Information
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Patent Grant
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6431990
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Patent Number
6,431,990
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Date Filed
Friday, January 19, 200123 years ago
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Date Issued
Tuesday, August 13, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
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CPC
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US Classifications
Field of Search
US
- 473 54
- 473 55
- 473 131
- 473 139
- 473 140
- 473 198
- 473 199
- 473 200
- 473 219
- 473 220
- 473 221
- 473 222
- 473 223
- 473 224
- 473 226
- 473 233
- 473 409
- 434 247
- 434 252
- 434 257
- 434 249
- 434 251
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International Classifications
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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).
Description
CROSS REFERENCES TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
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.
2. Description of the Related Art
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.
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.
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.
Yet another example is a family of patent to Gobush et al., U.S. Pat. No. 5,471,383 filed on Sep. 30, 1994; U.S. Pat. No. 5,501,463 filed on Feb. 24, 1994; U.S. Pat. No. 5,575,719 filed on Aug. 1, 1995; and U.S. Pat. No. 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.
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.
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
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.
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.
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.
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.
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.
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.
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
FIG. 1
is a perspective view of the monitoring system of the present invention.
FIG. 2
is a schematic isolated side view of the teed golf ball and the cameras of the system of the present invention.
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.
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.
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.
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.
FIG. 5A
is a graph of the time (x-axis) versus activation/deactivation for the exposure of FIG.
5
.
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.
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.
FIG. 6A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
6
.
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.
FIG. 7A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
7
.
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.
FIG. 8A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
8
.
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.
FIG. 9A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
9
.
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.
FIG. 10A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
10
.
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.
FIG. 11A
is a graph of the time (x-axis) versus activation/deactivation for the exposures of FIG.
11
.
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.
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.
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.
FIG. 15
is an isolated view of a golf ball striped for measurement using the present invention at a first exposure.
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 Θ.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
FIG. 26
is a chart of the processed final pairs giving the x, y and z coordinates.
FIG. 27
is an illustration of the thresholding of the exposures for the golf ball in flight.
FIG. 28
is an isolated view of the golf ball to illustrate determining the best ball center and radius.
FIG. 29
is a partial flow chart with images of golf balls for stereo correlating two dimensional points.
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
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.
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.
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 α
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 α
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.
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
62
a
and
62
b
, while the optical view of the second camera unit
28
is bound by lines
64
a
and
64
b
. The overlap area defined by curves
70
is the field of view of the system
20
.
The first camera unit
26
includes a first camera
40
and flash units
42
a
and
42
b
. The second camera unit
28
includes a second camera
44
and flash units
46
a
and
46
b
. A preferred camera is a charged coupled device (“CCD”) camera available from Wintriss Engineering of California under the product name OPSIS1300 camera.
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
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
.
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
.
FIG. 5
is a first exposure
102
a
only illustrating the three reflective points on the golf club
33
. The points
106
a-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
102
a
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
106
a-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.
As shown in
FIG. 6
, a second exposure
102
b
of the first plurality of exposures
102
is added to the first exposure
102
a
of the first plurality of exposures
102
. The second exposure
102
b
also only illustrates the three reflective points
106
a-c
of the golf club
33
. As shown in
FIG. 6A
, the exposure
102
b
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
102
a
and
102
b
is 795.9 milliseconds.
As shown in
FIG. 7
, a third exposure
102
c
of the first plurality of exposures
102
is added to the first exposure
102
a
and second exposure
102
b
of the first plurality of exposures
102
. The third exposure
102
c
also only illustrates the three reflective points
106
a-c
of the golf club
33
. As shown in
FIG. 7A
, the exposure
102
c
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
102
b
and
102
c
is 795.9 milliseconds. Thus, the time interval between the first plurality of exposures
102
is equal, and approximately 795.9 milliseconds.
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
.
FIG. 9
is the first exposure
104
a
of the second plurality of exposures
104
of the golf ball
56
in flight added to the other exposures. The first exposure
104
a
only illustrates the golf ball
56
. As shown in
FIG. 9A
, the exposure
104
a
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
106
a-c.
FIG. 10
is the second exposure
104
b
of the second plurality of exposures
104
of the golf ball
56
in flight, added to the other exposures. The second exposure
104
b
only illustrates the golf ball
56
. As shown in
FIG. 10A
, the exposure
104
b
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
104
a
and
104
b
is 978.7 milliseconds.
FIG. 11
is the third exposure
104
c
of the second plurality of exposures
104
of the golf ball
56
in flight, added to the other exposures. The third exposure
104
c
only illustrates the golf ball
56
. As shown in
FIG. 11A
, the exposure
104
c
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
104
b
and
104
c
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.
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.
For example, the low swing speed image frame
100
of
FIG. 12
has the first plurality of exposures
102
a-c
taken at 100 milliseconds from the triggering for exposure
102
a
, 1429.72 milliseconds from the triggering for exposure
102
b
, and 2759.44 milliseconds from the triggering for exposure
102
c
. The initial impact exposure
103
is taken at 5443.88 milliseconds from the triggering. The second plurality of exposures
104
a-d
are taken at 9793.93 milliseconds from the triggering for exposure
104
a
, 10775.15 milliseconds from the triggering for exposure
104
b
, 11756.37 milliseconds from the triggering for exposure
104
c
, and 12737.59 milliseconds from the triggering for exposure
104
d.
For comparison, the high swing speed image frame
100
of
FIG. 13
has the first plurality of exposures
102
a-c
taken at 100 milliseconds from the triggering for exposure
102
a
, 956.38 milliseconds from the triggering for exposure
102
b
, and 1091.62 milliseconds from the triggering for exposure
102
c
. The initial impact exposure
103
is taken at 2083.24 milliseconds from the triggering. The second plurality of exposures
104
a-d
are taken at 4091.48 milliseconds from the triggering for exposure
104
a
, 7335.83 milliseconds from the triggering for exposure
104
b
, 8799.44 milliseconds from the triggering for exposure
104
c
, and 9531.25 milliseconds from the triggering for exposure
104
d.
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.
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.
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
106
a-c
preferably positioned on the shaft, heel and toe of the golf club
33
. The highly reflective points
106
a-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
106
a-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.
As shown in
FIG. 14
, which is similar to
FIG. 7
, the first row of acquired highly reflective points
106
a
(on the shaft) is designated series one, the second row of acquired highly reflective points
106
b
(on the heel) is designated series two, and the third row of acquired highly reflective points
106
c
(on the toe) is designated series three. The first row is the acquired highly reflective points
106
a
from the shaft, the second row is the acquired highly reflective points
106
a
from the heel, and the third row is the acquired highly reflective points
106
a
from the toe. The following equation is used to acquire the positioning information:
d
=[(
Ptx−Pnx
)
2
+(
Pty−Ptny
)
2
. . . ]
½
where d is the distance, Ptx is the position in the x direction and Pty is the position in the y direction.
The system
20
may use a three point mode or a two point mode to generate further information. The two point mode uses V
toe
, V
heel
and V
clubtop
to calculate the head speed.
V
toe
=[(
Ptx
3
−Ptx
1
)
2
+(
Pty
3
−Pty
1
)
2
+(
Ptz
3
−Ptz
1
)
2
]
½
[1
/ΔT]
V
heel
=[(
Ptx
3
−Ptx
1
)
2
+(
Pty
3
−Pty
1
)
2
+(
Ptz
3
−Ptz
1
)
2
]
½
[1
/ΔT]
V
clubtop
=[V
toe
+V
heel
][½]
Vy
=[(
y
3heel
−y
1heel
)
2
+(
y
3toe
−Y
1toe
)
2
]
½
[1/(2
*ΔT
)]
Vz
[(
z
3heel
−z
1heel
)
2
+(
z
3toe
−z
1toe
)
2
]
½
[1/(2
*ΔT
)]
This information is then used to acquire the path angle and attack angle of the golf club
33
. The Path angle=sin
−1
(Vy/[V]) where [V] is the magnitude of V.
The attack angle=sin
−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.
The two point mode uses the shaft highly reflective point
106
a
or the toe highly reflective point
106
c
along with the heel highly reflective point
106
b
to calculate the head speed of the golf club, the path angle and the attack angle. Using the shaft highly reflective point
106
a
, the equations are:
V
heel
=[(
Ptx
3
−Ptx
1
)
2
+(
Pty
3
−Pty
1
)
2
+(
Ptz
3
−Ptz
1
)
2
]
½
[1
/ΔT]
V
shaft
=[(
Ptx
3
−Ptx
1
)
2
+(
Pty
3
−Pty
1
)
2
+(
Ptz
3
−Ptz
1
)
2
]
½
[1
/ΔT]
V
center
=1.02*(
V
shaft
+V
heel
)
Vy
=[(
y
3heel
−y
1heel
)
2
+(
y
3shaft
−y
1shaft
)
2
]
½
[1/(2
*ΔT
)]
Vz
=[(
z
3heel
−z
1heel
)
2
+(
z
3shaft
−z
1shaft
)
2
]
½
[1/(2
*ΔT
)]
The Path angle=sin
−1
(Vy/[V]) where [V] is the magnitude of V.
The attack angle=sin
−1
(Vz/[V]).
Using the toe highly reflective point
106
c
, the equations are:
V
toe
=[(
x
3
−x
1
)
2
+(
y
3
−y
1
)
2
+(
z
3
−z
1
)
2
]
½
[1
/ΔT]
V
heel
=[(
x
2
−x
1
)
2
+(
y
2
−y
1
)
2
+(
z
2
−z
1
)
2
]
½
[1
/ΔT]
V
clubtop
=[V
toe
+V
heel
][½]
The path angle=sin
−1
(Vy
clubtop
/[V
clubtop
]) where [V
clubtop
] is the magnitude of V
clubtop
.
The attack angle=sin
−1
(Vz
clubtop
/[V
clubtop
]) where [V
clubtop
] is the magnitude of V
clubtop
.
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
42
a-b
and
46
a-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.
The launch angle=sin
−1
(
Vz
/golf ball speed),
and the spin angle=sin
−1
(
Vy
/golf ball speed).
Next, the system
20
looks for the stripes
108
a-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
108
a
and the arc of stripe
108
b
to orient the arc on the golf ball. Then, the system
20
determines which arc is most normal using (x
2
+y
2
)
½
.
Next, the Θ angle of the golf ball
56
is measured by taking the first vector and the second vector and using the equation:
Θ=cos
−1
[(vector
A
1
) (vector
A
2
)]/([
V
1
][V
2
]) where [
V
1
] is the magnitude of
V
1
and [
V
2
] is the magnitude of
V
2
.
As the golf ball
56
rotates from the position shown in
FIG. 15
to the position shown in
FIG. 15A
, the angle Θ 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.
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.
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.
Next, the system
20
pairs the points
106
a-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
.
Next the speed of the head of the golf club
33
is determined by the system
20
using the equations discussed above.
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=−
a
tan(Δ
z/Δx
)
Where Δz is the z value of the midpoint between
106
a
1
and
106
b
1
minus the z value of the midpoint between
106
a
3
and
106
b
3
. Where Δx is the x value of the midpoint between
106
a
1
and
106
b
1
minus the x value of the midpoint between
106
a
3
and
106
b
3
.
The path angle is determined from the following equation:
path angle=−
a
tan(Δ
y/Δx
)
Where Δy is the y value of the midpoint between
106
a
1
and
106
b
1
minus the y value of the midpoint between
106
a
3
and
106
b
3
. Where Δx is the x value of the midpoint between
106
a
1
and
106
b
1
minus the x value of the midpoint between
106
a
3
and
106
b
3
.
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
.
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:
Golf ball speed=[Δ
X
2
+ΔY
2
+ΔZ
2
]
½
ΔT.
For the information provided in FIG.
30
,
the speed of the golf ball=[(−161.68+(−605.26))
2
+(−43.41+(−38.46))
2
+(−282.74+(−193.85))
2
]
½
/(13127−5115),
which is equal to 126 MPH once converted from millimeters over microseconds.
The launch angle of the golf ball
56
is determined by the following equation:
Launch angle=sin
−1
(
Vz
/golf ball speed) where
Vz=ΔZ/ΔT.
For the information provided in FIG.
30
,
Vz
=[(−282.74+(−193.85)]/(13127−5115)=11.3 MPH.
Then, the launch angle=sin
−1
(11.3/126.3)=11.3 degrees.
The side angle of the golf ball
56
is determined by the following equation:
Side angle=sin
−1
(
Vy
/golf ball speed) where
Vy=ΔY/ΔT.
For the information provided in FIG.
30
,
Vy
=[(−43.41+(−38.46)]/(13127−5115)=1.4 MPH.
Then, the side angle=sin
−1
(1.4/126.3)=0.6 degrees.
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:
Θ=
a
cos((vector
A
1
dot vector
A
2
)/mag(
v
1
)*mag(
v
2
)) as discussed above.
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.
Claims
- 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.
US Referenced Citations (62)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO 0043936 |
Jul 2000 |
WO |