U.S. patent application number 10/884396 was filed with the patent office on 2005-02-03 for apparatus and method for monitoring launch parameters of a launched sports object.
Invention is credited to Pao, Yi-Ching.
Application Number | 20050026710 10/884396 |
Document ID | / |
Family ID | 34108059 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050026710 |
Kind Code |
A1 |
Pao, Yi-Ching |
February 3, 2005 |
Apparatus and method for monitoring launch parameters of a launched
sports object
Abstract
A video image acquisition apparatus is disclosed. The apparatus
has one or multiple digital cameras taking images of a flying golf
ball created by at least two flashes or strobes of light on
continuous video mode at a predetermined frame rate. Each image
frame is then subtracted from the background and compared to
determine the existence of the ball image in flight thus
eliminating a dependency upon the camera shutter speed which must
be synchronized with the flashes in prior art design. Furthermore,
another video image acquisition apparatus is also disclosed that
consists of at least two video cameras taking images of flying golf
balls created by at least two flashes or strobes of light at
predetermined time intervals. The apparatus then applies
triangulate calculation of the two camera images to determine the
exact physical locations of the flying golf balls in space at a
given time of flight.
Inventors: |
Pao, Yi-Ching; (Los Altos
Hills, CA) |
Correspondence
Address: |
C.P. Chang
c/o Pacific Law Group LLP
Suite 525
224 Airport Parkway
San Jose
CA
95110
US
|
Family ID: |
34108059 |
Appl. No.: |
10/884396 |
Filed: |
July 1, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60491886 |
Aug 1, 2003 |
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Current U.S.
Class: |
473/141 |
Current CPC
Class: |
A63B 2102/32 20151001;
A63B 2220/806 20130101; A63B 71/06 20130101; A63B 2220/05 20130101;
A63B 43/008 20130101; A63B 69/3658 20130101; A63B 24/0021 20130101;
A63B 2024/0034 20130101 |
Class at
Publication: |
473/141 |
International
Class: |
A63B 069/36 |
Claims
What is claimed is:
1. An electronic imaging apparatus for monitoring the early flight
of a launched sports object, the imaging apparatus comprising: (a)
A triggerable flash device for emanating at least two flashed
illuminations, separated by a predetermined time interval, at the
sports object thus creating at least two corresponding flight
scenes of the sports object; (b) an electronic camera system,
located near the launched sports object and activated under a
continuous video mode, for capturing image frame data corresponding
to said flight scenes; and (c) a computing device coupled to the
electronic camera system for acquiring, processing and analyzing
the captured image frame data into displayable sports object launch
parameters
2. The imaging apparatus of claim 1 further comprises an image
frame background subtraction mechanism to freeze and recognize the
sports object image in flight for the processing and analyzing of
the captured image frame data.
3. The imaging apparatus of claim 2 further comprises an image
enhancement mechanism to enhance the contrast and image sharpness
of the sports object image from the captured image frame data for
the processing and analyzing of the captured image frame data.
4. The imaging apparatus of claim 1 wherein said flash device is
triggered with an acoustic, an optical or an electronic device.
5. The imaging apparatus of claim 1 wherein said sports object is a
golf ball and wherein said launch parameters comprise a launch
angle, a launch speed and a launch azimuth in degrees of push or
Pull.
6. The imaging apparatus of claim 5 wherein the surface of said
golf ball further comprises one or two markings whereby, based upon
the location and orientation of the one or two markings contained
in the captured image frame data, the computing device determines
additional sports object launch parameters of back-spin RPM
(revolutions per minute), side-spin RPM and rifle-spin RPM.
7. The imaging apparatus of claim 5 wherein the shape of each of
said markings is a bar or a line.
8. The imaging apparatus of claim 1 wherein said electronic camera
system further comprises at least one digital CMOS or CCD camera
located with a predetermined spatial relationship with a pre-launch
position of the sports object.
9. An electronic imaging apparatus for monitoring the early flight
of a launched sports object, the imaging apparatus comprising: (a)
A triggerable flash device for emanating at least two flashed
illuminations, separated by a predetermined time interval, at the
sports object thus creating at least two corresponding flight
scenes of the sports object; (b) an electronic camera system
located near the launched sports object but spaced from it by a
predetermined distance D.sub.cm transverse to the sports object
launch direction, for capturing image frame data corresponding to
said flight scenes, the camera system further comprising at least a
first and a second camera wherein the second camera being mounted
essentially vertically above and separated from the first camera by
a predetermined distance D.sub.sp thereby creating a corresponding
difference in golf ball viewing angle .DELTA..theta. between the
first camera and the second camera; and (c) a computing device
coupled to the electronic camera system for acquiring, processing
and analyzing the captured image frame data into displayable sports
object launch parameters whereby, owing to the creation of said
difference in golf ball viewing angle .DELTA..theta., the
repeatability and accuracy of said launch parameters can be
correspondingly improved.
10. The imaging apparatus of claim 9 wherein said first camera is
mounted near the ground.
11. The imaging apparatus of claim 9 wherein said distance D.sub.sp
is set to be greater than an equivalent diameter of the sports
object.
12. The imaging apparatus of claim 9 wherein said sports object is
a golf ball having a diameter of about 1.7 inches.
13. The imaging apparatus of claim 12 wherein said distance
D.sub.cm is set within a range from about 12 to about 24 inches and
said distance D.sub.sp is set within a range from about 4 to about
8 inches thereby creating a difference in golf ball viewing angle
.DELTA..theta. between about 9 to about 34 degrees.
14. The imaging apparatus of claim 9 further comprises a
triangulate calculation mechanism applied to the at least two
captured image frame data from both of the first and the second
camera to determine the spatial location of the sports object at an
instant of flight time corresponding to each flashed
illumination.
15. The imaging apparatus of claim 9 further comprises an image
enhance.ement technique to enhance the contrast and image sharpness
of the sports object image from the captured image frame data for
the processing and analyzing of the captured image frame data.
16. The imaging apparatus of claim 9 wherein said flash device is
triggered with an acoustic, an optical or an electronic device.
17. The imaging apparatus of claim 9 wherein said sports object is
a golf ball and wherein said launch parameters comprise a launch
angle, a launch speed and a launch azimuth in degrees of push or
Pull.
18. The imaging apparatus of claim 17 wherein the surface of said
golf ball further comprises one or two markings whereby, based upon
the location and orientation of the one or two markings contained
in the captured image frame data, the computing device determines
additional sports object launch parameters of back-spin RPM
(revolutions per minute), side-spin RPM and rifle-spin RPM.
19. The imaging apparatus of claim 18 wherein the shape of each of
said markings is a bar or a line.
20. The imaging apparatus of claim 9 wherein each of said at least
a first and a second camera is a digital CMOS or CCD camera.
21. A method of monitoring the early flight of a launched sports
object, the method comprises: (a) emanating at least two flashed
illuminations, separated by a predetermined time interval, at the
sports object thus creating at least two corresponding flight
scenes of the sports object; (b) electronically capturing, near the
launched sports object and under a continuous video mode, image
frame data corresponding to said flight scenes; and (c) acquiring,
processing and analyzing the captured image frame data into sports
object launch parameters.
22. The method of claim 21 wherein the processing and analyzing the
captured image frame data further comprises a step of using an
image frame background subtraction technique to freeze and
recognize the sports object image in flight.
23. The method of claim 22 wherein the processing and analyzing of
the captured image frame data further comprises a step of using an
image enhancement technique to enhance the contrast and image
sharpness of the sports object image from the captured image frame
data.
24. The method of claim 21 wherein said sports object is a golf
ball and wherein said launch parameters comprise a launch angle, a
launch speed and a launch azimuth in degrees of push or Pull.
25. The method of claim 24 further comprises providing the surface
of said golf ball with one or two markings and, based upon the
location and orientation of the one or two markings contained in
the captured image frame data, determining additional sports object
launch parameters of back-spin RPM (revolutions per minute),
side-spin RPM and rifle-spin RPM.
26. The method of claim 21 wherein said electronically capturing of
image frame data further comprises a step of using at least one
digital CMOS or CCD camera located with a predetermined spatial
relationship with a pre-launch position of the sports object.
27. A method of monitoring the early flight of a launched sports
object, the method comprises: (a) emanating at least two flashed
illuminations, separated by a predetermined time interval, at the
sports object thus creating at least two corresponding flight
scenes of the sports object; (b) capturing image frame data
corresponding to said flight scenes with an electronic camera
system located near the launched sports object but spaced from it
by a predetermined distance D.sub.cm transverse to the sports
object launch direction, wherein the camera system further
comprising at least a first and a second camera wherein the second
camera being mounted essentially vertically above and separated
from the first camera by a predetermined distance D.sub.sp thereby
creating a corresponding difference in golf ball viewing angle
.DELTA..theta. between the first camera and the second camera; and
(c) acquiring, processing and analyzing the captured image frame
data into sports object launch parameters.
28. The method of claim 27 further comprises mounting said first
camera near the ground.
29. The method of claim 27 further comprises setting said distance
D.sub.sp to be greater than an equivalent diameter of the sports
object.
30. The method of claim 27 wherein said sports object is a golf
ball having a diameter of about 1.7 inches.
31. The method of claim 30 further comprises setting said distance
D.sub.cm to be within a range from about 12 to about 24 inches and
said distance D.sub.sp to be within a range from about 4 to about 8
inches thereby creating a difference in golf ball viewing angle
.DELTA..theta. between about 9 to about 34 degrees.
32. The method of claim 27 wherein the processing and analyzing of
the captured image frame data further comprises applying
triangulate calculation to the at least two captured image frame
data from both of the first and the second camera and determining
the spatial location of the sports object at an instant of flight
time corresponding to each flashed illumination.
33. The method of claim 27 wherein the processing and analyzing of
the captured image frame data further comprises using an image
enhancement technique and enhancing the contrast and image
sharpness of the sports object image from the captured image frame
data.
34. The method of claim 27 wherein said sports object is a golf
ball and wherein said launch parameters further comprise a launch
angle, a launch speed and a launch azimuth in degrees of push or
Pull.
35. The method of claim 34 further comprises providing the surface
of said golf ball with one or two markings and, based upon the
location and orientation of the one or two markings contained in
the captured image frame data, determining additional sports object
launch parameters of back-spin RPM (revolutions per minute),
side-spin RPM and rifle-spin RPM.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This utility patent application is based upon thus claims
the priority of a provisional application Ser. No. 60/491,886,
filed Aug. 1, 2003, by the same inventor.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to the field of
electronic monitoring of high-speed events. More particularity, the
present invention is directed to a video image acquisition
apparatus for monitoring launch parameters of a launched sports
object such as a flying golf ball.
[0004] 2. Description of the Related Art
[0005] There are a number of apparatus or monitoring systems
available since the 70's to measure high-speed events, in
particular the launch parameters of flying golf balls. However, any
apparatus or systems designed for measuring golf ball launch
parameters will have some inherent limitations as well as optimal
operational specifications. Over the years, high-speed camera
and/or stroboscopic photography technologies have been used by a
number of golf equipment manufacturers in the development process
for golf ball and golf club such as the early invention of U.S.
Pat. No. 4,158,853. As this type of technology has become
increasingly prevalent for the measurement of golf ball launch
parameters, the use of high-speed camera images has become more
available and sophisticated such as described in U.S. Pat. Nos.
5,471,383, 6,241,622, 6,579,190 and 6,592,465.
[0006] However, all these prior arts use similar approaches with
high shutter speed and multi-shuttering camera or cameras to
capture two-dimensional (2-D) fast flying ball images for launch
parameter calculations. These require specialty and expensive high
shutter speed or multi-shuttering camera and cameras to meet the
image capturing requirements. Furthermore, the physical locations
of the balls in space at any given time is not precisely measured
as limited by the camera resolution and image distortion to be
described later. Inherent measurement errors of these 2-D high
speed camera and stroboscopic photography systems fall into two
categories, namely camera hardware limitations (such as camera
pixel resolution, focus, and lens distortion) and dynamic set-up
variables (operator and system setup related variables such as
camera height and distance to ball, camera leveling). As described
herein, these components of measurement error have an
interdependent relationship with one another, meaning that the
accuracy of each parameter depends upon the accuracy of every other
parameter.
[0007] During golf ball launch, a 2-D camera system is often used
to measure ball speed, launch angle, back-spin RPMs (revolutions
per minute), and sometimes azimuth (in degrees of Push or Pull) and
side-spin RPMs. By accurately measuring these parameters,
algorithms shaped by field-testing and calibration can be used to
predict golf ball flight (and roll). The purpose of the camera is
to capture two or more successive images of a high-speed
occurrence--a speeding golf ball moving up to 200 MPH (miles per
hour) with a ball spin of up to 12,000 RPMs and launch angles from
0 to 65 degrees. These images are then processed by image
recognition software or spatial mapping software that calculates
the launch parameters of the shot based upon the movement of
pre-defined markings on the golf ball over a series of images.
[0008] To provide image processing software with meaningful images
to accurately calculate golf ball launch parameters, the
orientation of the camera along the x-, y-, and z-axes spatially,
as well as the side to side and/or up and down position of the
camera lens, for every starting and dynamic ball location, are
critical. Otherwise, parallax views will severely limit the ability
of a camera system to provide representative images of the golf
ball launch parameters (a three-dimensional occurrence), hence
limiting the accuracy of prediction of ball flight and roll with
such systems. A good illustrative example of error from parallax
view is when one tries to measure ball speed with a 2-D camera
positioned at a perpendicular angle to the target line. To better
understand the concept of parallax viewing error, imagine trying to
read the gas gauge of our automobile from the passenger seat. Here,
the fuel gauge does not appear the same way as it does to the
driver whose sitting position faces the fuel gauge straight on.
Trying to measure ball speed with a non-zero azimuth with a camera
system works the same way. FIG. 1 illustrates ball speed
measurement error across positive (PUSH) and negative (PULL)
azimuth angles. As one can see, only when the direction of the ball
5 is 90 degrees to the view angle of the camera 10 as in trajectory
1, will one get reliable and accurate results with little or
minimum error. In general, shots with a (+) azimuth, a PUSH
traveling towards the camera 10 as in trajectory 2, will appear to
have a progressively higher ball speed than the actual, while those
shots with a (-) azimuth, a PULL traveling away from the camera 10
as in trajectory 3, will appear to have a progressively lower ball
speed than the actual. In essence, under the circumstance of FIG.
1, the ball speed measurement calculation is dependent upon the
azimuth angle of the ball 5.
[0009] Non-zero azimuth shots introduce parallax error also into
the launch angle measurements of the camera 10 and this is
demonstrated in FIG. 2. While the camera 10 will see the three
shots depicted in the image as having the same launch angle, the
shot with positive azimuth traveling towards the camera, having a
trajectory 2, will have an actual launch angle lower than the
reported launch angle, while the shot with negative azimuth
traveling away from the camera, having a trajectory 3, will have an
actual launch angle higher than the reported launch angle. In
essence, under the circumstance of FIG. 2, the launch angle
measurement calculation is dependent upon the azimuth angle of the
ball 5 as well. Thus, unless a straight shot of 0 degrees azimuth
is achieved, as signified by trajectory 1 of FIG. 1 and FIG. 2, a
camera system will have the effect of parallax error spill into
both ball speed and launch angle calculations. Furthermore, when
using correction formulas to compensate for the effect of azimuth
errors on other parameters, the azimuth angle itself is often
miscalculated due to difficulty of producing an accurate azimuth
calculation. While some prior art attempts to reconcile the errors
of ball speed and launch angle with an azimuth estimation and
correction formulas based on size variations of the ball image are
presented such as in U.S. Pat. No. 6,579,190, the limitation or
pixel resolution of typically-used high shutter speed cameras
results in an azimuth accuracy limited to +/-3 or 5 degrees, or
equivalently a 6-10 degrees error variance by using single camera
picture with multiple ball sizes or diameters captured with
multiple shutter sequences. The physical diameter of a golf ball,
as compared to the frame size required to capture multiple ball
images in launch condition, limits the resolution to accurately
estimate the ball azimuth angle. Simply put, a wrongful use of the
azimuth correction formula can easily result in a 5+ MPH error in
ball speed and a 3+ degrees error in launch angle. The present
invention successfully provides better and improved solutions to
the camera feature requirements and measurement of actual ball
locations.
SUMMARY OF THE INVENTION
[0010] The present invention relates to video apparatus for
improved monitoring of the launch position, velocity and spins of a
golf ball. By using stroboscopic photography with at least two
flashes at a predetermined interval triggered by either acoustic,
optical or electronic means and a digital CMOS (Complementary
Metal-Oxide-Semiconductor) or CCD (charge coupled device) camera
system, running at a continuous video mode, the present invention
is capable of capturing all needed ball image information for
computer processing, analysis and display of useful data.
Furthermore, according to one embodiment of the present invention,
a dual camera system with at least two cameras spaced out by a
distance greater than the ball diameter and mounted preferably
vertically to the ground is capable of providing much improved
measurement of ball location in three-dimensional space at the
times of the flashes, hence enabling more precise determination of
the ball azimuth angle, ball speed, and launch angle.
[0011] Preferred embodiments of the present invention are presented
including a dual camera system interfaced with a data collecting
computer, flashes with trigger mechanism located at a given
distance to the ball flight trajectory path.
[0012] To the accomplishment of the above and related objects, this
invention may be embodied in the form illustrated in the
accompanying drawings, attention being called to the fact, however,
that the drawings are illustrative only, and that changes may be
made in the specific construction illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Various other objects, features and attendant advantages of
the present invention will become fully appreciated as the same
becomes better understood when considered in conjunction with the
accompanying drawing, in which like reference characters designate
the same or similar parts throughout the several views, and
wherein:
[0014] FIG. 1 illustrates prior art ball speed measurement error
across positive (PUSH) and negative (PULL) azimuth angles;
[0015] FIG. 2 illustrates the parallax error of prior art launch
angle measurements from non-zero azimuth shots;
[0016] FIG. 3 illustrates a preferred embodiment and arrangement of
the present invention wherein a dual camera system interfaced with
a data collecting computer and flashes with triggering mechanism
located at a given distance to a ball flight trajectory path;
[0017] FIG. 4 illustrates two captured flying golf ball images each
with a ball mark in a high speed camera or a stroboscopic
photography system;
[0018] FIG. 5 illustrates two different modes of camera shuttering
design used in a stroboscopic photography system, they are (a)
prior art high shutter speed camera which must synchronize its
timing with the strobe or flash light pulses and (b) the continuous
mode of operation which is independent to strobe or flash light
pulses according to the present invention;
[0019] FIG. 6 shows two ball images captured through the present
invention of digital camera running at continuous video mode
followed by applying image subtraction and enhancement
technique;
[0020] FIG. 7 illustrates an improved way of measuring the ball
azimuth position with a dual camera system of the present
invention;
[0021] FIG. 8 shows ball images obtained from the dual camera
system of the present invention, they are (a) ball image captured
from the top camera and (b) ball image captured from the bottom
camera;
[0022] FIG. 9 illustrates a preferred camera arrangement of the
present invention with vertical mounting; and
[0023] FIG. 10 illustrates a horizontal camera mounting with
associated creation of undesirable shift in the ball images.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] In the following detailed description of the present
invention, numerous specific details are set forth in order to
provide a thorough understanding of the present invention. However,
it will become obvious to those skilled in the art that the present
invention may be practiced without these specific details. In other
instances, well-known methods, procedures, materials, components
and circuitry have not been described in detail to avoid
unnecessary obscuring aspects of the present invention. The
detailed description is presented largely in terms of simplified
orthogonal and perspective views. These descriptions and
representations are the means used by those experienced or skilled
in the art to concisely and most effectively convey the substance
of their work to others skilled in the art.
[0025] Reference herein to "one embodiment" or an "embodiment"
means that a particular feature, structure, or characteristics
described in connection with the embodiment can be included in at
least one embodiment of the invention. The appearances of the
phrase "in one embodiment" in various places in the specification
are not necessarily all referring to the same embodiment, nor are
separate or alternative embodiments mutually exclusive of other
embodiments. Further, the order of process flow representing one or
more embodiments of the invention do not inherently indicate any
particular order nor imply any limitations of the invention.
[0026] FIG. 3 illustrates a preferred embodiment and arrangement of
the present invention wherein a dual camera system, including
camera A 26 and camera B 28, interfaced with a data collecting
computer 30 and a flash light 24 with a flash light trigger 22
located at a given distance to a ball flight trajectory 18. The
data collecting computer 30 has a computer display 32 for
displaying information. Two ball images 14 and 16 that reflect the
stroboscopic images, created by two flashes emitted by the flash
light 24 after triggering by the flash light trigger 22, are
referenced to the tee 20 location through a ball flight trajectory
18.
[0027] FIG. 4 illustrates two captured and displayed flying golf
ball images 40 and 42 respectively with ball marks 40a and 42a in a
typical high shutter speed camera or a stroboscopic photography
system. Numerous ball flight parameters are calculated according to
these ball images 40 and 42 immediately after launch. The ball
marks 40a and 42a are of the shape of a bar or line and these are
typically used in the art to provide back, side and rifle spins
information. Distance d between the two ball images 40 and 42 is
used to calculate the ball speed and the launch angle 37 is
determined by the angle between ground 36 and ball flight
trajectory 38 at the tee 20 location. As illustrated earlier, the
actual ball speed and launch angle are highly dependent upon the
exact ball location in three-dimensional space. Thus, accurate
determination of the ball locations from the camera images becomes
vitally important to extract meaningful and accurate ball flight
data hence predicting ball flight trajectory and ball landing
distance satisfactorily.
[0028] FIG. 5 illustrates two different modes of camera shuttering
design used in a stroboscopic photography system. Typical camera
designs in stroboscopic photography use high shutter speed or
multiple-shuttering which opens and closes successively in
synchrony with the flashes or strobe lights and this is illustrated
in FIG. 5(a) where the camera shutter is open when the flashlight
is on and close when the flashlight is off. As the conditions of
ball launch require the time interval between flashes to be very
short, in the range of a couple of milliseconds, the camera shutter
speed or image capturing speed need to be correspondingly fast and
more often to be specially designed or customized at a much higher
camera cost. The present invention, on the other hand, bypasses the
use of multi-shuttering or high shutter speed camera design and,
instead, uses a digital camera under a continuous video mode at a
low frame rate and this is depicted in FIG. 5(b). Thus, under the
present invention the shutter and frame speeds of the camera become
irrelevant. Additionally, by using digital frame background
subtraction and freezing and recognizing the ball images, one can
achieve the same result by using almost any type of digital cameras
hence drastically reducing the camera feature requirements and
lowering the camera cost. FIG. 6 shows two typical ball images 44
and 46 captured through a continuous video mode followed by
applying image subtraction and enhancement technique.
[0029] FIG. 7 illustrates an improved way of measuring the ball
azimuth position with a dual camera system, having a camera A 26
and a camera B 28, of the present invention. With the orientation
of FIG. 7, the ball azimuth position means the left and right
position of the golf ball. In the case of a prior art such as U.S.
Pat. No. 6,579,190, a single camera 50 is used to capture ball size
images. A comparison of the ball size (i.e., the ball diameter bd)
is then applied to determine the displacement of ball in the
azimuth direction (i.e., PUSH or PULL), distance daz. As the ball
diameter bd is relatively small, about 1.68 inches, the azimuth
displacement daz does not create a significant difference of the
camera viewing angle and this is denoted as Angle 1. Hence such a
small viewing angle difference results in a low resolution of the
determination of azimuth angle. However, in the case of the current
invention as illustrated in the lower part of FIG. 7, the same
azimuth displacement daz in our vertically spaced dual camera
system, with an inter-camera distance dc greater than the ball
diameter bd, creates a much more significant difference of the
camera viewing angle Angle 2 and this in turn provides a much
higher resolution of the determination of azimuth angle hence
increasing the measurement accuracy of all major ball launch
parameters such as the ball speed and launch angle. Furthermore, no
ball marking is required here as the ball position is determined by
using the geometric center of the ball image and this provides a
solid reference and better defined image boundary in determining
the actual ball location regardless of any variations in the
viewing angle or the distance and the current invention is much
less sensitive to variations in the external lighting condition,
focusing and blurring commonly associated with the round edges of
the ball. This is very different from both the single camera
approach used in U.S. Pat. No. 6,579,190 and the horizontally
mounted dual camera approach used in U.S. Pat. No. 5,471,383 where
multiple and patterned reflective dots specially marked on the ball
are used.
[0030] FIG. 8 shows some typical ball images obtained from the dual
camera system of the present invention. FIG. 8(a) shows the ball
images captured with camera A 26 while FIG. 8(b) shows strobe or
flash light illuminated ball images captured with camera B 28.
Notice that the X-axis locations of the ball images are relatively
the same in both pictures.
[0031] FIG. 9 further illustrates a preferred camera arrangement of
the present invention with vertically mounted camera A 26 and
camera B 28. As illustrated, the two camera images obtained from
the vertically mounted dual camera system present another
significant improvement in that one can visualize that the ball
horizontal positions (i.e., along the X-axis direction) between the
two cameras are relatively the same in reference to the edges of
the picture. This is so as the view angles of the two cameras are
aligned along the X-axis and the difference in their view angles
mainly appears along the Y-axis. Thus, this vertical arrangement of
the two cameras 26 and 28 is important as the locations of the
first ball image 14 and the second ball image 16 are sensitive to
the ball speed and launch angle for typical low angle golf shots
from drivers and low irons (e.g., in a range from a few degrees to
may be 20 degrees).
[0032] On the other hand, a horizontal camera mounting of camera A
56 and camera B 58 creates unnecessary shift in the ball images and
this is illustrated in FIG. 10. Specifically, the ball image
locations along the X-direction are highly sensitive to the viewing
angles of the cameras 56 and 58 and, which are also dependent on
the ball speed where its X-axis speed component is much higher than
its Y-axis component for typical ball launch conditions of low
angle shots (e.g., from drivers or low irons). As a result,
complicated viewing angle and special corrections become necessary
when the corresponding ball image locations are separated too far
apart along the X-axis as illustrated in FIG. 10. Hence the
horizontal camera mounting of the dual camera system is less
preferred due to its associated problem of X-axis ball image
separation.
[0033] Actual field and calibration test have been conducted to
validate the effectiveness of the current invention and a brief
summary of such tests is listed in Table 1 that demonstrates the
effectiveness and usefulness of the current invention.
1TABLE 1 Actual Field Test Data With Current Invention Actual
Estimated GA CAM Results Carry Carry Ball Launch Back- Side File
Dis- Off- Short Dis- Off- Short Azi- Speed Angle spin spin Name
tance line Shape tance line Shape muth (rph) (deg) (rpm) (rpm)
Drivers BRFast02 245 -5 0 251 7 0.5 -4 160 11.1 3172 625 BRFast03
230 30 3 253 12 0.5 -4 163 10.5 3355 779 BRTM01 225 30 2 244 20 0 4
147 12.6 1812 83 BRTM02 235 5 1 246 12 0 3 149 13.6 1629 18 BRTM03
230 -30 -1.5 238 -33 -0.5 -6 150 10.7 1098 -276 BRHook02 185 -50 -2
191 -52 -2.5 -6 157 11.3 3307 -1448 BRHook03 240 -25 -1 195 -17
-1.5 5 156 10.5 2508 -1492 BRSlice01 250 15 1 260 15 1 -6 159 8.5
1689 1035 BRSlice02 235 25 1.5 224 38 1.5 1 141 12.9 2325 1088
BRSlice03 235 25 1.5 245 13 1 -2 148 14 1985 595 6-iron 6iTM01 160
15 0.5 150 -1 0 -1 110 15.3 6092 86 6iTM02 165 -10 -0.5 162 -4 -0.5
3 117 15.7 6607 -580 6iHookTM01 160 -30 -3 138 -30 -0.5 -7 111 14.1
6480 -878 6iHookTM02 165 -20 -2 156 -10 -0.5 0 112 15.6 5339 -494
6iSliceTM01 155 10 1.5 150 9 0.5 2 113 16.2 7480 257 6iSliceTM02
160 2 0 144 -36 -0.5 -12 106 15.5 6722 -431 Sand Wedge SW01 105 -5
0 102 16 0.5 14 82 35.7 3581 -828 SW02 100 -5 0 97 -11 -1.5 0 77
33.4 2767 -1380 SW03 100 0 0 91 -11 -1 -1 80 36 3160 -1172 SW04 80
5 0 89 5 0 5 76 38.4 4216 -225 SW05 100 0 0 101 -6 -0.5 1 82 36
2326 -717
[0034] For example, with a driver of BRFast02, an Actual Estimated
(current invention) Carry Distance of 245 is obtained versus a
reference from GA CAM Results of 251. For a second example, with a
6-iron of 6iSliceTM01, an Actual Estimated (current invention)
Carry Distance of 150 is obtained versus a reference from GA CAM
Results of 155.
[0035] A video apparatus for improved monitoring of various launch
parameters for a golf ball is described. Using an exemplary
embodiment of stroboscopic photography with at least two
consecutively triggered strobes or flashes and a digital camera
system running at a continuous video mode, the present invention is
capable of capturing all needed ball image information for
processing, analysis and display of useful data. Furthermore,
another embodiment of vertically arranged dual camera system with
at least two cameras is also described for providing improved
measurement of ball location in three-dimensional space at the
times of the flashes. However, for those skilled in this field,
these exemplary embodiments can be easily adapted and modified to
suit additional applications without departing from the spirit and
scope of this invention. Thus, it is to be understood that the
scope of the invention is not limited to the disclosed embodiments.
On the contrary, it is intended to cover various modifications and
similar arrangements based upon the same operating principle. The
scope of the claims, therefore, should be accorded the broadest
interpretations so as to encompass all such modifications and
similar arrangements.
* * * * *