub.clubtop/[V.sub.clubtop])
where [ V.sub.clubtop] is the magnitude of V.sub.clubtop.
[0089] The attack angle=sin.sup.-1(VZ.sub.clubtop/[V.sub.clubtop])
where [ V.sub.clubtop] is the magnitude of V.sub.clubtop.
[0090] The golf ball 56 information is mostly obtained from the
second plurality of exposures 104. First, the best radius and
position of the two dimensional areas of interest are determined
from the exposures 104. Next, all of the combinations of the golf
ball 56 centers in the exposures 104 are matched and passed through
a calibration model to obtain the X, Y, and Z coordinates of the
golf ball 56. The system 20 removes the pairs with an error value
greater then 5 millimeters to get acceptable X, Y, Z coordinates.
Next, the strobe times from the flash units 42a-b and 46a-b are
matched to the position of the golf ball 56 based on the estimated
distance traveled from the exposures 104. Next, the velocity of the
golf ball 56 is obtained from Vx, Vy and Vz using a linear
approximation. Next the golf ball speed is obtained by calculating
the magnitude of Vx, Vy and Vz.
[0091] The launch angle=sin.sup.-1 (Vz/golf ball speed),
[0092] and the spin angle=sin.sup.-1 (Vy/golf ball speed).
[0093] Next, the system 20 looks for the stripes 108a-b, as shown
in FIGS. 15 and 15A, on the golf ball 56 by using a random
transformation searching for the spot of greatest contrast. X, Y
and Z coordinates are used with the arc of stripe 108a and the arc
of stripe 108b to orient the arc on the golf ball. Then, the system
20 determines which arc is most normal using
(x.sup.2+y.sup.2).sup.1/2.
[0094] Next, the .THETA. angle of the golf ball 56 is measured by
taking the first vector and the second vector and using the
equation:
.THETA.=cos.sup.-1[(vector A1)(vector A2)]/([V.sub.1][V.sub.2])
where [V.sub.1] is the magnitude of V.sub.1 and [V.sub.2] is the
magnitude of V.sub.2.
[0095] As the golf ball 56 rotates from the position shown in FIG.
15 to the position shown in FIG. 15A, the angle .THETA.) is
determined from the position of vector A at both rotation
positions. This allows for the spin to be determined. The back spin
is calculated and applied to the first set of axis with a tilt axis
of zero. The resultant vectors are compared to those of the next
image and a theta is calculated for each of the vectors. This is
done for each tilt axis until the Theta between the rotated first
set of axis and the second set of axis is minimized.
[0096] The following is an example of how the system captures and
analyzes golf club information and golf ball information during and
after a golfer's swing. The golf club information includes golf
club head orientation, golf club head velocity, and golf club spin.
The golf club head orientation includes dynamic lie, loft and face
angle of the golf club head. The golf club head velocity includes
path of the golf club head, attack of the golf club head and
downrange information. The golf ball information includes golf ball
velocity, golf ball launch angle, golf ball side angle, golf ball
speed manipulation and golf ball orientation. The golf ball
orientation includes the true spin of the golf ball, and the tilt
axis of the golf ball which entails the back spin and the side spin
of the golf ball.
[0097] First the golf club 33 information is obtained by the system
20 with the assistance of an operator in inputting some preliminary
data. The size of the highly reflective points 106, separation of
the highly reflective points 106, and threshold setting are
inputted into the computer 22 by the operator. Next, as shown in
FIGS. 16 and 17, a bounding area 120 is set about the teed golf
ball 32 before the determining the threshold level on a grey scale
of 0 to 255 which is a measurement of the light intensity. An
appropriate setting of the threshold is 200 for the first plurality
of exposures 102. The operator inputs a mark which designates the
location of the teed ball 32. The bounding area 120 is determined
to be the area to the left of this mark in order to analyze the
first plurality of exposures 102. The system 20 then sets a
threshold level to the left of the teed golf ball 32 looking for
areas which are brighter then the threshold value. The system 20
then extracts the points from those greater than the threshold
value. The threshold level of the bounding area 120 is set, as
shown in FIGS. 18 and 19, which shows an absence of the golf ball
56 within the bounding area 120 since its brightness does not meet
the threshold value.
[0098] Next, the system 20 pairs the points 106a-c, verifying size,
separation, orientation and attack angle. Then, the system 20
captures a set of six points (three pairs) from a first find as
shown in FIGS. 20 and 21. Then, the system 20 searches above and
below the three pairs for a second find, as shown in FIG. 22 and
23. The repeated points 106 are eliminated and the results are
displayed from the find, as shown in FIGS. 24 and 25. The points of
the final pairs are processed by the computer 22 and displayed as
shown in FIG. 26.
[0099] Next the speed of the head of the golf club 33 is determined
by the system 20 using the equations discussed above.
[0100] Next the path angle and the attack angle of the golf club 33
is determined by the system 20. Using the methods previously
described, the attack angle is determined from the following
equation:
Attack angle=-atan(.DELTA.z/.DELTA.x)
[0101] Where .DELTA.z is the z value of the midpoint between 106a,
and 106b, minus the z value of the midpoint between 106a.sub.3 and
106b.sub.3. Where Ax is the x value of the midpoint between 106a,
and 106b, minus the x value of the midpoint between 106a.sub.3 and
106b.sub.3.
[0102] The path angle is determined from the following
equation:
path angle=-atan(.DELTA.y/.DELTA.x)
[0103] Where .DELTA.y is the y value of the midpoint between
106a.sub.1 and 106b.sub.2 minus the y value of the midpoint between
106a.sub.3 and 106b.sub.3. Where Ax is the x value of the midpoint
between 106a, and 106b, minus the x value of the midpoint between
106a.sub.3 and 106b.sub.3.
[0104] Next, the golf ball 56 data is determined b the system 20.
First, the thresholding of the image is established as shown in
FIG. 27, at a lower grey scale value, approximately 100 to 120, to
detect the golf ball 56. Next, well-known edge detection methods
are used to obtain the best golf ball 56 center and radius, as
shown in FIG. 28. Next, the stereo correlation of two dimensional
points on the golf ball 56 is performed by the system 20 as in FIG.
29, which illustrates the images of the first camera 40 and the
second camera 44.
[0105] Next, based on the partial image frame 100 shown in FIG. 30,
with the positioning information provided therein, the speed of the
golf ball 56, the launch angle of the golf ball 56, and the side
angle of the golf ball 56 is determined by the system 20. The speed
of the golf ball is determined by the following equation:
[0106] Golf ball
speed=[.DELTA.X.sup.2+.DELTA.Y.sup.2+.DELTA.Z.sup.2].sup.-
1/2/.DELTA.T. For the information provided in FIG. 30, the speed of
the golf
ball=[(-161.68+(-605.26)).sup.2+(-43.41+(-38.46)).sup.2+(-282.74+(-1-
93.85)).sup.2].sup.1/2/(13127-5115), which is equal to 126 MPH once
converted from millimeters over microseconds.
[0107] The launch angle of the golf ball 56 is determined by the
following equation:
[0108] Launch angle=sin.sup.-1(Vz/golf ball speed) where
Vz=.DELTA.Z/.DELTA.T.
[0109] For the information provided in FIG. 30,
Vz=[(-282.74+(-193.85)]/(1- 3127-5115)=11.3 MPH.
[0110] Then, the launch angle=sin.sup.-1(11.3/126.3)=11.3
degrees.
[0111] The side angle of the golf ball 56 is determined by the
following equation: Side angle =sin.sup.-1(Vy/golf ball speed)
where Vy =AY/AT. For the information provided in FIG. 30,
Vy=[(-43.41+(-38.46)]/(13127-5115)=1- .4 MPH. Then, the side
angle=sin.sup.-1 (1.4/126.3)=0.6 degrees.
[0112] The ball spin is calculated by determining the location of
the three striped on each of the acquired golf balls. Matching each
axis in the field of view and determine which of the axis is
orthogonal to the vertical plane. The spin is then calculated by:
.THETA.=acos((vectorA1 dot vector A2)/mag(v1)*mag(v2)) as discussed
above.
[0113] From the foregoing it is believed that those skilled in the
pertinent art will recognize the meritorious advancement of this
invention and will readily understand that while the present
invention has been described in association with a preferred
embodiment thereof, and other embodiments illustrated in the
accompanying drawings, numerous changes, modifications and
substitutions of equivalents may be made therein without departing
from the spirit and scope of this invention which is intended to be
unlimited by the foregoing except as may appear in the following
appended claims. Therefore, the embodiments of the invention in
which an exclusive property or privilege is claimed are defined in
the following appended claims.
* * * * *