U.S. patent application number 10/943814 was filed with the patent office on 2005-09-15 for method and apparatus for sport swing analysis system.
Invention is credited to Lawson, Thomas E., Otten, Leslie B..
Application Number | 20050202889 10/943814 |
Document ID | / |
Family ID | 25493172 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050202889 |
Kind Code |
A1 |
Otten, Leslie B. ; et
al. |
September 15, 2005 |
Method and apparatus for sport swing analysis system
Abstract
A sports swing analysis system analyzes characteristics of a
golf club swing and operates in putting mode.
Inventors: |
Otten, Leslie B.;
(Greenwood, ME) ; Lawson, Thomas E.; (Malvern,
PA) |
Correspondence
Address: |
James W. Wiegand
Law Office of James Wiegand
Suite 700
60 State Street
Boston
MA
02109
US
|
Family ID: |
25493172 |
Appl. No.: |
10/943814 |
Filed: |
September 15, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10943814 |
Sep 15, 2004 |
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09952714 |
Sep 14, 2001 |
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6821211 |
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Current U.S.
Class: |
473/151 |
Current CPC
Class: |
A63B 69/3614 20130101;
A63B 2220/805 20130101 |
Class at
Publication: |
473/151 |
International
Class: |
A63B 067/02 |
Claims
What is claimed is:
1. A golf swing analyzer comprising: a radiation source configured
to emit electromagnetic radiation toward a location in the path of
a swung golf club, a radiation receiver configured to receive
electromagnetic radiation reflected from the swung golf club; a
controller configured to generate at least one signal for each
transition in light level reflected from the golf club head; and
the controller configured to analyze parameters of a golf club
swung at a speed that is lower than a valid swing speed.
2. The putting analyzer of claim 1 wherein the controller is
configured to respond to user input by entering a putting mode in
which the controller is responsive to signals generated by light
level transitions.
3. The putting analyzer of claim 2 wherein the controller is
configured to operate in the putting mode until user input
terminates the putting mode.
4. The putting analyzer of claim 3 wherein the controller is
configured to operate in the putting mode until a predetermined
period transpires during which no light level transition signals
are generated.
5. The swing analyzer of claim 2 where the controller is configured
to recognize swing speeds greater than or equal to ten miles per
hour as valid swing speeds.
6. A golf swing analyzer comprising: a radiation source configured
to emit electromagnetic radiation toward a location in the path of
a swung golf club, a radiation receiver configured to receive
electromagnetic radiation reflected from the swung golf club; a
controller configured to generate at least one signal for each
transition in light level reflected from the golf club head; and
the controller configured to analyze parameters of a golf club in
two modes, one mode corresponding to a swing that is greater than
or equal to a threshold speed and a second, putting mode, that is
less than the threshold speed.
6. The golf swing analyzer of claim 6 wherein the controller is
configured to enter the putting mode in response to user input.
7. The golf swing analyzer of claim 6 wherein the controller is
configured to enter the putting analysis mode in response to a
pattern of light level transition signals.
8. A golf swing analysis method comprising the steps of (A) a
radiation source emitting electromagnetic radiation toward a
location in the path of a swung golf club, (B) a radiation receiver
receiving electromagnetic radiation reflected from the swung golf
club; (C) a controller generating at least one signal for each
transition in light level reflected from the golf club head; and
(D) the controller analyzing parameters of a golf club swung at a
speed that is lower than a valid swing speed.
9. The method of claim 8 further comprising the step of: (E) the
controller responding to user input by entering a putting mode in
which the controller is responsive to signals generated by light
level transitions.
10. The method of claim 9 further comprising the step of: (F) the
controller operating in the putting mode until user input
terminates the putting mode.
11. The method of claim 10 further comprising the step of: (G) the
controller operating in the putting mode until a predetermined
period transpires during which no light level transition signals
are generated.
12. The method of claim 9 further comprising the step of: (H) the
controller recognizing swing speeds greater than or equal to ten
miles per hour as valid swing speeds.
13. A golf swing analysis method comprising the steps of: (A) a
radiation source emitting electromagnetic radiation toward a
location in the path of a swung golf club, (B) a radiation receiver
receiving electromagnetic radiation reflected from the swung golf
club; (C) a controller generating at least one signal for each
transition in light level reflected from the golf club head; and
(D) the controller analyzing parameters of a golf club in two
modes, one mode corresponding to a swing that is greater than or
equal to a threshold speed and a second, putting mode, that is less
than the threshold speed.
14. The golf swing analysis method of claim 13 further comprising
the step of: (E) the controller entering the putting mode in
response to user input.
15. The golf swing analysis method of claim 13 further comprising
the step of: the controller entering the putting analysis mode in
response to a pattern of light level transition signals.
Description
[0001] This application is a continuation of United States patent
application having Ser. No. 09/952,714, entitled, "SPORT SWING
ANALYSIS SYSETM," which is hereby incorporated by reference in its
entirety. The present application has the same inventors as, is
assigned to the same entity as, and claims benefit of the same
filing date, Sep. 14, 2001, as this application. Applications
having the same inventors, the same assignee, and docket numbers:
GT1CONTA, GT1CONTB, GT1CONTC, GT1CONTD, GT1CONTE, GT1CONTF,
GT1CONTG, GT1CONTH, GT1CONTI, and GT1CONTJ are being filed on the
same day herewith and each incorporates the other by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to systems and methods to aid
in analyzing the swing associated with athletic activities. More
particularly, the present invention relates to a system and method
for detecting and analyzing the path and orientation of an sports
implement, such as a golf club, as it is swung. Although the
present invention is well suited to the analysis of a golf club's
swing, its application is not limited thereto.
BACKGROUND OF THE INVENTION
[0003] Practice makes perfect. However hackneyed that bromide may
be, it offers an element of truth. That is, the skill-level of an
individual, particularly in those tasks that involve muscle-memory,
such as athletic or musical-performance activities, is directly
related to the number of quality hours spent engaged in those
pursuits. Pete Maravich almost always had his hands on a
basketball, Jimi Hendrix rarely set his guitar down; even those
with great natural ability developed their talents through many,
many hours of practice. The implication of the term "quality hours"
is that the time must be spent in a manner that provides feedback
to allow the practitioner to modify his execution in order to
improve his performance. A "sour note" in a blues riff, a
concussion incurred while attempting a double back flip off a high
board, or a hook into the rough off a golf tee are all forms of
feedback that provide a learning opportunity to an aspiring
competitor/performer.
[0004] There are a number of sports activities that involve
extraordinarily complex swinging movements. The fact that no major
league player has hit 0.400 since Ted Williams did so in his 1941
season is a testament to the extreme difficulty of effectively
swinging a baseball bat. A sixty percent failure rate would be
disastrous in nearly any other endeavor, but, in baseball, it's the
apex of performance. Similarly, the many mechanical degrees of
freedom associated with a golf swing conspire to provide the
average duffer with many opportunities for failure and the
mechanics of swinging a tennis racquet are critical to success in
that sport. Ice hockey, field hockey, and lacrosse are among the
other sport activities that rely upon the skillful swing of an
implement (that is, a bat, a club, a racquet, etc.). Although
professionals are available to help athletes improve their swings
(e.g., hitting coaches for baseball players and golf and tennis
professionals), costs associated with such lessons are beyond the
means of the vast majority of players. Scheduling the time for and
traveling to lessons adds another layer of inconvenience to this
approach for improving your golf game. Additionally, athletic
activities involving the use of an implement moving at a high rate
of speed, it can be difficult to accurately assess any flaws in the
mechanics of an individual's swing.
[0005] Devices and systems are available for sport participants to
make critical evaluations of the techniques and mechanics
associated with their sport of interest. In the sport of golf there
have been a number of advances in golf club swing analysis. For
example, U.S. Pat. No. 5,718,639 issued to Bouton, U.S. Pat. No.
5,474,298 issued to Lindsay, and U.S. Pat. No. 6,227,984 issued to
Blankenship, disclose various approaches to sensing and analyzing
golf swings. Notwithstanding the abundance of swing analysis
systems, the development of accurate, inexpensive swing sensing and
analysis systems remains elusive.
[0006] An automated system that analyzes a sport swing and provides
feedback to a player as a convenient, accurate, low-cost
alternative to the engagement of coaches and/or professionals would
be highly desirable.
SUMMARY
[0007] A sport swing analysis system and method in accordance with
the principles of the present invention senses electromagnetic
energy reflected from a sports implement. The reflected energy may
be of any wavelength or band of wavelengths. Although the
wavelength of the energy may fall outside the range referred to as
the visual spectrum, the energy will be referred to hereinafter as
"light." For the purpose of illustration, examples of operation
using infrared light will be employed.
[0008] A system and method in accordance with the principles of the
present invention emits light then detects light reflected from a
sports implement, such as a golf club, baseball bat, or tennis
racquet, for example. As the sports implement passes by one or more
of photo-emitters (emitters) the implement reflects a portion of
the light striking it from the emitters. One or more
photo-detectors (detectors) detect light reflected from the
implement and the amplitude of light reflected into one or more of
the detectors will vary with the passing of the implement.
[0009] In accordance with the principles of the present invention,
the system may employ pattern recognition methods and apparatus,
including, but not limited to, edge detection techniques, to
distinguish the light reflected from the implement and received at
the detector(s) from background light and light from other sources
that is received at the detector(s). Light from outside sources,
also referred to herein as "artifact," is a potential source of
error and, once identified, is ignored by the system. In an
illustrative embodiment, the edge-detection process includes the
step of differentiating a swung sports implement's reflection
profile to determine one or more points of inflection in the
profile. The one or more points of inflection correspond to
relatively sharp transitions in the amplitude of reflected light,
and correspond to one or more identifiable features on the swung
implement. Each identifiable feature may, for example, be a
transition between materials having relatively high light
absorption and relatively high light reflectivity. In an
illustrative embodiment, the system stores information related to
each such light level transition that meets a threshold criteria.
Such information may include the time at which the transition
occurred (that is, a time stamp) and a "tag" that identifies the
detector that detected the light-level transition.
[0010] In an illustrative example, the identifiable features may be
the leading and trailing edges of a reflective strip coupled to the
swung implement. The reflective strip may be coupled to the
implement using any attachment means, including, but not limited
to, adhesives, hook and loop, tying, or strapping, for example.
Alternatively, the reflective material may be integral with the
swung implement, with one or more strips of reflective material
embedded within the head of a golf club, within the body of a
baseball bat, or within the head of a tennis racquet, for example.
The reflective strip may, additionally, be flanked by one or more
regions of highly light-absorptive material in order to establish a
high-contrast reflectivity region: that is, a region in which the
material surfaces present an abrupt shift from highly
light-absorptive to highly light-reflective. Such a high-contrast
reflectivity region enhances the system's ability to detect
reflection transition events, thereby allowing the system to more
precisely determine the exact time and location of transition
events. For example, in an illustrative embodiment, a highly
absorptive material, such as black electrical tape, is applied to
the bottom surface of a golf club's head, then a strip of
retroreflective material, is attached, via adhesive backing, to the
absorptive material (that is, the black tape), with some of the
absorptive material left uncovered. The combination of absorptive
material and overlaid reflective material yields high-contrast
reflectivity regions at the leading and trailing edges of the
strip.
[0011] In another aspect of a system in accordance with the
principles of the present invention, the retroreflective strip is
of a known width and is aligned with leading and trailing edges
parallel to the face of the club. An alignment tool may be employed
to ensure that the strip is properly aligned with the face of the
club. Knowing the width of the reflective strip allows the system
to determine the speed of the associated swung implement by
dividing the width of the strip by the time between reflectivity
transitions associated with the leading and trailing edges of the
reflective strip.
[0012] Triangulation techniques may be employed by a system in
accordance with the principles of the present invention to
determine the distance between the implement and the system's light
detectors. In an illustrative golf club swing analysis embodiment,
such a distance measurement may be used to provide an indication of
the height of a swung club head above a surface holding the golf
ball. Such a golf club swing analysis embodiment may include one or
more arrays of detectors and emitters) embedded in a housing that
provides support for a golf ball on its upper surface. The emitters
and detectors are coupled to a controller that controls the output
of the emitters and samples the input to the detectors. The
controller may also perform signal conditioning, the timestamping,
amplitude profile creation, and edge detection processes discussed
briefly above, or, alternatively, may offload some, or all, of
these tasks to an associated computer. The tasks associated with a
swing analysis system in accordance with the principles of the
present invention may be divided between the controller and a
computer in a number of ways. In an illustrative embodiment, the
amplitude profile stored includes the identification of the
detector that experienced the light transition, the direction of
the transition (that is, going from dark to light, or going from
light to dark), and the time of the transition. However those tasks
are divided, the system may be used to determine and display swing
path angle, club head speed, club head angle, club head lateral
alignment with respect to a ball support, club head loft angle, and
club head height. Additionally, the system may be employed to
calculate and display an "effective club head speed," which takes
into account the raw speed of the club head and discounts that
speed according to swing path angle, club head lateral alignment,
and club head angle. Sensor arrays (that is, arrays of emitters and
detectors) are positioned within and supported by a sensor housing
in a manner that permits the sensors to detect and analyze the
passage of a swung club before, after, and at the point of impact
with a ball.
[0013] A swing analysis system in accordance with the principles of
the present invention may analyze slower motioned swings, such as
putting strokes in a golf swing analysis embodiment and may
incorporate both "regular" swing analysis (that is, the analysis of
swings other than putting strokes) and putting swing analysis into
one or more practice modes and into one or more game modes.
[0014] The system may include a user interface the provides a
variety of textual and graphical information related to swing
analysis and may include views of a struck ball's trajectory
including, "still", "follow the ball", and "spin" views. In the
"still" view, the user observes the ball trajectory from a
stationary viewpoint corresponding to the place where he was
standing when he hit the ball. In the "follow the ball" view, the
user's viewpoint follows the ball, as thought tethered to the ball.
In the "spin" view, the viewpoint follows the ball and then spins
to a side view that travels along with the ball.
[0015] An applicator that properly aligns reflective material on
the implement that is to be swung for analysis is also contemplated
within the scope of the invention, as is a mat that is configured
to receive a sensor housing and to support a user at approximately
the same level as the top of the sensor housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The above and further features, aspects, and advantages of
the invention will be apparent to those skilled in the art from the
following detailed description, taken together with the
accompanying drawings in which:
[0017] FIG. 1a is a conceptual block diagram of a sports swing
analysis system in accordance with the principles of the present
invention and FIGS. 1b, 1c, and 1d depict a baseball bat, a tennis
racquet, and a golf club coupled to retroreflective materials in
accordance with the principles of the present invention;
[0018] FIG. 2 is a perspective view of a golf swing analyzer system
in accordance with the principles of the present invention;
[0019] FIGS. 3a through 3h illustrate the application of
retroreflective materials to a golf club head in accordance with
the principles of the present invention;
[0020] FIG. 4 is a top plan view of a golf swing analyzer sensor
housing in accordance with the principles of the present
invention;
[0021] FIGS. 5a through 5b illustrate in greater detail the
operation of a golf swing analyzer in combination with
retroreflective materials in accordance with the principles of the
present invention;
[0022] FIG. 6 is a block diagram of a sensor system in accordance
with the principles of the present invention;
[0023] FIG. 7 is a block diagram of a computer such as may be used
in implementing a sports swing analysis system in accordance with
the principles of the present invention;
[0024] FIG. 8 is a flow chart of the process of sports swing
analysis in accordance with the principles of the present
invention;
[0025] FIG. 9 is a screen shot of a sports swing analysis system in
accordance with the principles of the present invention in which
display components related to a golf swing are illustrated;
[0026] FIG. 10 is a screen shot of a sports swing analysis system
in accordance with the principles of the present invention in which
display components related to a golf putting swing are
illustrated;
[0027] FIG. 11 is a screen shot of a sports swing analysis system
in accordance with the principles of the present invention in which
display components related to a golf course layout are illustrated;
and
[0028] FIGS. 12a and 12b are, respectively, perspective and end
views of a golf mat such as may be employed by a sports swing
analysis system in accordance with the principles of the present
invention.
DETAILED DESCRIPTION
[0029] A sports swing analysis system in accordance with the
principles of the present invention may be configured and employed
to analyze the characteristics of a swung sports implement.
Although the implement could be any of a number of sports
implements that are swung during the course of a sports activity,
such as a baseball bat, a tennis racquet, a hockey stick, or a golf
club, the following description will concentrate, for the sake of
brevity and clarity of exposition, on the detection and analysis of
a golf swing, in the details.
[0030] The conceptual block diagram of FIG. 1a outlines three
functional building blocks of a sports swing analysis system 100 in
accordance with the principles of the present invention. The
detection systems 102 interface with signal generation and
processing functions 104 that, in turn, interface with analysis,
control, and user interface functions 106. The functions
represented in the blocks 102, 104, and 106 may be distributed in a
number of ways; with the functions dispersed in a plurality of
packages or with all the functions located within a single package.
As will be described in greater detail in the discussions related
to subsequent Figures, in an illustrative embodiment of a golf
swing analysis system, the majority of the detection system 102 and
signal generation and processing 104 functions are located within a
sensor housing that is linked with a general purpose computer upon
which have been coded the analysis, control, and user interface
functions 106.
[0031] The detection system functions 102, as described in greater
detail in the discussion related to the following Figures, include
the placement and orientation of electromagnetic emitters and
detectors and the use of retroreflective materials to optimize the
operation of the emitters and detectors. Although the
electromagnetic energy employed by the photoemitters (emitters) and
photodetectors (detectors) may be of any wavelength or band of
wavelengths, and the wavelength(s) of the energy may fall outside
the range referred to as the visual spectrum, the energy will be
referred to hereinafter as "light." For the ease and clarity of
illustration, examples of operation using infrared light will be
employed.
[0032] A system and method in accordance with the principles of the
present invention emits light then detects light reflected from a
sports implement, such as a golf club, baseball bat, or tennis
racquet, for example. As the sports implement passes by one or more
of photo-emitters (emitters) the implement reflects a portion of
the light striking it from the emitters. One or more
photo-detectors (detectors) detect light reflected from the
implement and the amplitude of light reflected into one or more of
the detectors will vary with the passing of the implement.
[0033] In accordance with the principles of the present invention,
the system may employ pattern recognition methods and apparatus,
including, but not limited to, edge detection techniques, to
distinguish the light reflected from the implement and received at
the detector(s) from background light and light from other sources
that is received at the detector(s). Light from outside sources,
also referred to herein as "artifact," is a potential source of
error and, once identified, is ignored by the system. In an
illustrative embodiment, the edge-detection process includes the
step of differentiating a swung sports implement's reflection
profile to determine one or more points of inflection in the
profile. The one or more points of inflection correspond to
relatively sharp transitions in the amplitude of reflected light,
and correspond to one or more identifiable features on the swung
implement. Each identifiable feature may, for example, be a
transition between materials having relatively high light
absorption and relatively high light reflectivity. In an
illustrative embodiment, the system stores information related to
each such light level transition that meets a threshold criteria.
Such information may include the time at which the transition
occurred (that is, a time stamp) and a "tag" that identifies the
detector that detected the light-level transition.
[0034] In an illustrative example, the identifiable features may be
the leading and trailing edges of a reflective strip coupled to the
swung implement. The reflective strip may be coupled to the
implement using any attachment means, including, but not limited
to, adhesives, hook and loop, tying, or strapping, for example.
Alternatively, the reflective material may be integral with the
swung implement, with one or more strips of reflective material
embedded within the head of a golf club, within the body of a
baseball bat, or within the head of a tennis racquet, for example.
The reflective strip may, additionally, be flanked by one or more
regions of highly light-absorptive material in order to establish a
high-contrast reflectivity region: that is, a region in which the
material surfaces present an abrupt shift from highly
light-absorptive to highly light-reflective. Such a high-contrast
reflectivity region enhances the system's ability to detect
reflection transition events, thereby allowing the system to more
precisely determine the exact time and location of transition
events.
[0035] For example, in an illustrative embodiment, a highly
absorptive material, such as black electrical tape, is applied to
the bottom surface of a golf club's head, then a strip of
retroreflective material, is attached, via adhesive backing, to the
absorptive material (that is, the black tape), with some of the
absorptive material left uncovered. The combination of absorptive
material and overlaid reflective material yields high-contrast
reflectivity regions at the leading and trailing edges of the
strip. FIG. 1b illustrates a baseball bat 108 having a plurality of
reflective strips 110 attached to the tip of the bat 108 over
highly light-absorbent material 112. FIG. 1c illustrates a tennis
racquet 114 having a reflective strip 116 attached to the racket
over a highly light-absorbent material 118. FIG. 1d illustrates a
golf club 210 having a reflective strip attached to the club over a
highly light-absorbent material 213. The placement of the
reflective strip and light absorbent material for all the
implements may vary with application.
[0036] The signal generation and processing functions 104, as
described in greater detail in the discussion related to the
following Figures, include the use of pattern detection techniques
and the timed activation of the emitters. The analysis, control,
and user interface functions 106, described in greater detail in
the discussion related to the following Figures, include the
analysis of a swung implement, display of a simulated result of the
swing, and audio and/or graphical feedback related to the analysis
of the swing.
[0037] An illustrative embodiment of a golf swing analysis system
200 in accordance with the principles of the present invention is
shown in the perspective view of FIG. 2. The system 200 include a
sensor housing 202 or equivalent structure for containing therein a
plurality emitters and detectors. As will be described in greater
detail in the discussion related to the following Figures, the
emitters and detectors are arranged into six groups, or arrays,
identified in the Figures by reference numerals 204a, 204b, 204c,
204d, 204e, and 204f. The system 200 further includes signal
generation and processing components 206 contained, in this
illustrative embodiment, within the housing 202. As described in
greater detail in the discussion related to the following Figures,
the signal generation and processing components are coupled to the
emitters and detectors (204a-204f) and to a general purpose
computer 208.
[0038] A golf club 210 having retroreflective material 212 coupled
to it is swung by a user over the housing 202 in order to capture
data for analysis of the user's golf swing, and for providing
various forms of feedback to the user by the system 200. A mat 215
may be employed to provide a level, resilient, grass-like surface
upon which a user may stand. The mat 215 simulates the look and
feel of a golf course surface and, with a thickness approximately
the same as the thickness of the housing 202, positions a user
level with the upper surface 202a of the housing 202. The
illustrative system 200 also includes a net 214 which may be
positioned to capture golf balls hit by a user.
[0039] Retroreflective material, such as used in this illustrative
embodiment, is familiar to most people through its use in traffic
signs. The material provides the unique property of returning light
to a light source, rather than, as with conventional reflective
material, reflecting light according to the familiar, "angle of
incidence equals the angle of reflection," rule. Retroreflective
materials are typically one of two types: enclosed-lens, glass bead
sheeting, or microprismatic, "cube-corner," reflective material.
"Glass bead" sheeting features a complex construction of many
laminated layers. Thousands of microscopic glass beads are embedded
per square inch in these layers. Sandwiched between the adhesive
and bead layers, a metalization layer is closely molded to the
contoured backside of the beads, and acts as a reflector. Light
passes through the film's top layers and strikes this layer.
Bouncing off the metalization layer, light returns through the
beads back through to the light source. Microprismatic
retroreflective material uses an embossed geometric pattern on the
sheeting's interior surface to refract the light beam. By bouncing
the light off different planes of the pattern, the light is
redirected back to its origin. Various retroreflective film types
are available from manufacturers, such as 3M corporation, Saint
Paul, Minn.
[0040] The illustrative sensor housing 202 may be fabricated of a
resilient material, with the emitters and detectors (204a-204f)
embedded therein. In this illustrative embodiment, the emitters and
detectors are reflective type sensors wherein the detectors produce
a signal proportional to the amplitude of light they detect of the
wavelength emitted by the emitters. Typically, background radiation
will contribute to a signal at one or more of the detectors, but,
as described in greater detail in the discussion related to the
following Figures, the system 200 employs signal processing
techniques to eliminate the effects of such "artifact." This
illustrative embodiment employs QED123 and QSD123 emitters and
detectors, respectively, available from Fairchild Semiconductors.
The housing 202 is primarily composed of opaque material, with
ports formed in the upper surface 202a of the housing 202 at the
locations of the sensors 204a-204f. In this illustrative
embodiment, each of the sensors may be thought of as an
emitter/detector pair. Emitters within a group of sensors will be
referenced by the addition of an "e" to the respective sensor's
reference number, and detectors will be referenced by the addition
of a "d" to the respective sensor's reference number. For example,
emitters within the 204a sensor group will be associated with
reference numeral 204ae and, similarly, detectors within the 204a
sensor group will be associated with the reference numeral 204ad.
The ports may be open or covered by a resilient material, such as
Plexiglas, that does not substantially absorb light at the
wavelength employed by the sensors. In use, the housing 202 is
positioned such that when a golf club 210 is swung, the head of the
golf club 210 travels along a swing path 216 that passes over the
housing upper surface 202a. Specifically, the swing path 216 passes
over the housing back edge 202b, one or more of the sensors
(204a-204f), and then the housing front edge 202c. A ball support
205 will directly support a golf ball substantially at the level of
the housing upper surface 202a, to simulate the positioning of a
ball while putting or, in general, during any shot other than a tee
shot. Additionally, the ball support 205 is configured to accept a
golf tee and to thereby permit a golfer to take a tee shot.
[0041] In this illustrative embodiment, the emitters and detectors
of sensors 204a-204f respectively emit and accept relatively narrow
beams of infrared light. As described in greater detail in the
discussion related to the following Figures, the properties of the
reflective material 212 coupled to the head of the club 210 permit
the use of relatively narrow beams, which, in turn, provides
greater accuracy in detecting the presence or absence of the head
of a club 210 above the housing 202. In the illustrative
embodiment, the emitted light forms a beam with a spread of
approximately +/-11 degrees. The detectors are sensitive over a
comparably narrow range. Such as narrow beam allows the system to
distinguish smaller features over a greater distance than otherwise
would be the case. Consequently, the accuracy and resolution of the
system is increased concomitantly. With a conventional reflective
surface, the reflected energy would only activate the detectors if
the reflecting surface were substantially perpendicular to the
central beam of the incident light energy. Additionally, a change
in orientation relative to horizontal would appear as a horizontal
shift in position if a conventional reflective surface were
employed. In this illustrative embodiment, the reflective material
212 is a retroreflective tape that is applied to the bottom of the
head of the club 210. The process of applying the retroreflective
tape, along with a material 213 that is highly absorbent in the
wavelength or band of wavelengths used by the sensors 204a-204f, is
described in greater detail in the discussion related to FIGS. 3a
through 3j.
[0042] In operation, light transmitted by an emitter only returns
to a nearby, associated, detector when it is reflected by an
object, such as the retroreflective tape 212. As a club 210 is
swung along the swing path 216, light from one or more of the
emitters 204ae-204fe is reflected back to one or more of the
detectors 204ad-204fd by the reflective strip. Additionally, light
from the emitters 204ae-204fe is substantially absorbed before and
after passage of the reflective strip 212 by the absorbent material
213 which, in this illustrative example, substantially surrounds
the reflective strip 212. The contrast between high levels of
absorption and high levels of reflectivity provides for a sharp
transition in reflected light amplitude that a system in accordance
with the principles of the present invention may use to clearly
distinguish the passage of a club head from fluctuations in light
amplitude not due to the passage of a club head and, therefore, not
relevant to a sports swing analysis system. Not only does the sharp
contrast provided by the combination of absorbent and reflective
materials distinguish such background fluctuations from light
amplitude transitions of interest, it also allows the system 200 to
determine with some precision the exact time at which the edge of
the retroreflective material passes over a sensor and, therefore,
permits the system to more accurately determine the values of swing
parameters of interest, such as: swing path angle, club head speed,
club head angle, club head lateral alignment with respect to a ball
support, club head loft angle, and club head height.
[0043] The array of sensors 204a operate as triggers. That is,
power is constantly applied to the emitters and detectors so that
the sensors may detect the passage of a club head at any time. When
a trigger event is detected by sensors in the trigger row 204a, the
remaining sensors, in particular the emitters of the remaining
sensors, are turned on at full power for a period of time that is
sufficient to capture swing data. Contact row sensors 204d are
positioned in close enough proximity to a ball support 205 to
obtain club head data approximately at the time of the club's
impact with a ball. That is, the trailing edge of a properly placed
reflective strip will be detected substantially coincident with the
striking of the ball. Sensor arrays 204c and 204e are used to
evaluate club head toe and club head heel height before and after
the point of impact, which provides further information on how the
ball is struck relative to the sweet spot of the club head face.
Club head toe and heel height are determined using a technique that
is a variation on standard triangulation for distance
determination. In an illustrative embodiment, the sensors are
angled approximately 30 degrees with respect to a line
perpendicular to the upper surface of the housing 202a. However, it
will be understood that the sensors could be oriented at any
reasonable angle, for example, from 15 degrees to 75 degrees. Note
that, without the retroreflective surface, the angled beams would
not activate their respective detectors. Since each of the sensors
arrays 204c and 204e include two parallel rows (204cl and 204cr,
and 204el and 204er, respectively) effectively situated an equal
distance on either side of the tee, for a right handed golfer
swinging in the direction indicated by the path 216, the height of
the toe of the club is measured by sensor rows 204cr and 204er, and
the height of the heel of the club is measured by sensor rows 204cl
and 204el. This configuration enables the club head toe and heel
heights to be measured independently, which, in turn, enables the
system to provide a more accurate depiction of the swing, as is
described below. The operation of entrance row sensors 204b, exit
row sensors 204f and angled sensors 204c and 204e will be described
in greater detail below.
[0044] The ball support 205 may directly support a ball, for
example, when a golfer is operating the system in a putting mode,
or, with the insertion of a tee into the hole 207 within the ball
support by a golfer, the ball support 205 may support a tee which,
in turn, supports the ball. The output of the entrance row 204b and
exit row 204f sensors is used to determine the club's swing path
angle and the club head's lateral alignment with the ball. The
system employs a combination of parameter values, including: swing
path angle, lateral alignment, and face angle, to indicate whether
the ball has been struck on the center of the club head face (that
is, the sweet spot) or if the ball has been struck on the heel or
toe of the club head.
[0045] In accordance with the principles of the present invention,
a distance measurement device 211 may be employed to determine the
launch angle of a golf ball after a user strikes the ball. The
distance measurement device 211 may be based on any of a variety of
known technologies, such as RADAR or LIDAR, for example. In
operation, the distance measurement device is located a known
distance D4 from the ball support 205. Given the known distance D4,
the distance measurement obtained by the device 211 may be used by
the system to determine a golf ball's launch angle (that is, the
vertical angle of the ball as it leaves the ball support). In a
relatively simple embodiment, one or more of the devices 211 are
positioned down range of the ball support forming a line
perpendicular to the intended flight path of the ball at the
distance D4 from the ball support. As a struck ball passes over one
of the distance measurement devices 211, the device measures the
vertical distance to the ball H (that is, the ball's height) and
reports this information to a controller 600 (see FIG. 6). Given
the ball's height and the distance D4 to the ball support, the
controller or computer can determine the launch angle as the
arctangent of H/D4. This approach assumes that the height
measurement is obtained as the ball passes directly over the device
211 and, therefore, the angle between the line from the device 211
to the ball and the line from the ball support 205 to the device
211 is a right angle.
[0046] Other configurations are contemplated within the scope of
the invention. For example, in another illustrative embodiment, the
device 21 is a RADAR device that employs phased-array techniques to
steer a radar beam in order to determine the distance to a struck
ball from the device. Phased arrays and RADAR beam steering is
known in the art and compact, steerable, inexpensive RADAR systems
are known. A compact, inexpensive, steerable, RADAR is disclosed,
for example in, "A Fully Integrated 24-Ghz 8-path Phased Array
Receiver in Silicon", Hossein Hashemi, Xiang Guan, and Ali
Hamjimiri, International Solid State Circuits Conference, 2004,
which is hereby incorporated by reference in its entirety. A system
in accordance with the principles of the present invention may
employ a steerable RADAR to obtain a variety of measurements,
including the height and distance to a ball. Such measurements may
be made one or more times. Because such a RADAR device may be used
to determine both the distance and direction to a struck ball, the
device may be located anywhere within a range of interest (that is,
close enough to a projected ball flight path to obtain
measurements), and wouldn't need to be positioned down range from
the ball support 205. In order to transform angle and distance
measurements from the device's coordinate system to that of the
ball support and to thereby derive such measurements as ball launch
angle, the RADAR device's position relative to that of the ball
support must be determined. In order to simplify the coordinate
transformation, a RADAR device may be positioned a predetermined
distance D4 down range from the ball support, along a center line
that travels through the center of the ball support 205 in the
direction of the expected ball flight path. Readings obtained when
the ball is directly overhead provide a direct measure of a ball's
height and the ball's launch angle is given, as described above, by
the arctangent of H/D4. Vector decomposition may be used to
determine the height and directional angle (the angle, for example,
to the left or the right of the center line) of a ball by
transforming the height and angle of a ball in the receiver's
coordinate system to the height and angle of the ball in the ball
support's coordinate system. In accordance with the principles of
the present invention a steerable RADAR device 211 may also be
employed to make club head measurements, such as club head height,
speed, path, etc.
[0047] In another aspect of a system in accordance with the
principles of the present invention, the retroreflective strip is
of a known width and is aligned with leading and trailing edges
parallel to the face of the club. Additionally, an alignment tool
may be employed to ensure that the strip is properly aligned with
the face of the club. Knowing the width of the reflective strip
allows the system to determine the speed of the associated swung
implement by dividing the width of the strip by the time between
reflectivity transition events associated with the leading and
trailing edges of the reflective strip. Triangulation techniques
may be employed by a system in accordance with the principles of
the present invention to determine the distance between the
implement and the system's light detectors. In an illustrative golf
club swing analysis embodiment, such a distance measurement may be
used to provide an indication of the height of a swung club head
above a surface holding the golf ball.
[0048] FIGS. 3a through 3f provide illustrative examples of
light-absorbent and light-reflective material such as may be used
in accordance with the principles of the present invention and
their application to the head of a golf club, such as golf club
210. FIG. 3a is a bottom plan view of a golf club head 300 having
fore (or face) 302, aft 304, and bottom 306 surfaces. The face 302
strikes the ball, ideally, in a manner that provides preferred
characteristics, such as height, distance, direction, and other
characteristics discussed in greater detail in the discussion
related to the following Figures. In order to properly measure
parameters such as club head speed, loft, club face angle and club
path angle, the systems sensors 204a-204f must detect the actual
orientation of the club head as it is swung along the path 216.
Because the reflectivity of a club head varies, because of a club
head's curvature, and because these and other club head
characteristics differ from club to club, it is difficult to
determine, with a great deal of precision, the actual orientation
and speed of a club head simply by relying upon light reflected
from the club head into one or more arrays of detectors. In
accordance with the principles of the present invention, the use of
a retroreflective strip minimizes the uncertainties associated with
the use of light reflected directly from a club head and thereby
allows for precise determination of club head speed and
orientation. Although a system in accordance with the principles of
the present invention could operate successfully with a reflective
strip having any orientation relative to the club face 302, as long
as the orientation was known, in this illustrative embodiment the
long axis of the reflective strip is oriented parallel to the face
of the club. By orienting the reflective strip in this manner, the
system needn't transform data between a club face-centered
coordinate system and a reflective strip-centered coordinate
system. An alignment tool 307 in accordance with the principles of
the present invention may be employed to ensure that the strip 212
is aligned parallel to the club face and with the sweet spot of the
club face. FIG. 3b includes retroreflective strips 212, light
absorbing material in the form of black electrical tape 213, and a
reflective strip alignment tool 307. FIG. 3c illustrates the bottom
surface of a club head with black electrical tape 213 applied in
accordance with the principles of the present invention.
[0049] FIG. 3h illustrates an alignment tool in accordance with the
principles of the present invention in greater detail. The
applicator 307, which, in this illustrative embodiment is composed
of a pliable, resilient, material such as polystyrene or
polypropylene, includes a substantially rectangular member 310
having an aperture 312 for accepting a reflective strip that is to
be applied to a club head 211. One or more tabs 314 are connected
to the member 310 via a pliable joint 316, which joint may be
created by forming a weakened line of material. The "weakened line"
may be achieved by thinning the material, for example. Although two
tabs are shown in this illustrative embodiment, any number of tabs,
including a single tab running the entire length of the rectangular
member, may be employed in accordance with the principles of the
present invention. In operation, the tabs 314 are bent along the
face of the club 302, as illustrated in FIG. 3e, centered on the
club face's sweet spot. The aperture 312 is thereby positioned over
the applied absorbent surface 213, with its long axis aligned with
the club face 302. Although the retroreflective material may be
coupled to a club head through any means, including semiperminant
means, such as molding, soldering, etc., the use of retroreflective
tape allows a golfer to apply the material to clubs he already owns
and uses for playing golf.
[0050] FIG. 3f illustrates the application of a reflective strip
212 to the absorbent surface 213. In this illustrative embodiment
the reflective strip 212 includes a retroreflective surface with an
adhesive backing. The strip's adhesive backing is exposed before
placing the strip within the aperture 312 and, consequently, when
firmly positioned within the aperture 312, the strip adheres to the
absorbent material 213 and remains affixed to the material 213 when
the applicator 307 is removed, as illustrated in FIG. 3G.
[0051] FIG. 4 provides a more detailed view of a golf swing
analysis system sensor housing 200 in accordance with the
principles of the present invention. Sensors are arranged within
the housing as follows. Sensors 204a are positioned at the trigger
row of the housing. The sensors 204a include three emitter/detector
pairs. One of the emitter detector pairs is positioned along a
center line that it shares with the ball support 205. The other two
of the emitter/detector pairs are equally spaced on either side of
the middle emitter/detector pairs. Among other functions, this
group of sensors 204a operates as a "trigger" for the remaining
sensors, applying power to the emitters of the remaining sensors
only when a trigger event, indicating the passage of a golf club
head, has occurred. A linear array of eleven emitters and ten
detectors 204b is positioned transverse to the golf club swing path
approximately 1.25 inches closer to the golf ball support 205 than
the trigger array of sensors 204a. This array 204b is the entrance
row of sensors. Angled sensor array 204c is arranged with two pairs
of emitters and detectors, each pair parallel to the major axis of
the housing 200, with a pair aligned to either side of the ball
support 205. In an illustrative embodiment the angled emitter
detectors are positioned at an angle of 30 degrees with the upper
surface 202a of the housing 200. Such and alignment permits a
system in accordance with the principles of the present invention
to determine the height of a club head as it passes overhead. The
array 204d of four emitters and five detectors is positioned
transverse to the club swing path approximately four inches closer
to the ball support than the trigger array 204a. This, the contact
row of sensors, is positioned close enough to the ball support 205
to detect club swing information coincident with, or just before,
contact between a club face and the golf ball. That is, being
within 1.5 inches of the support 205 in the illustrative
embodiment, the trailing edge of the retrorflective strip passes
over the array substantially concurrent with the time the ball is
being struck and, consequently, data related from that array is
data at the time of impact. Another angled sensors array 204e is
arranged with two pairs of emitters and detectors, each pair
parallel to the major axis of the housing 200, with a pair aligned
to either side of and equidistant from the major axis that passes
through the center of the ball support. Additionally, in this
illustrative embodiment, the angled arrays 204c and 204e are
positioned an equal distance, d, of approximately three and one
half inches to either side of the ball support 205 and
perpendicular to the major axis of the housing 200. An exit row of
sensors 204f includes eleven emitters and ten detectors arranged
transverse to the club swing path 216 and a distance d2
approximately four and one half inches from the ball support 205
(that is, approximately the same distance from, but on the opposite
side of, the ball support as the sensor array 204b). In this
illustrative embodiment, a signal light in the form of an LED 204g
is positioned in close proximity to the center of the three
emitter/detector pairs that form the sensor array 204a. This
embodiment of a sports swing analysis system employs the LED to
indicate to a user whether the user is operating in a "putting"
mode or not.
[0052] The schematic representations of FIGS. 5a, 5b, and 5c
illustrate in greater detail the operation of "angled arrays" 204c
and 204e. The "ray tracing" representations of FIGS. 5a and 5b
contrast the reflection from an "ordinary reflector" (FIG. 5a) with
reflection from a retroreflector (FIG. 5b) as employed in this
illustrative embodiment. In FIG. 5a a ray of light emitted by
emitter e travels along a path P1 toward reflector R and is
reflected in the familiar "angle of incidence equals angle of
reflection" mode along path P2. In this representation a detector D
has an acceptance angle .theta. which precludes the detection of
light traveling along the reflected path P2. If detector D and
emitter E were employed as one of the angled emitter/detector pairs
of arrays 204c and 204e and the reflector R were employed as the
reflective material coupled to the club head 211, light emitted by
the emitter E would not be detected by the detector D as the club
head 211 passed over the pair along the path 216.
[0053] In contrast, the ray tracing of FIG. 5b illustrates the use
of a retroreflective material, as previously described. In this
illustrative example, light emitted by the emitter E travels along
the path P1 to the surface of the retroreflective material RET
where it is reflected along the path P2. Because the
retroreflective material does not reflect light according to the
"angle of incidence equals the angle of reflection", but, rather,
along a path P2 much closer to the original path P1, a detector
having the same acceptance angle, .theta., (or an even narrower
acceptance angle), will, in this instance, receive the reflected
light as the club head passes over the detectors along the path
216.
[0054] The side schematic representation of FIG. 5c depicts the use
of a retroreflective strip in concert with angled emitter/detector
pairs to determine the height of a golf club head above the top
surface 202a of the housing 202. Detector/emitter arrays 204a-204f
are as previously described. A vertical broken line 500 represents
the centerline of light emitted from the emitters 204be. As the
golf club 210 passes over the array 204b, light emitted from the
array strikes the bottom of the golf club's head. As the club
proceeds along the path 216 emitted light will strike absorbent
material for some period of time, then retrorefective material,
then absorbent material. That is, if the entire bottom surface of
the golf club is covered by a light absorbent material, such as the
dark electrical tape described, as previously described, with a
strip of retroreflective material applied over the tape, black tape
will pass over the array 204b, followed by the retroreflective
material, which is then followed by more black tape. The same
sequence of absorbent, reflective, and absorbent material will
apply to the angled array 204c. The light amplitude pattern of
dark, light, dark, received at the detectors is employed by the
system to recognize the passage of a golf club head and to
distinguish such a passage from ambient light, the passage of
shadows, and other spurious events.
[0055] In one aspect of a system in accordance with the principles
of the present invention, if the width of the reflective strip 212
and the height of the strip are known, the system may determine the
speed of the club head by dividing the time required for the
passage of the strip into the width of the strip. That is, given a
pair of light amplitude transitions that represent the passage of
the leading and trailing edges of the reflective strip, the system
divides width of the strip by the time between the transition pair.
A secondary correction can be made to correct for the spreading of
the beams with distance, since the height is known. In an
illustrative example, the width of the strip is 0.25 inches and the
system treats club head speeds between 10 mph and 220 mph
(corresponding, respectively, to 1420 microsecond and 64.6
microsecond intervals between leading and trailing edges) as valid
speeds. That is, the apparent club head speed is used, in
conjunction with other parameter values, to determine whether
variations in light amplitude received at the detectors are the
result of emitted light being reflected by a club head as it passes
over the sensor arrays, or the variations are due to other,
extraneous, processes. Other, slower, speeds may be denominated
valid in a putting mode, for example.
[0056] The system may record the time required for the club head to
pass from above the array 204b until the club head intersects with
the path P1 of light emitted from the angled array 204c. Because
the club head speed has already been determined (that is, by
dividing the width of the strip 212 by the time between light level
transitions corresponding to the passage of the leading and
trailing edges of the strip 212), the distance D1 between the
points of intersection of the club head with the vertical line from
the array 204b and the angled line P1 from the angled array 204c
may be determined by the system by multiplying the time between
those points of intersection by the speed of the club head. By
subtracting the distance D3 between the arrays 204b and 204c from
the distance D1, the system determines the distance D2. Given the
angle .phi. and the distance D2, the system may determine the
height H. Such measurements and corresponding height determinations
may be made for both the heel and toe of the club head, using,
respectively, the arrays closer and farther from the location of a
golfer (this proximity of the sensor arrays will vary according to
whether the user's stance is left-handed or right-handed).
[0057] Turning now to FIG. 6, the signal generation and processing
functional block 104 is discussed in greater detail. A controller
600, which may be composed of electronic circuitry that includes a
microprocessor or microcontroller, for example, provides drive
signals for the systems' emitters through an emitter interface 602.
Two or more emitters may be controlled with the same signal so
that, for example, the emitters in the array 204c may all be turned
on and off at the same time. The controller 600 also controls the
operation of a mode indicator interace 602, which, in this
illustrative embodiment, controls the operation of putting mode LED
204g. A detector interface 606 receives signals from the various
detectors and passes them along to a differentiator 608. The
differentiator 608 may be implemented in a variety of circuit
configurations and may take the form of AC coupling of detector
signals from the detector interface 606 to comparator circuitry
610. The comparator circuitry 610 converts the differentiated
detector signal to digital form for processing by the controller
600.
[0058] FIG. 7 illustrates the system architecture for a computer
system 700 on which a portion of the invention may be implemented.
The exemplary computer system of FIG. 7 is for descriptive purposes
only. Although the description may refer to terms commonly used in
describing particular computer systems, the description and
concepts equally apply to other systems, including systems having
architectures dissimilar to FIG. 7.
[0059] Computer system 700 includes a central processing unit (CPU)
705, which may be implemented with a conventional microprocessor, a
random access memory (RAM) 710 for temporary storage of
information, and a read only memory (ROM) 715 for permanent storage
of information. A memory controller 720 is provided for controlling
RAM 710.
[0060] A bus 730 interconnects the components of computer system
700. A bus controller 725 is provided for controlling bus 730. An
interrupt controller 735 is used for receiving and processing
various interrupt signals from the system components.
[0061] Mass storage may be provided by diskette 742, CD ROM 747, or
hard drive 752. Data and software may be exchanged with computer
system 700 via removable media such as diskette 742 and CD ROM 747.
Diskette 742 is insertable into diskette drive 741 which is, in
turn, connected to bus 730 by a controller 740. Similarly, CD ROM
747 is insertable into CD ROM drive 746 which is, in turn,
connected to bus 730 by controller 745. Hard disc 752 is part of a
fixed disc drive 751 which is connected to bus 730 by controller
750. User input to computer system 700 may be provided by a number
of devices. For example, a keyboard 756 and mouse 757 are connected
to bus 730 by controller 755. An audio transducer 796, which may
act as both a microphone and a speaker, is connected to bus 730 by
audio controller 797, as illustrated. It will be obvious to those
reasonably skilled in the art that other input devices, such as a
pen and/or tabloid may be connected to bus 730 and an appropriate
controller and software, as required. DMA controller 760 is
provided for performing direct memory access to RAM 710. A visual
display is generated by video controller 765 which controls video
display 770. Computer system 700 also includes a communications
adaptor 790 which allows the system to be interconnected to a local
area network (LAN) or a wide area network (WAN), schematically
illustrated by bus 791 and network 795. An input interface 799
operates in conjunction with an input device 793 to permit a user
to send information, whether command and control, data, or other
types of information, to the system 700. The input device and
interface may be any of a number of common interface devices, such
as a joystick, a touch-pad, a touch-screen, a speech-recognition
device, or other known input device.
[0062] Operation of computer system 700 is generally controlled and
coordinated by operating system software. The operating system
controls allocation of system resources and performs tasks such as
processing scheduling, memory management, networking, and I/O
services, among things. In particular, an operating system resident
in system memory and running on CPU 705 coordinates the operation
of the other elements of computer system 700. The present invention
may be implemented with any number of operating systems, including
commercially available operating systems. One or more applications,
such may also run on the CPU 705. If the operating system is a true
multitasking operating system, multiple applications may execute
simultaneously. An interface controller 733 may be employed, for
example, to communicate with the controller 600.
[0063] The flow chart of FIG. 8 illustrates the basic processes of
a swing analysis system in accordance with the principles of the
present invention. A portion of such processes may be implemented
on a computer system such as computer system 700 described in the
discussion related to FIG. 7. The process begins in step 800 and
proceeds from there to step 802 where the system determines whether
a trigger event has occurred. In an illustrative golf swing
analysis embodiment, emitters associated with entrance row sensors
204a sensors are turned "on" all the time the system is being used
and other sensors remain off until after a trigger event occurs. An
event that indicates the passage of a golf club head over the
sensors is detected by the detection and signal processing systems,
previously described. In this illustrative embodiment, the
detection of two light amplitude transitions, corresponding to the
passage of the leading and trailing edges of a retroreflective
strip coupled to a club head, qualifies as such a triggering event.
In step 802 the computer system 700 (upon which the analysis,
control, and interface system 106 may be implemented) polls a
trigger processing function to determine whether such an event has
occurred. If no trigger event has occurred, the process proceeds to
step 803 where the system determines whether it is to continue and,
if not, the process proceeds to end in step 816. The decision to
end the process may be made on the basis of user interaction or by
virtue of the exhaustion of a process timeout clock, for
example.
[0064] If a trigger event has occurred and been detected in step
802, the process proceeds to step 804 where data from the trigger
event is gathered. In an illustrative embodiment, data is gathered
by turning on all of the systems' sensors, sampling data from each
of the sensors (that is, all the detectors in all the arrays,
204a-204f) for a predetermined period of time at a predetermined
rate. Whenever there is a state change (that is, a change in a
comparator output corresponding to a reflected light-level
transition associated with the passage of a leading or trailing
edge of a reflective strip), the system records the time of the
transition. Transition data (that is, time of transition and the
identity of the detector that experiences the transition) is
accumulated until the predetermined time has elapsed. In an
illustrative embodiment, the data accumulation time is determined
by the time required for a club head to travel the distance from
the entrance row sensors 204a to the exit row sensors 204b. This
"travel time" may be employed by a system in accordance with the
principles of the present invention in a variety of ways. For
example, because the emitters associated with every sensor array
other than the trigger array are turned on only during this period,
more power may be applied to the emitters than would be the case if
they were constantly "scanning" for club heads. That is, the
minimum timing interval is not limited, as some conventional
systems' is, by the need to turn off, or otherwise limit the power
supplied to emitters that are constantly scanning because their
systems have no trigger-detection capability. That is, such
conventional systems continuously pulse power to their emitters at
a rate that prevents the emitters from overheating; a system in
accordance with the principles of the present invention, because it
only operates the emitters when an event of interest has been
detected by a trigger event, can operate the emitters at full
power, without pulsing, for a length of time consonant with the
passage of a club head over the sensor arrays. Not only does the
system avoid cycling the emitters (that is, cycling the emitters on
an off) during the time a club head is passing over the housing
200, and thereby increase the resolution of the system (that is,
the number of data samples the system may be able to obtain for a
given period of time), operating at higher power levels provides
more certainty in distinguishing reflections of interest from
extraneous light. Additionally, by limiting the data accumulation
time, the system reinforces limits placed on the range of club head
speeds it will analyze.
[0065] In an illustrative embodiment, the predetermined time set
for accumulating data is 0.1 seconds. Because the distance between
the entrance and exit rows of sensors is less than a foot, 0.1
seconds provides for the accumulation of sensor data for any club
speed of interest. That is, at club speeds of 220 mph and 10 mph, a
club head would cover the distance between entrance and exit row
sensors in less than 0.0031 seconds and 0.0682 seconds,
respectively. Consequently, 0.1 seconds provides a safe margin of
time to record data of interest while allowing the emitters to
operate at full power for a period of time that is brief enough to
insure their safe operation. Each of the sensors delivers its
output to the controller 600. In an illustrative embodiment the
signal generation and processing 104 identifies the input
associated with each sensor. Such identification may be
implemented, for example, through use of multiplexing techniques,
for example. The controller is also configured to control operation
of the sensors and to provide clocking information associated with
received signals. In this illustrative embodiment, the controller
is configured to identify which sensors have transmitted signals
indicating the time of their actuation at a frequency of 100 kHz
for a corresponding timing rate of approximately 0.00001 second
intervals. In this illustrative embodiment, the controller is a PIC
RISC microcontroller, available from Microchip, Inc.
[0066] Data files are fed from the controller to the computer via
an interface, such as the interface controller 733 described in the
discussion related to FIG. 7. The controller monitors the sensors
for change in state events and creates data files containing
sequences of change of state events, along with their associated
timestamps. As used herein, a change in state event occurs whenever
the leading or trailing edge of the reflective tape passes over a
sensor device. Each file includes at least a particular sensor
device identifier, a status field, and a time of actuation field.
The sensor device identifier may be any sort of identifier
recognizable by the program. The status field may be an ON/OFF
indication, for example, a "1" or a "0", representing whether the
particular device was actuated during a swing. The time field is
filled with the time of actuation, as compared to the time of
actuation of other sensor devices (for example, the time from
activation of a trigger device).
[0067] The computer is programmed to assess whether a sufficient
number of individual sensor devices were activated fro the purpose
of making a swing assessment. The required number is a programming
option. If an insufficient number has been filled, that may
indicate that the swing path was wild or incomplete and the
analysis process is terminated and the user advised accordingly.
The analysis first determines whether a possible club head "image"
has been detected on the entrance and exit rows. If both images are
present, a preliminary club head speed calculation is made, based
on measured time and known distance between the rows. If a
sufficient number of fields have been filled, the analysis process
continues by determining whether data from the sensors confirm a
minimum gross club head speed has been detected. That initial speed
calculation is preliminarily made by calculating the spacing
differential between particular activated ones of the sensors and
dividing that number by the time lapse between activation of such
sensors. The minimum club speed could be any value, such as ten
mph, for example, that helps to determine whether a legitimate
swing has occurred. Alternatively, no minimum speed would be set
for analyzing putting strokes. If that minimum speed has not been
achieved, the analysis is terminated and the user so advised. If
the minimum speed has been reached and a sufficient number of
sensors have been actuated, a file is created from the temporary
folders data for detail analysis related to swing
characteristics.
[0068] After gathering data in step 804, the process proceeds to
decision step 806, where the system determines whether to proceed
in putting mode. This decision is based upon the data gathered in
step 804. In an illustrative embodiment, a club head that passes
over the center trigger of the trigger row 204a, then over a sensor
at the extreme end of the entrance row and no other sensors,
initiates the putting mode. If the putting mode is not activated,
the process proceeds to step 808 where the data gathered in step
804 is examined to determine whether any transitions were recorded
in the detectors associated with the exit row sensors 204f. If
transitions were recorded in the exit row, the process proceeds to
step 810, where recorded data is forwarded for processing in step
811.
[0069] In step 811, the data is used to calculate various
parameters related to the mechanics of the swung club. In
accordance with the principles of the present invention, those
parameters may include: swing path angle, club head speed, club
head angle, lateral alignment, club head height, loft angle, ball
flight path, shot distance, ball spin, swing tempo, ball stroke
location on the club face, club face angle, and the effective club
head speed. In an illustrative embodiment a swing analysis system
in accordance with the principles of the present invention employs
a strip of retrorflective material attached to the head of a golf
club. Due to the properties of retroreflective material, previously
described, the system's sensor response is substantially
independent of the angle of the bottom of a passing golf club head.
Consequently, for example, club heads with convex bottoms, the
reflective sensing of which would pose a problem if using
conventional reflective material, are readily sensed using
retroreflective material. Similarly, although various stance errors
on the part of a user (for example, hands forward or back, standing
too close or too far away from the ball) may cause the bottom of
the club head to be other than horizontal, the use of
retroreflective material allows the system to operate well, since
emitted light that strikes the surface of the retroreflective
material is returned substantially along the path it took from its
source. The retroreflective material also allows the use of the
narrowest possible emitter light beams and the narrowest possible
detector sensitivity area, the combination of which maximizes the
precision of the system's position measurements. As a result,
time-stamped data corresponds exactly to the edges of the
reflective tape passing directly over the particular detector.
[0070] The system organizes "on" and "off" edges, corresponding
with leading and trailing edges of a retroreflective strip sensed
by a particular sensor. Such on/off pairs are referred to as an
"event." The system organizes patterns of overlapping events in the
sensor rows as "club signatures." For example, if a club head were
traveling at 100 mph, perfectly square, and along a path that is
directly down the center of the housing, one "pattern of
overlapping events" would be that the five middle detectors in
entrance row 204b would all turn on at approximately the same time
and all would turn off approximately 142.times.10.sup.-6 seconds
later (assuming a 0.25 inch wide retroreflective strip and assuming
negligible beam spread). In an illustrative embodiment in which all
the emitters are turned on at a high power level for 0.1 seconds in
response to a trigger event and the corresponding detector outputs
are sampled for that 0.1 second period at 10.times.10.sup.-6 second
intervals, a significant number (fourteen) of "on" samples should
be obtained, thereby providing a high confidence level that the
item being detected is, indeed a reflective strip of interest and
not merely artifact. Alternatively, the system may search for a
threshold number (four or five, for example) of overlapping events
occurring on the entrance and exit row sensors. That is, the system
may verify good data by examining turn on/turn off pairs that occur
at approximately the same time within a plurality of detectors
within the same sensor row and determining that those events having
durations corresponding to an appropriate speed. Events within each
row may also be compared with events detected within a plurality of
rows.
[0071] In this illustrative embodiment "events" (that is, turn
on/turn off pairs) are stored, along with a detector identifier and
timestamp. By storing only this transition-related data, the system
requires a great deal less memory than it would if all the data
collected from all the detectors were stored. Additionally, the
system can perform calculations related to the detector data much
more quickly if it operates on the stored transition-related data
than it would if it had to operate on the much more extensive "raw"
data produced by all the detectors for an entire 0.1 second
sampling period.
[0072] The system calculates the club face angle by associating the
time difference between detector transitions within a pattern of
events. For example, if a club face is swung approximately 7.2
degrees open, the end of the reflective strip closer to the golfer
will create a transition in a row of detectors while the other end
of the reflective strip still has approximately 0.25 inches to go
before reaching the row of detectors (assuming a 2 inch long
reflective strip, arcsin 0.25/2.0=7.2 degrees) At a club head speed
of 100 mph, the 0.25 inch offset corresponds to a
142.times.10.sup.-6 delay between transition events associated with
either end of the reflective strip. Similarly, a 7.2 degree closed
club face would create the same delay, but with the end of the
reflective strip farther from the golfer passing over a row of
detectors before the end closer to the golfer.
[0073] In an illustrative embodiment the swing analysis system
calculates the swing path angle, determining which detectors in
which rows correspond to the path of the same reflective strip
feature. For example, the system may determine which detector
signal transitions in detector arrays 204b and 204f correspond to
reflections from the end of the reflective strip closest to the
golfer, farthest from the golfer, or the system may "average"
detector responses to approximate detector transitions due to the
passage of the center of the strip. Once a path is determined, for
example, the center of the strip took a course that passed over a
detector at one extreme of the array 204b to the other extreme of
the array 204f. In this illustrative embodiment, that corresponds
to a movement across the housing of approximately 4.5 inches in the
course of transiting the nine inches between arrays 204b and 204f.
The system calculates the path angle as the arctan of 4.5/9, or,
26.6 degrees. This value would be associated with a path attribute
of inside/out or outside/in, depending upon whether the club head
traveled, respectively, from a point closer to the golfer to a
point farther from the golfer or from a point farther from the
golfer to a point closer to the golfer.
[0074] In an illustrative embodiment, the swing analysis system
calculates the club head speed by determining the "event duration"
(that is, the time between a turn on and a turn off transition).
This event time could be associated with detectors in the trigger
row 204a, for example. As previously noted, if the width of the
retroreflective material is known, the system can calculate the
club head speed as the material width divided by the event
duration. Additionally, the system may calculate the club head
speed as the distance between any two sets of arrays divided by the
corresponding delay between events. The system may make also employ
averaging and/or smoothing algorithms to better approximate the
club head speed. Because the system determines overlapping events
corresponding to club signatures on all sensor rows, the system may
employ data (that is, timestamps and detector identifications)
associated with those signature events to determine speed, path
angle, etc. The system may set acceptable timing and event duration
ranges, and discard data associated with out-of-limits edge
detection. This allows the system to "filter out" spurious data.
The process of searching out patterns of overlapping events and
discarding out-of-limits data may be repeated until, for example,
the calculated results fall within a predetermined confidence
level. In effect, a system in accordance with the principles of the
present invention sets a window for the most likely duration of
valid events for a given club head speed. If the speed and duration
don't match, extreme events are discarded and the system
recalculates the speed and duration of the remaining events until
the system has identified swing events that fit within the norm,
or, until all the collected events are discarded.
[0075] A system in accordance with the principles of the present
invention may employ the club head speed and face angle to compute
the ball spin, triangulation techniques such as previously
described to compute a club head's toe and heel height before and
after impact with a ball. The shot distance may calculated based on
the club selection, club head speed, swing path, face angle, and
point of contact on the club face. A ball's landing spot may be
calculated on the basis of ball flight distance, spin, and the
simulated course's terrain. In an illustrative embodiment, a
golfer's tempo is the time between his backswing and downswing. A
club's lateral alignment is determined by drawing an imaginary line
from the club center at the entrance row to the club center at the
exit row. The effective club head speed is determined, in this
illustrative example, by derating the club head speed according to
the degree to which the club face angle was off-square at the point
of impact.
[0076] From step 811, the process proceeds to step 812, where the
results of the calculations are displayed. In addition to
displaying results of the calculations, the system may provide
audio feedback and may provide a variety of display modes. Such
audio feedback may be employed by a user to be coached while
concentrating on the ball, his stance, his mechanics, without
looking at a display, for example. From step 812 the process
proceeds to step 814 where the system decides whether to continue
or not. This decision may be based upon user input or a system
timeout, for example. If the process is not to continue, it
proceeds to end in step 816. If the process is to continue, the
process returns to step 802 and, from there, as previously
described.
[0077] If, in step 808, the process determines that there had been
no events associated with sensors in the exit row, the system
concludes that the trigger event of step 802 is associated with a
player's backswing motion and the process proceeds to step 818. In
step 818 backswing data recorded in step 804 is sent to the
calculation process of step 819. In step 819 the swing analysis
system employs the time between two sequential trigger events,
associated with a club head passing over the trigger array 204a in
a reverse direction, followed by it's passage in the forward
direction, to calculate the player's backswing tempo. After
calculating the backswing parameters in step 819, the process
proceeds to step 812, where the backswing information is displayed,
and, from there, the process proceeds as previously described.
[0078] Returning to step 806, if the system determines that a
player's input indicates a desire to operate the system in the
putting mode, the process proceeds to step 820. In step 820 the
system gathers swing analysis data related to putting. Because
putting is considerably different from a "regular" swing (that is,
a tee shot, or chip shot, for example) the process of gathering
data related to a player's putting stroke is also considerably
different. For example, the expected clubhead speed is much slower
than that associated with a regular swing. Consequently, the
putting data-gathering process takes place on a much slower time
scale.
[0079] In an illustrative embodiment, once the putting mode is
entered, the system temporarily stores the state [that is,
"on"(detecting light), or "off"(not detecting light)] of all the
detectors in all the sensor arrays 204a-204f. Then, all the
emitters in all the sensor arrays are turned on and the state of
all the detectors in the sensor arrays is once again temporarily
stored. All the emitters are then turned off, and the most recently
stored state information for each of the detectors is compared to
the corresponding next-most recently stored state in order to
determine which, if any, of the detectors has undergone a change in
state. The system timestamps each change of state for each detector
in which a change of state is detected. The process of turning all
the emitters on, logging the state of each detector, and
timestamping each change of state continues until the end of the
putting process. The end of the process may be brought about by
virtue of user interaction or by a timeout, for example. In this
illustrative embodiment, the pulsing of emitters in the putting
mode takes place over an extended period of time in order to allow
for the relatively slow strokes related to putting. In the putting
mode, light level transitions are associated, not with the passage
of the leading and trailing edges of a reflective strip, as in the
normal mode of operation, but with reflections from a reflective
strip associated with the pulsing on and pulsing off of
emitters.
[0080] The system employs the timestamp list, as it does in other
modes of operation, to determine the motion of the club head. That
is, as previously described, a system in accordance with the
principles of the present invention computes the values of various
club head parameters, such as path angle, by examining the
sequential detection of club head features at sequential detector
locations. In this illustrative embodiment, those sequential
detections are stored in the form of a timestamp list. After
gathering the putting data in step 820, the process proceeds to
step 822 where the data is forwarded to the calculation process of
step 823. In step 823 the values of putting parameters are
calculated, then the process proceeds to step 812, where those
values are displayed. From step 812, the process proceeds as
previously described.
[0081] The computer is programmed to determine the swing path
angle, club head speed, club head angle, club head lateral
alignment, and club head toe and heel height before and after
impact and the club head loft. This information also enables the
system to calculate the ball strike location on the club face. In
addtion, the effective club head speed may be calculated. This
rating is calculated based on the ratio of the club head angle, the
relation of the club head to center, and the swing path to those
parameters for an idealized swing and multiplying that fraction by
the measured club head speed to obtain an overall or composite
swing rating. Furthermore, based on this information, the systems
calculates information about the shot that would have been taken if
a real golf ball had been hit by the swing. Such information
calculated includes the flight path of the ball, the distance of
the shot, the spin of the ball and the swing tempo. This
information enables the system to generate a three-dimensional
representation of the shot, which can then be superimposed on a
representation of a golf hole stored in the memory of the computer.
The system is able to apply the calculated information to a
standard golf hole, to a driving range simulation, and to a
practice putting green simulation, as described in greater detail
in the discussion related to the following Figures.
[0082] The calculated values may be displayed as textual
information, a simple graphic representation, a multimedia
representation, or any combination thereof on the display computer
device. The computer may, optionally, be programmed to retrieve
historical swing information associated with the current user,
another user who has used the system or another player, such as a
professional player or an "idealized" player swing attributes have
been stored on the computer for comparison purposes. The system may
be employed to analyze a player on a swing-by-swing basis, with
swing analysis data cleared after each shot, or the swing
information may be tied to a computer representation of a game
simulation. The swing information captured by the system may be
integrated into a course representation.
[0083] Such simulations are shown in FIGS. 9, 10, and 11. FIG. 9 is
a screen shot 900 of one hole of a 3-D golf course that the user
may play using the simulations calculated by the system 100. The
screen includes the representation of the hole as well as a window
which displays the information calculated by the system for each
shot taken by the user. Other displays permit the representation of
the hole being played and a window showing a representation of the
shot as seen from above and a window showing the shot as seen from
ground level. All of the data calculated by the system may be
represented either in text on the screen or in pictures that show
the shot in windows. The screen shot 900 illustrates data
presentation such as may displayed by a swing analysis system in
accordance with the principles of the present invention. In an
illustrative embodiment, the system operates in five display modes:
Practice Range, Practice Course, Practice Green, Course Game, and
Green Game. The Practice Green and Green Game display modes operate
in conjunction with the putting mode of data capture and analysis,
as described in the discussion related to FIG. 8. The Practice
Range, Practice Course, and Course Game display modes operate in
conjunction with the regular swing mode of data capture and
analysis, as described in greater detail in the discussion related
to FIG. 8. Toolbar buttons 902, 904, 906, and 908 allow a user to,
respectively, select the mode of play, select the club to use for
analysis, select the view to be displayed, and select other
options. In this illustrative example, information obtained by the
system's sensor arrays and conditioned and analyzed by the
controller has been passed to the computer for display. This
particular display simulates a driving range and the visual
feedback is organized in four windows. The largest window 910
includes graphical information that portrays the layout of a
driving range, with yard markers 912, and a trace 914 that
indicates the ball's trajectory.
[0084] A box 916 in the upper left corner of the window 910
includes textual information regarding a swing that has been
analyzed by the system. This information includes the distance the
ball has traveled (that is, the distance a ball would have traveled
according to the simulation conducted by the system based on the
information obtained from the sensor arrays and controller), in
this cases 214.1 yards. The box also lists the speed at which the
ball traveled, 74.9 mph, the swing tempo, 0.9 seconds (that is the
time of a user's backswing), left or right of center, 4.2 yards
(the distance at which the ball landed to the left or right of the
user's intended ball path), and the toe and heel heights of the
club relative to the "ground" (that is, to the upper surface of the
sensor housing). The toe and heel heights indicate whether the club
was angled in the vertical plane when the retroreflective strip
intersected the beams of the angled arrays, as described previously
described. The IN values are the heights of the club head toe and
heel before ball contact (related to measurements from arrays 204c)
and the OUT values are the heights of the club toe and heel after
ball contact (related to measurements from arrays 204e). The
"Penalty" value displayed at the bottom of the box 916 is computed
by the system to reflect a combination of factors, including how
far outside the club's sweet spot the ball was struck and the
terrain on the course (for example, whether the ball was being hit
from the rough).
[0085] A window 918 displays textual and graphical information
regarding the swing's face angle and swing path. The system
computes and displays the club's face angle before, after, and at
the point of contact with the ball. Data relating to these
positions are primarily obtained from the entrance 204b, contact
204d, and exit row 204f sensors, respectively, as previously
described. The face angle is given in degrees, along with an
indication of whether it is open, closed or square (that is, the
face angle is zero). A square club face is desired for most shots.
If a user is right handed and the face angle is open on contact,
the face of the club is perpendicular to a line point to the right
of the desired line of flight of the ball. If the face angle is
closed, the face is pointing to a line pointing to the left of the
desired line of flight of the ball. The IN/OUT swing path is also
given in degrees and is the path of the club across the sensor unit
200. A square swing angle cuts a path directly across the middle of
the swing sensor unit. For a right-handed golfer, an inside out
swing describes a path from the lower right hand corner to the
upper left hand corner in the window 918 and an outside in swing
path follows a path from the upper right to the lower left hand
corner of the window 918. This illustrative system displays a
confidence meter 919 in the window 918 to indicate to a user the
degree of confidence the system has in its calculations. The
system's confidence in its measurements and calculations may be
affected by light interfering with the sensors or errant swings,
for example, and the meter 919 provides the system with a way in
which to apprise a user of the system's view of the reliability of
its current measurements.
[0086] The window 920 displays, in both textual and graphical form,
a measurement (in degrees) of a swing path's variation, at the
point of impact with the ball, from an imaginary horizontal plane
(that is, a plane parallel to the plane of the top of the sensor
housing. The window 920 also displays a plurality of club head
heights. In this illustrative example, the displayed club head
heights are measured as the club approaches the ball (0.9 inches),
at the point of impact with the ball (0.2 inches), and after impact
with the ball (0.4 inches). The window 924 displays information
related to the location on the clubface at which the ball was
struck. In a graphical component of the display, a red cross marks
the impact point on the clubface and a textual display indicates
the distance between the impact point and the club's sweet spot.
The sweet spot is the ideal contact point on the club face, the
contact point that yields maximum distance and power. The in this
illustrative embodiment, penalties may be assigned to the
trajectory of a ball corresponding to the distance between the
actual point of impact and the desired point of impact (that is,
the sweet spot). The format of the information displayed in this
screen shot may be used, with minor modification, in a number of
the system's modes of operation. That is, it may be used in
conjunction with the Practice Range, Practice Course, and Course
Game modes, with minor modifications, such as changes to the
terrain and elimination of yard markers 912 in the Practice Course
and Course Game modes.
[0087] In an alternative mode of operation, the system may be used
to monitor a putting stroke. Since a golfer, when lining up a put,
may take several practice swings, the system must be able to
distinguish the practice swings from the actual putting stroke. In
an illustrative embodiment, the system is placed in a putting mode
by swinging a putter diagonally across arrays 204a and 204b. The
system then begins storing information received by the sensors in a
circular buffer for a predetermined period of time: ten seconds,
for example. Since the putting swings are much slower than a
regular swing, the system, in putting mode, operates at a lower
power for a greater period of time compared to the standard swing
mode described above. The system takes the last set of data stored
in the circular buffer and analyzes it to give the calculated
information for the put stroke.
[0088] The screen shot of FIG. 10 is of a display that provides
substantially the same information as the screen shot of FIG. 9,
except that this screen shot relates to data collected and analyzed
while the system is operated in its putting mode. The illustrative
embodiment's putting mode data gathering and analysis operations
may provide data for the Practice Green and Green Game display
modes. The box 916 provides a listing of the same type of
information, as do windows 918, 920, and 924. The trace 914
provides an indication of the balls trajectory that, unlike that of
FIG. 9, remains in contact with the ground. A box 1000 indicates
the lay of the terrain and the distance to the hole. A system in
accordance with the principles of the present invention may provide
a plurality of greens for user interaction. In this illustrative
embodiment, the Practice Green mode provides user interaction for
nine different greens, with each green featuring different putting
lengths. The system may be used to train a user to execute straight
putts. The system's user interface allows a user to line up his
sight for a putt. Depending upon the green and the lie of the ball,
the ideal stroke may be in a direct line to the hole, to the right
of the hole or to the left of the hole. In response to data
collected and processed by the sensor arrays, the computes the
trajectory of the user's shot, allowing for the slope of the green,
and the accuracy and power of the user's shot. Based on the
feedback displayed, as in FIG. 10, a user may modify his stance and
swing in order to hit the ball with a square swing path, a square
club face, and with the sweet spot of the club.
[0089] FIG. 11 is screen shot of a course overview available with
the Practice Course and Course Game modes of the system's
operation. In this illustrative embodiment, a user may select from
a variety of tee locations (e.g., pro, intermediate, beginner, or
women's tees), types of play, and other options. During a game,
players may start in a numerical sequence (e.g., 1, 2, 3, and 4)
and, on subsequent holes, the system will automatically determine
the order of shooting, based on the distance each shot lies from
the hole being played. The user interface is also configured to
allow a player to take a "Mulligan" and "whiff." If a player hits a
ball out-of-bounds, the player will be assessed a penalty stroke
and the ball will automatically be placed on the fairway at the
point where it crossed out of bounds.
[0090] In addition to the several views available corresponding to
shot type and analysis, the system allows a user to choose from
various views related to the travel of the ball, and these views
are available in a plurality of modes. In particular, a user may
choose, "still", "follow the ball", or "spin" views. In the "still"
view, the user observes the ball trajectory from a stationary
viewpoint corresponding to the place where he was standing when he
hit the ball. In the "follow the ball" view, the user's viewpoint
follows the ball, as thought tethered to the ball. And, in the
"spin" view, the viewpoint follows the ball and then spins to a
side view that travels along with the ball. The system's user
interface also allows a user to "fly over" the course at any time.
A fly over generates a "fly thru" of one or more holes from the
respective tee box to hole pin. In accordance with the principles
of the present invention, the system creates a three-dimensional
(3D) representation of the course upon which a user is playing and,
as a result, the views just described, which relate the flight of a
users golf ball to a 3D virtual golf course are available to a
user. The creation of the 3D virtual course and the ball-related
views may be implemented using animation and rendering techniques
known in the art.
[0091] The system allows a user to interact, through a keyboard or
a mouse, for example, with the user interface to thereby move the
viewpoint of the fly thru up or down in order to get a better view
of the hole. The user interface also allows a player to drop a ball
anywhere on the course in order to practice shots from the selected
location. The allows players to call up previous shots and to
thereby allow a player to review the stored shots, to compare the
shots, and to review the progress he may be making. A user may
select wood and iron tee heights (heights used whenever a shot is
hit with a driver or wood, or with an iron), and grass height (the
height used whenever the player hits from the grass with an un-teed
ball. This height information will be used by the system in
conjunction with data collected from the sensor arrays to determine
the location on the club face that strikes a ball when the player
takes a shot. At the option of a user, the system may align the
putt direction to a "hint line", allowing a user to get a feel for
how to play the lay of a putt.
[0092] The system provides audio feedback which a user might employ
during practice to obtain feedback while focusing on his shots.
That is, a user may select a mode that announces the data and swing
analysis, such as is displayed in the various display windows
previously discussed. By announcing the data through use of a
speaker, such as speaker 770, a user may, for example, take a shot,
hear the analysis of the shot, and line up his next shot, all while
focusing on his ball and club, without resorting to viewing the
system's display output.
[0093] The perspective view of FIG. 12a is a more detailed view of
a mat 215 that may be employed in a swing analysis system in
accordance with the principles of the present invention. In this
illustrative embodiment, the mat 215 includes top and bottom layers
1202 and 1204, respectively. The top layer 1202 is composed of a
resilient material, such as a uniback simulated grass surface,
available from Grass-Tex, Inc., Dalton Ga. that emulates the
texture and appearance of grass. Both layers are made of durable
resilient materials. The bottom layer may be made of an EVA foam,
available from Der-Tex, Saco Me. The thickness of the mat T, is
selected to be approximately the same thickness as that of the
sensor housing, thereby supporting a user at approximately the same
level as the top surface of the sensor housing. The head 1208 and
foot 1210 of the mat are associated with the ends of the sensor
housing that include, respectively, the exit and entrance row
sensors. The drawing is not to scale. An aperture 1206 is designed
to receive the sensor housing 202. Because the mat is made of
resilient flexible materials, it may be folded or rolled for
convenient packaging and transportation. FIG. 12b provides a
sectional view from the foot 1210 of the mat 215. In this
illustrative embodiment, the top layer 1202 includes three sections
1212, 1214, and 1216, that extend the length of the mat, from head
to foot. The sections 1212, 1214, and 1216, are coupled to the
bottom layer 1202, in an illustrative embodiment, by an adhesive
such as a heat-cured adhesive. Adhesive-free voids 1218, and 1220
are left on either side of the top section edges that form joints
between top sections 1212 and 1214 and between top sections 1214
and 1216. The adhesive voids run the length of the mat 215. In this
illustrative embodiment, the combination of adhesive voids 1218 and
1220, flexible, resilient materials used for top 1202 and bottom
1204 layers, and the three-section composition of the top layer
1202, permit the mat 215 to be readily folded "in three" for
packaging and transportation, along the joints formed between top
sections 1212 and 1214 and between top sections 1214 and 1216.
[0094] A software implementation of the above described
embodiment(s) may comprise a series of computer instructions either
fixed on a tangible medium, such as a computer readable media, e.g.
diskette 742, CD-ROM 747, ROM 715, or fixed disc 752 of FIG. 2, or
transmittable to a computer system, via a modem or other interface
device, such as communications adapter 790 connected to the network
795 over a medium 791. Medium 791 can be either a tangible medium,
including but not limited to, optical or analog communications
lines, or may be implemented with wireless techniques, including
but not limited to microwave, infrared or other transmission
techniques. The series of computer instructions embodies all or
part of the functionality previously described herein with respect
to the invention. Those skilled in the art will appreciate that
such computer instructions can be written in a number of
programming languages for use with many computer architectures or
operating systems. Further, such instructions may be stored using
any memory technology, present or future, including, but not
limited to, semiconductor, magnetic, optical or other memory
devices, or transmitted using any communications technology,
present or future, including but not limited to optical, infrared,
microwave, or other transmission technologies. It is contemplated
that such a computer program product may be distributed as a
removable media with accompanying printed or electronic
documentation, e.g., shrink wrapped software, preloaded with a
computer system, e.g., on system ROM or fixed disc, or distributed
from a server or electronic bulletin board over a network, e.g.,
the Internet or World Wide Web.
[0095] Although various exemplary embodiments of the invention have
been disclosed, it will be apparent to those skilled in the art
that various changes and modifications can be made which will
achieve some of the advantages of the invention without departing
from the spirit and scope of the invention. It will be obvious to
those reasonably skilled in the art that other components
performing the same functions may be suitably substituted. Further,
the methods of the invention may be achieved in either all software
implementations, using the appropriate object or processor
instructions, or in hybrid implementations that utilize a
combination of hardware logic, software logic and/or firmware to
achieve the same results. The specific configuration of logic
and/or instructions utilized to achieve a particular function, as
well as other modifications to the inventive concept are intended
to be covered by the appended claims.
[0096] The foregoing description of specific embodiments of the
invention has been presented for the purposes of illustration and
description. It is not intended to be exhaustive or to limit the
invention to the precise forms disclosed, and many modifications
and variations are possible in light of the above teachings. The
embodiments were chosen and described to best explain the
principles of the invention and its practical application, and to
thereby enable others skilled in the art to best utilize the
invention. It is intended that the scope of the invention be
limited only by the claims appended hereto.
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