WO2000032281A1

WO2000032281A1 - Sports trainer and simulator

Info

Publication number: WO2000032281A1
Application number: PCT/US1998/025693
Authority: WO
Inventors: Reza Miremadi
Original assignee: Interactive Light, Inc.
Priority date: 1998-12-03
Filing date: 1998-12-03
Publication date: 2000-06-08

Abstract

An apparatus (fig. 3) for determining flight parameters of a ball (10) in flight along a flight path, includes a pair of light conditioning elements (14, 16) on the ball, a first set of sensors (32, 34) having mutually orthogonal fields of view intersecting along a first plane through which the ball initially passes during flight and a second set of sensors (36, 38) having mutually orthogonal fields of view intersecting along a second plane through which the ball subsequently passes during flight. Each sensor includes a linear array of photodiodes for obtaining a linear image of a linear section of the ball. A controller successively pulses the sensors at microsecond intervals to obtain first and second reconstructed images of the entire ball and the locations of the elements thereon at the first and second planes, respectively, and processes changes in the locations of the elements at the first and second planes to derive the flight parameters.

Description

SPORTS TRAINER AND SIMULATOR

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

This invention generally relates to determining the flight parameters

of a flying object such as a golf ball, tennis ball or baseball and, more

particularly, to a sports trainer and simulator for indoor simulation of an athletic

activity with real time presentation and display of the simulated activity,

especially for entertainment purposes.

DESCRIPTION OF THE RELATED ART

Players interested in improving or enjoying their performance in an

athletic activity use indoor simulators for collecting data, such as the flight

parameters of a flying object, and for processing and displaying the processed

data on a visual display that simulates, among other things, the flight of the

object, especially from the viewpoint of the player.

The field of sports simulation, especially golf, is exemplified by the

following U.S. Patents:2,102,166; 3,072,410; 4, 136,387; 4,160,942; 5,160,839;

5,333,874; 5,413,345; 5,479,008; 5,481,355; 5,501,463; 5,575,719; 5,614,942;

and 5,626,526. As advantageous as some of these sports simulators are in improving

the performance and enjoyment of a player, experience has shown that a more

realistic and more accurate simulation is needed. Delays and inaccuracies in

collecting and processing the flight parameter data contribute to increased player

frustration and erroneous data determination.

SUMMARY OF THE INVENTION

OBJECTS OF THE INVENTION

Accordingly, it is a general object of this invention to overcome the

drawbacks of prior art sports trainers and simulators.

More particularly, it is an object of the present invention to reliably

and accurately determine flight parameters of a sports object in flight.

Still another object of the present invention is to dynamically collect,

process and display processed flight parameters on a real-time basis.

It is yet another object of the present invention to provide an

entertaining sports simulator that can be played indoors.

A still further object of the present invention is to provide a sports

simulator requiring a minimum number of sensors to minimize system complexity

and cost. A concomitant object of the present invention is so to provide a

sports simulator which is easy to use and cost-effective in manufacture.

FEATURES OF THE INVENTION

In keeping with these objects and others which will become apparent

hereinafter, one feature of this invention generally relates to an apparatus for

determining flight parameters of a ball in flight along a flight path, especially a

golf trainer and simulator, comprising a pair of light conditioning elements, for

example, reflectors, spaced apart on an exterior surface of the ball, preferably

angularly offset by an angle of about 90°.

A first set and a second set of emitter-detector pairs are arranged

along the flight path, especially right after the launch point of the ball. Each pair

includes an emitter for emitting light, especially infra-red light, as a beam into

space, and a detector adjacent the emitter and having a field of view for detecting

light of variable intensity reflected from the ball, and for generating an electrical

signal whose magnitude is indicative of the detected light intensity. Preferably,

each detector is a linear array of photodiodes or charge-coupled devices (CCD)

for obtaining an image of a section of the ball.

The first set includes a first emitter-detector pair preferably

extending along a horizontal direction and facing upwardly to view a lower surface of the ball, and a second emitter-detector pair preferably extending along

a vertical direction and facing sideways to view a side surface of the ball. The

fields of view of the detectors of the first and second pairs of the first set are

preferably mutually orthogonal and intersect along a first plane through which the

ball initially passes during flight.

The second set includes a third emitter-detector pair preferably

extending along a horizontal direction and facing upwardly to view the lower

surface of the ball, and a fourth emitter-detector pair preferably extending along

a vertical direction and facing sideways to view the side surface of the ball. The

fields of view of the detectors of the third and fourth pairs of the second set are

preferably mutually orthogonal and intersect along a second plane through which

the ball subsequently passes during flight. The second plane is downstream of the

first plane as considered along the flight path.

A controller, preferably a programmed microprocessor, is operative

for controlling the detectors of each set when the ball passes through the first and

second planes to obtain multiple, successive images of successive sections of the

ball, and for reconstructing an entire image of the ball from the images of the

successive sections. At least one reconstructed image, and preferably a plurality

of reconstructed images, of the ball depicts the ball and the location of at least

one of the reflectors thereon. The change in the locations of the reflectors is used to ascertain the spin of the ball. Other flight parameters, such as the speed and

the, launch angle of the ball are determined from the data collected by the

detectors.

In the preferred embodiment, the microprocessor pulses the detectors

at rapid intervals on the order of ten microseconds so that the number of multiple,

successive images in each of the first and second planes is sufficient to map the

entire surface of the ball that faces the detectors. At least five and more such

images, preferably linear, are combined to form the reconstructed image of the

entire ball surface. The use of partial images helps to resist the degrading effects

of ambient noise from the environment, and promotes the accurate and reliable

determination of the flight parameters.

The novel features which are considered as characteristic of the

invention are set forth in particular in the appended claims. The invention itself,

however, both as to its construction and its method of operation, together with

additional objects and advantages thereof, will be best understood from the

following description of specific embodiments when read in connection with the

accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWTNGS

FIG. 1 is a schematic perspective view of a golf simulator according

to this invention; FIG. 2 is a schematic representation of a sensor used in the simulator

of FIG. 1;

FIG. 3 is an electrical circuit diagram of an electro-optical controller

circuit used in the simulator of FIG. 1;

FIG. 4a and FIG. 4b are representative images of side and bottom

views of a golf ball at a first plane;

FIG. 5a and FIG. 5b are representative images of side and bottom

views of a golf ball at a second plane;

FIG. 6 is a three-dimensional plot of reflected light intensity versus

time and versus position of a representative image of FIGS. 4a, 4b, 5a or 5b;

FIG. 7a and FIG. 7b are schematic views of a detail of FIG. 3,

illustrating how distance of a golf ball relative to a sensor is determined; and

FIGS. 8a, 8b, 8c and 8d are representative images of the golf ball

and an optically enhanced spot thereon, illustrating how direction and rate of spin

of the golf ball are determined from the position and distortion of the spot image.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, a golf ball 10 seated on a tee 12 is otherwise

conventional, except for a pair of optically enhanced spots 14, 16 spaced apart

from one another, preferably angularly offset by 90° . Each spot has an optical reflectivity different from that of the ball itself. Preferably, each spot is

constituted of a reflective, or retroreflective, material, but could equally well be

constituted of a light absorbing material. Each spot can be a dot adhesively

secured to the ball, or can be a colored region on the ball. These spots are used,

as explained below, to determine the position of a respective spot at different

points of time. Although not preferred, it is contemplated that the golf ball

dimples themselves may have a sufficient contrasting optical reflectivity from the

exterior ball surface to be adequate indicators of the orientation of the ball at a

given time.

A representative electro-optical sensor, as depicted in FIG. 2,

includes a light emitter 18 for emitting light, preferably infrared, as a shaped

beam 20, and a light detector 22 for detecting light over a field of view 24.

Optical elements, including a lens 26 and a linear slit aperture 28 depicted in

FIG. 3, are positioned in front of the detector 22 so that the field of view

occupies a generally planar region of space. The intersection of the generally

planar field of view 24 and the shaped beam 20 is indicated in FIG. 2 by the

reference numeral 30, and is likewise planar.

Returning to FIG. 1, a first side sensor 32 is mounted above the

ground and its field of view faces a side elevation of the ball. A first bottom

sensor 34 is mounted on the ground and its field of view faces upwardly toward a bottom of the ball. The intersecting fields of view of the first side and bottom

sensors define a generally planar first plane 40 that is situated a predetermined

distance, on the order of a few inches, downstream of the ball after the latter has

been struck by a golfer.

A second side sensor 36, identical to side sensor 32, and a second

bottom sensor 38, identical to bottom sensor 34, are oriented so that their

intersecting fields of view define a generally planar second plane 42 that is

situated a given distance, again on the order of a few inches, downstream of the

first plane. As indicated by the arrow 44, the ball 10 passes sequentially through

the first and second planes 40, 42.

As the ball passes through each plane, an image of the ball, together

with an image indicating the presence or absence of one or both of the spots 14,

16 is taken in order to determine various flight parameters of the ball as described

below. Specifically, the image at each plane is reconstructed from multiple

images of partial sections of the ball. The change in position of the spots of the

reconstructed images between the first and second planes is used to determine

whether the ball is experiencing a side spin and/or back spin.

Returning to FIG. 3, the detector of each sensor 32, 34, 36, 38 is a

linear array 46 of infrared photodiodes and, as shown, twelve, in number. Each

photodiode is connected to an amplifier 48 (only two shown for simplicity) for amplifying an electrical analog signal generated by each photodiode with an

amplitude proportional to the intensity of light detected by the respective

photodiode. The output of each amplifier is connected to individual sample-and-

hold circuits 50, low pass filters 52 and analog-to-digital converters 54 prior to

being input to a programmed microprocessor or controller 56. The converters

54 are also connected to a 4 to 16 bit converter 58, a static-RAM device 60 and

a binary counter 62.

The controller has several outputs: one is connected to a local bus

interface 64 which in turn is connected to other circuit boards; another is

connected to non-volatile RAM 66; and still another is connected via a RS 232

converter 68 to a computer for further processing and display. Another

controller output is connected to a digital-to-analog converter 70 and a pair of

buffers 72, 74 and, in turn, to a pair of voltage-to-current converters 76, 78

which, in turn, are connected to the emitters 80, 82 of the sensors 32, 34 at the

first plane and to the emitters 84, 86 of the sensors 36, 38 at the second plane.

In operation, the controller generates output signals and energizes the

emitters 80, 82, 84, 86 of the sensors 32, 34, 36, 38, preferably by pulsing these

emitters at rapid time intervals on the order of tens of microseconds. After the

ball is struck, the ball initially passes through the first plane 40 created by the

detectors 46 of side and bottom sensors 32, 34. The controller energizes these detectors, preferably by pulsing them at rapid time intervals, again on the order

of microseconds, e.g., 10 microseconds.

Each sensor acts as a line scanner and, due to the rapid pulsing of

each detector, multiple linear images are generated by respective detectors as the

ball passes through the first plane. As shown in FIG. 4a, each photodiode of the

side sensor 32 detects the intensity of the light reflected off the ball, one line at

a time, at 10 microsecond intervals apart. Individual columns 1-9 and rows a-g

are illustrated. In columns 1 and 9, only one photodiode registered reflected

light. In columns 4, 5 and 6, seven photodiodes registered reflected light. At

column 5, row d, a photodiode registered a different amount of light as compared

to its neighboring photodiodes, thus indicating the presence of a spot 14 or 16 on

the ball. FIG. 4a thus shows the outline of the side of the ball and the presence

of a spot, all as seen from side sensor 32.

FIG. 4b is analogous to FIG. 4a, and shows the bottom view of the

ball at the first plane as seen from the bottom sensor 34.

FIG. 5a is analogous to FIG. 4a, and shows the side view of the ball

at the second plane as seen from the side sensor 36.

FIG. 5b is analogous to FIG. 4b, and shows the bottom view of the

ball at the second plane as seen from the bottom sensor 38. During passage between the first and second planes, the ball may

experience side spin and/or back spin as indicated in FIG. 1 by the arrows 88,

90. Back spin will cause a shift in the position of spot 14. Side spin will cause

a shift in the position of spot 16. A comparison of FIGS. 4a and 5a reveals no

shift in the position of spot 16; hence, the ball experienced no side spin. A

comparison of FIGS. 4b and 5b reveals a shift in the position of spot 14; hence,

the ball experienced a back spin whose magnitude is proportional to the amount

of the shift.

Each photodiode generates an analog electrical signal having a

variable range of amplitudes, thereby permitting the general image of the ball to

be differentiated from each spot. These signals are amplified by the amplifiers

48 and fed to the sample-and-hold circuits 50 which capture the amplitudes of the

reflected light. The sampling time is governed by the controller 56. The

sampled voltage is filtered by low pass filters 52 before being digitized by the

converters 54. The digitized waveform of the reflected light is then stored

directly into the static-RAM 60, whose timing is controlled by the counter 62 and

the controller 56.

As shown in FIG. 3, the outputs of the low pass filters are also

conducted to, and summed by, a summing amplifier 92 and then conducted to one

input of a comparator 94 whose other input receives a reference voltage generated by a digital-to-analog converter 96 and the controller 56. This circuitry allows

real time capture of the ball passing through the first or second planes. Since all

the outputs of the filters are summed, the passage of the ball through a respective

plane will trip the comparator 4, thereby signaling the controller 56 to start

capturing data.

Once the ball has left the first and/or second planes, the data stored

in the static RAM 60 is processed by the controller to determine such flight

parameters as ball speed, launch angle, side angle, back spin and side spin.

FIG. 6 is a three-dimensional plot of reflected light intensity or

energy, versus time (expressed in microseconds) and versus position (expressed

in columns) of a representative one of the above captured images of FIGS. 4a,

4b, 5a or 5b. The rounded base represents energy from the surface of the ball.

The peak in the center is the energy from a spot placed on the ball. The

algorithm to obtain all measurements requires eight parameters from the four

images. These parameters for the representative image of FIG. 6 include the

center of the rounded base ("CenterBall") and the center of the peak of the spot

("CenterReflector"), both of which are functions of time and column.

CenterBall is obtained by slicing a portion of the base horizontally

right above the noise floor and finding the center of mass for that portion.

CenterReflector is found similarly by slicing a portion of the peak horizontally and finding the center of mass. The equations for calculating these parameters

are:

Equation (1):

∑_Q columnX-value CenterBall _Column = —

Equation (2):

Υ timeX-value

CenterBall _Tme-

∑₀ value

where "value" is the energy at a certain time and column position. Variable "n"

goes through every row and column position.

Once the CenterBall and CenterReflector are known for the bottom

sensors, the side angle, velocity and back spin can be calculated. Similarly, once

the CenterBall and CenterReflector are known for the side sensors, the launch

angle, velocity and side spin can be calculated. The equations for the launch and

side angles are:

Equation (3):

_τ , . , Arctan(ColSideSensor2-ColSideSensorl)

LaunchAngle - -

TrapDistance

Equation (4):

„. , . , _ Arctan(ColBottonSensor2 -ColBottomSensor 1)

TrapDistance where the trap distance is the distance between the two side or bottom sensors;

where bottom sensors 1 and 2 correspond to sensors 34, 38; and where side

sensors 1 and 2 correspond to sensors 32, 36.

Once the launch and side angles are known, the true velocity (v) of

the ball can be calculated by:

Equation (5):

A =ColSideSensor2 -ColSideSensorl Equation (6): B =ColBottomSensor2 -ColBottomSensor 1 Equation (7):

_ s (A)²+(B)²+(TrapDistance)² TimeSensor2 - TimeSensorl

To obtain spin, the algorithm needs four values from side sensors for

side spin and four values from the bottom sensors for back spin. The four values

are the ball and reflector positions for the two planes. Once these values are

known, they can be plugged into the following equations and solved

simultaneously to determine spin.

Equation ( ^v8) ': X _v=vt ,l₇ +r-cos( _tspi .n-6 ,-t_{t l} π . )

180

Equation (9):

71

X+ TrapDistance =v(t2) +rcos(spin-6-t2 )

Where X is the distance the ball travels (unknown), v is the velocity

of the ball, tl is the time the ball arrives at the first plane, r is the radius of the

golf ball, spin is the spin in revolutions per minute (unknown), t2 is the time the ball arrives at the second plane, and TrapDistance is the spacing between the first

plane and the second plane.

The parameters thus determined are processed by a computer which,

in turn, is connected to a video projector or a monitor, each of which is operative

for displaying a series of video images depicting the trajectory of the ball. The

arrangement of this invention finds particular utility as an entertainment vehicle

in indoor arcades and sports facilities, and as a training vehicle for providing

sports enthusiasts with realistic game play.

As described so far, the first set of emitter-detector pairs has two

fields of view that intersect at the first plane, and similarly, the second set of

emitter-detector pairs has two fields of view that intersect at the second plane.

Certain flight parameters can be determined without requiring two intersecting

fields of view at each plane.

For example, the distance of the ball relative to a sensor can be

determined with a single field of view by looking at how big or small the ball

appears to the sensor. Thus, in FIG. 7a, the ball 10 is closer to the photodiode

array or sensor 46 as compared to FIG. 7b. The closer the ball 10 is to the

sensor, the more cells of the array 46 detect the golf ball image. By way of

example, eight cells of the array 46 in FIG. 7a detect light, whereas only four

cells of the array 46 detect light in FIG. 7b. The distance of the ball from the array can thus be determined by examining how many cells of the array 46 have

detected light. In a preferred embodiment, a golf ball about one inch from the

array will be detected by all twelve cells, whereas a golf ball about twelve inches

from the array will be detected by about one cell.

The direction and rate of ball spin can also be determined by a single

field of view. In FIGS. 8a, b, c, d, the image of the ball 10 is indicated by the

elliptical area 10', and the images of a representative element or spot 14 are

indicated by spot zones 14a, b, c and d, respectively.

The position and shape of the spot zones are employed to determine

flight parameters. FIG. 8a shows the image of the spot zone 14a centrally located

within the image of the ball 10, thereby indicating that the ball is not spinning.

FIG. 8b shows the image of the spot zone 14b displaced toward the right as

compared to spot zone 14a, thereby indicating that the ball is spinning in one

direction. FIG. 8c shows the image of the spot zone more elliptical, i.e., wider

along the horizontal direction along which time is measured. This indicates that

the spot is in the field of view of the sensor for a longer time as compared to

FIG. 8b. The longer the width or "distortion" of the spot zone 14c, the faster the

spin. FIG. 8d shows that the image of the spot zone 14d is displaced toward the

left, thereby indicating that the ball is spinning in the opposite direction compared

to FIGS. 8b or 8c. Also, the narrower width of the spot zone 14d along the

horizontal direction indicates that the ball is spinning at a slower rate as compared to FIGS. 8b or 8c. Thus, the direction and rate of spin can be determined from

the displacement and size of the spot zone.

An emitter-detector pair such as 32 or 36 in FIG. 1 can be used to

determine side spin and, if the known starting point of the ball is factored in, then

the side angle of the ball can also be determined. An emitter-detector pair such

as 34 or 38 in FIG. 1 can be used to determine back spin and, since the starting

point is known, the launch angle of the ball can also be determined. By

measuring how long a ball takes to move through a known field of view and at

a known side and launch angle, the velocity of the ball can be measured.

Thus, only two emitter-detector pairs, e.g., 32 and 34, are needed

to measure spin, velocity and angle. Additional emitter-detector pairs, e.g., 36

and 38 are used to improve resolution.

It will be understood that each of the elements described above, or

two or more together, also may find a useful application in other types of

constructions differing from the types described above.

While the invention has been illustrated and described as embodied

in a sports trainer and simulator, it is not intended to be limited to the details

shown, since various modifications and structural changes may be made without

departing in any way from the spirit of the present invention. Thus, the present invention can be used to determine the flight

parameters of other objects, such as a baseball or a tennis ball. The object need

not be associated with a sport, but could equally well be associated with another

non-athletic activity.

Without further analysis, the foregoing will so fully reveal the gist

of the present invention that others can, by applying current knowledge, readily

adapt it for various applications without omitting features that, from the

standpoint of prior art, fairly constitute essential characteristics of the generic or

specific aspects of this invention and, therefore, such adaptations should and are

intended to be comprehended within the meaning and range of equivalence of the

following claims.

What is claimed as new and desired to be protected by Letters Patent

is set forth in the appended claims.

Claims

I CLAIM:

1. An apparatus for determining flight parameters of a ball in

flight along a flight path, comprising:

a) a pair of light conditioning elements spaced apart on an

exterior surface of the ball;

b) a first set of emitter-detector pairs having fields of view

intersecting along a first plane through which the ball passes during flight;

c) a second set of emitter-detector pairs having fields of

view intersecting along a second plane through which the ball passes during

flight, said second plane being spaced downstream of the first plane along the

flight path;

d) each emitter-detector pair of the first and second sets

having an emitter for emitting light in a respective one of said planes to the ball

for reflection from the ball, and a detector adjacent the respective emitter for

detecting light of variable intensity reflected from the ball to generate electrical

signals indicative of the detected light intensity, each detector including an array

of sensors for obtaining an image of a section of the ball, one of the electrical

signals having a peak amplitude corresponding to a location of at least one

element on the ball; and e) a controller for controlling the detectors of each set

when the ball passes through the respective planes to obtain multiple, successive

images of successive sections of the ball to obtain first and second reconstructed

images of the entire ball and the locations of the elements thereon at said first and

second planes, respectively, and for processing changes in the locations of the

elements at said first and second planes to derive the flight parameters.

2. The apparatus as defined in claim 1, wherein the elements

have light-reflecting properties, and wherein the peak amplitude of the electrical

signal corresponds to a maximum amplitude of the electrical signal.

3. The apparatus as defined in claim 2, wherein the elements

subtend an angle on the order of 90° .

4. The apparatus as defined in claim 1, wherein each emitter is

an infra-red diode, and wherein each array is a row of charge-coupled

photodiodes, and wherein each detector includes a focusing lens and a linear

aperture located adjacent the photodiodes and extending lengthwise of the row.

5. The apparatus as defined in claim 1, wherein one of the

emitter-detector pairs of each set extends along a vertical direction, and wherein

the other of the emitter-detector pairs of each set extends along a horizontal

direction.

6. The apparatus as defined in claim 5, wherein the field of view

of said one of the pairs faces a side elevation view of the ball, and wherein the

field of view of said other of the pairs faces a bottom plan view of the ball.

7. The apparatus as defined in claim 1 , wherein the fields of view

of the first set of emitter-detector pairs are mutually orthogonal.

8. The apparatus as defined in claim 1 , wherein the fields of view

of the second set of emitter-detector pairs are mutually orthogonal.

9. The apparatus as defined in claim 1, wherein the array of

sensors of each detector is arranged along a linear row for obtaining a linear

image of a linear section of the ball.

10. The apparatus as defined in claim 1, wherein the controller is

operative for successively pulsing the detectors of each set at microsecond

intervals.

11. The apparatus as defined in claim 10, wherein the microsecond

intervals are on the order of less than ten microseconds in duration.

12. The apparatus as defined in claim 10, wherein the controller

is operative for reconstructing each reconstructed image only after all detectors

of each set have been pulsed including, for each sensor, a sample-and-hold circuit

for sampling and holding the electrical signal from a respective sensor; a low pass

filter having an output and operative for filtering the sampled and held signal; a summing amplifier for summing the filtered signal; and a comparator having a

first input for receiving the output of each low pass filter, a second input for

receiving a reference signal, and an output connected to the controller for

signaling the controller to begin image reconstruction.

13. A golf simulator for determining flight parameters of a golf

ball in flight along a flight path, comprising:

a) a pair of light reflecting elements spaced apart on an

exterior surface of the ball;

b) a first set of emitter-detector pairs having fields of view

intersecting along a first plane through which the ball passes during flight;

c) a second set of emitter-detector pairs having fields of

view intersecting along a second plane through which the ball passes during

flight, said second plane being spaced downstream of the first plane along the

flight path;

d) each emitter-detector pair of the first and second sets

of sensors for obtaining an image of a section of the ball, one of the electrical signals having a maximum amplitude corresponding to a location of said at least

one element on the ball; and

e) a controller for successively pulsing the detectors of

each set when the ball passes through the respective planes at microsecond

intervals to obtain multiple, successive linear images of successive linear sections

of the ball to obtain first and second reconstructed images of the entire ball and

the locations of the elements thereon at said first and second planes, respectively,

and for processing changes in the locations of the elements at said first and

second planes to derive the flight parameters.

14. The simulator as defined in claim 13, wherein the light

reflecting elements are adhesively secured to the ball.

15. The simulator as defined in claim 14, wherein the elements

subtend an angle on the order of 90° .

16. The simulator as defined in claim 13, wherein each emitter is

an infra-red diode, and wherein each array is a row of charge-coupled

photodiodes, and wherein each detector includes a focusing lens and a linear

aperture located adjacent the photodiodes and extending lengthwise of the row.

17. The simulator as defined in claim 13, wherein one of the

emitter-detector pairs of each set extends along a vertical direction, and wherein the other of the emitter-detector pairs of each set extends along a horizontal

direction.

18. The simulator as defined in claim 17, wherein the field of view

field of view of said other of the pairs faces a bottom plan view of the ball.

19. The simulator as defined in claim 13, wherein the fields of

view of the first set of emitter-detector pairs are mutually orthogonal.

20. The simulator as defined in claim 13, wherein the fields of

view of the second set of emitter-detector pairs are mutually orthogonal.

21. The simulator as defined in claim 13, wherein the array of

sensors of each detector is arranged along a linear row for obtaining a linear

image of a linear section of the ball.

22. The simulator as defined in claim 13, wherein the controller

is operative for successively pulsing the detectors of each set at microsecond

intervals.

23. The simulator as defined in claim 22, wherein the microsecond

intervals are on the order of less than ten microseconds in duration.

24. The simulator as defined in claim 22, wherein the controller

of each set have been pulsed including, for each sensor, a sample-and-hold circuit for sampling and holding the electrical signal from a respective sensor; a low pass

filter having an output and operative for filtering the sampled and held signal; a

summing amplifier for summing the filtered signal; and a comparator having a

receiving a reference signal, and an output connected to the controller for

signaling the controller to begin image reconstruction.

25. An apparatus for determining flight parameters of a ball in

flight along a flight path, comprising:

a) a light conditioning element on an exterior surface of the

ball;

b) a first emitter-detector pair having a field of view

through which the ball passes during flight;

c) a second emitter-detector pair having a field of view

through which the ball passes during flight;

d) each emitter-detector pair having an emitter for emitting

light to the ball and the element for reflection therefrom, and a detector adjacent

the respective emitter for detecting light of variable intensity reflected from the

ball and the element to generate electrical signals indicative of the detected light

intensity, each detector including an array of sensors for obtaining an image of

the ball, and the element; and e) a controller for controlling the detector of each pair

when the ball passes through the respective fields of view to obtain multiple,

successive images of successive sections of the ball and the element thereon, for

determining the location and shape of the element image, and for processing

changes in the location and shape of the element image to derive the flight

parameters.

26. An apparatus for determining flight parameters of a ball in

flight along a flight path, comprising:

a) a light conditioning element on an exterior surface of the

ball;

b) an emitter-detector pair having a field of view through

which the ball passes during flight;

c) said emitter-detector pair having an emitter for emitting

the emitter for detecting light of variable intensity reflected from the ball and the

element to generate electrical signals indicative of the detected light intensity, said

detector including an array of sensors for obtaining an image of the ball, and the

element; and

d) a controller for controlling the detector of said pair

when the ball passes through the field of view to obtain multiple, successive images of successive sections of the ball and the element thereon, for determining

the location and shape of the element image, and for processing changes in the

location and shape of the element image to derive the flight parameters.