EP0278150A2

EP0278150A2 - Golf game and course simulating apparatus and method

Info

Publication number: EP0278150A2
Application number: EP87305767A
Authority: EP
Inventors: Barry Allen; Neil Johnson; Mark Labbe; Clint Lee; Martin Wacker
Original assignee: Joytec Ltd
Current assignee: Joytec Ltd
Priority date: 1987-02-06
Filing date: 1987-06-29
Publication date: 1988-08-17
Anticipated expiration: 2007-06-29
Also published as: JPS63194680A; ATE81024T1; CA1273705A; EP0278150A3; DE3782039D1; DE3782039T2; EP0278150B1

Abstract

An electronic golf game has a simulated ball assembly (26,27) in which the ball rotates in a plane slightly inclined with respect to the horizontal plane. Adjacent the ball (26) is a row of phototransistors (39,40) which senses the shadow of a golf club which interrupts an overhead light as it approaches the ball (26) for a hit. The row of phototransistors (39,40) is sampled approximately every 6 microseconds until the ball is hit, and the samples are stored in DMA buffer. The stored sampled representation is analyzed to determine club movement parameters for swing analysis and for computing the trajectory and lay of a hypothetical real golf ball. The closest stored video frame of the golf hole fairway is then retrieved and displayed on a video monitor screen (24) to the player, who then takes another shot from the presumed new location of the hypothetical ball.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to electronic and data processing apparatus for simulating a game of golf. More particularly, the apparatus senses golf club movement just before it hits a simulated golf ball in order to predict where on an actual image of a preselected hole terrain it would land with tolerable accuracy. More particularly still, the simulated golf ball, when hit, rotates around a substantially vertical axis, whereupon its speed of rotation may be sensed to aid in the prediction of where an actual ball would land. Furthermore, the present invention relates to a method of representing an actual preselected golf course by photographic or the like means for later display to the user of the apparatus. More particularly, the selected golf terrain is partitioned in segments, each segment is photographed, the photographs are digitized and stored on laser video disc for retrieval and display as a game is played.

Prior Art of the Invention

United States Patent 3,601,408 issued August 24, 1971 to Kenneth K. Wright discloses a Golf Swing Training Apparatus, wherein the time and position of a golf club head are sensed photoelectrically at selected stations during a practice swing. Corresponding characteristics of the swing and of the resulting ball flight are computed electronically and displayed to the player via a panel housing display lights, which indicate to the player one of ten flight designations ranging from "Bobble" to "Hard Hook". Two spaced rows of sensors are provided extending transversely of the swing direction of the club. Two signals are derived from the sensor outputs which represent the positions at which the remote edge of the club shadow crosses the respective rows. The sensors of each row may be placed as close together as required to produce the desired accuracy. The attitude of the club head at impact is determined by two sensors spaced along the club face in front of the simulated golf ball to permit evaluation of swing in terms of "square", "open" or "closed" attitude. The club attitude and swing direction are used for deriving an assessment of the flight characteristics of the ball. In addition to flight characteristics, the swing direction and club attitude are also indicated to the player. Finally, the rate of swing of the club between predetermined points is timed by a clock that operates at variable pulse rates. The clock rate is automatically selected in accordance with the computed flight characteristic computed for the same swing. The clock rates are selected such that the resulting digital output is an appropriate measure of the distance in yards.
United States Patent 3,769,894 issued November 6, 1973 to Robert M. Konklin entitled Golf Game teaches the steps of building a model of a golf hole on a reduced scale, the model having a flat playing surface, and photographing the playing surface from differing points on the model. Scenes illustrating portions of the gold hole are displayed to the golfer on a screen on which a spot of light is projected on the displayed scene where computations predicted the ball's trajectory.
United States Patent 4,343,469 issued August 10, 1982 to Yoshisuke Kunita et al discloses a Golf Game Practicing Apparatus capable of simulating the trajectory of a ball during putts. The trajectory of the ball toward the target are displayed on a screen. By means of a mapping transforming section, which alters the image data of the curved surface, the image of the terrain of the green displayed on the screen changes for each approach of the ball toward the target to depict an image closer to the target than that of the preceding putt. The input to the mapping transforming section is the new putt position and the curved surface data.
United States Patent 4,429,880 issued February 7, 1984 to Richard M. Chen et al discloses a Golf Game Simulator Device which permits the golf player to view a specific golf course or portion thereof on a television monitor and is provided with additional information relating to the lie of ball and its position in relation to the hole. The golfer then hits the ball in the normal manner, which ball is fixedly retained on a joystick apparatus, whereby in striking the ball the joystick transmits signals to a computer which generates graphic data relative to a golf course and converts the signal input to graphic display information relative to the new position or lie of the ball in relation to the hole on the golf course. The golf ball is mounted so that when struck, first and second signals for each of four degrees of movement are transmitted to the computer and correlated with the golf course data input. The device in one embodiment utilizes a video disc whereby the course layout is pictorially viewed on a television monitor in addition to graphic information, and the computer determines the pictorial scene to be displayed depending upon the location of the golf ball after being struck by the golfer.
The patent briefly describes an embodiment utilizing a video disc as follows:
"In FIG.4, there is shown a further embodiment of the system, which further embodiment is generally referred to as system 210. System 210 comprises a base 218, computer 213, cassette 280 and television 215, also similar in design and construction to units 118, 113, 80, and 115, respectively, as afore-described. System 210 further contains a video disc player 90 for playing disc 91. Player 90 receives input from computer 213 and selectively display video information, such as a video image of an actual golf course 230 on screen 221. Disc 91 and cassette 280 are of course coordinated so that generated images are of the same subject matter. In addition, the specific tee location or lie of the ball will have a corresponding view or pre-recorded scene on video disc 91. With the computer determined repositioning of the ball after impact, the computer may first generate graphic information relative to the lie of the ball and then instruct the video player to freeze frame the disc 91 to demonstrate the actual vantage point of the golfer as if the golfer were actually positioned on the course at that ball location. Pre-recorded images on the disc 91 may be at various point locations on the golf course spaced on a grid layout of several meters apart.
In utilizing the video disc player, it is important that the computer in accessing the video disc player be able to locate, skip to or jump to a specific point on the video disc so as to display a scene representative of the specific lie of the ball. A disc skip system useful in this regard is that as disclosed in U.S. Pat. No. 3,993,863, granted Nov.23, 1976 to Leedom, et al."

SUMMARY OF THE INVENTION

The present invention endeavors to provide a compact and realistically simulated golf game apparatus which also has the capability of providing to the user a reasonably accurate analysis of his/her swing.
A feature of the present invention is that as a golf club approaches the ball for a hit the club head presence is sensed by a row of periodically sampled sensors. Samples are stored in successive memory locations such that a digital representation of the club head is obtained just prior to and until the ball is hit. Analysis of the stored representation yields reasonably accurate results of club head speed, attitude, and approach. The shadow of the club shaft as it crosses the row of photosensors is the basis of calculating the vertical approach of the club.
Another feature is that a simulated ball is freely rotatable around a substantially vertical axis to give the user a more realistic feeling of a ball being hit. The speed of rotation is preferably sensed to aid in the determination of how far an actual ball would have travelled. However, such information may be obtained from club head sensing alone, in which case, an actual golf ball on a tee could be used.
According to an aspect of the present invention the club head height may be sensed by means of an ultrasonic sensor placed below the path of the club head adjacent the ball. It sends a short pulse and receives its echo; the elapsed time directly indicates club height.
A further feature of the present invention is a method of photographing a golf course by strategically subdividing a fairway into segments, digitizing and storing the segment photographs for later display during play.
Accordingly, the present invention provides a golf game simulation apparatus, comprising:
simulated golf ball means; a first plurality of sensors arranged in a row on one side of and below the simulated golf ball for sensing a golf club head above; and means for sampling the first plurality of sensors periodically at a predetermined frequency to yield a sampled representation of golf club head movement until the simulated ball is struck by the golf club head.
In a preferred embodiment, the simulated golf ball is at the free end of a substantially horizontal shaft which rotates around a substantially vertical shaft at its other end.
In a narrower aspect, the vertical shaft is slightly inclined frontwards such that the simulated ball comes to rest (by gravity) adjacent the first plurality of sensors.
The apparatus further comprises electronic and data processing means for controlling and processing sampled and stored information.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiment of the present invention will now be described in conjunction with the annexed drawings, in which:

Figure 1 is a perspective view of a golf game simulation apparatus according to the present invention.
Figure 2 is a plan view depicting the rest position of the simulated golf ball of the apparatus in Figure 1.
Figure 3 is a plan view depicting the support mechanism of the simulated golf ball;
Figure 4 is a side elevation of the ball and mechanism shown in Figures 2 and 3;
Figure 5 is an overall block schematic of the electronic and data processing system of the apparatus shown in Figure 1;
Figure 6 is a block schematic of the sensor interface module shown in Figure 5;
Figure 7 is a block schematic of the multiplexer module shown in Figure 5;
Figure 8 is a block schematic of back row photosensors interface circuits interfacing the photosensors shown in Figure 5 to the module of Figure 7;
Figure 9 is a block schematic of front row photosensors interface circuits interfacing the photosensors shown in Figure 5 to the module of Figure 7;
Figure 10 is a plan view of a golf hole fairway illustrating the partitioning of the fairway for purposes of photographing it for digitization and storage on a laser video disc;
Figure 11 is a flow-chart explaining the software of club head movement analysis;
Figure 12 is a flow-chart explaining the software of ball movement parameter computation;
Figure 13 is a flow-chart explaining the software of ball trajectory computation;
Figure 14 is a flow-chart explaining the software for determination of the player's eyeview frame number or address for retrieval and display;
Figure 15 depicts a screen display showing the layout of a selected golf course for player selection of a hole to play; and
Figure 16 depicts a typical screen display of an actual image of the putting green of a selected golf hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to Figures 1-4 of the drawings, the mechanical structure of the golf game apparatus will first be described. A base 20 has an upper surface comprised of two parts 21 and 22; on the extreme end of the surface 22 is erected a housing 23 with a video monitor screen 24 visible at its top and framed by part of the housing 23 which protrudes slightly forward in order to enable light from a lamp 25 underneath the screen 24 to shine downwardly throwing the shadow of objects interrupting it onto the surface 22. From the bottom of the housing 23 at its front protrudes a simulated golf ball 26 mounted on (or integral with) a shaft 27 approximately twelve inches long. The shaft 27 is freely rotatable around a slightly forwardly inclined vertical shaft 28, such that by gravity the ball 26 always returns to its rest position protruding out of bottom opening 29. In order to prevent the shaft 27 from being "stuck" in its quasi-stable position underneath the housing 23 (i.e. 180° away from its forward resting position) three button magnets 30, 31 and 32 are employed. The magnet 30 is disposed adjacent a cylinder 33 integral with and supporting the shaft 27, which is the extension of a tapered portion 34 at the bottom half of the cylinder 33. Embedded in the cylinder 33 at the same level as the magnet 30 is the magnet 31, which is poled to attract the magnet 30 and which is disposed diametrically opposite the shaft 27. This arrangement also provides additional precision in positioning the ball 26 in its rest position. Also embedded in the cylinder 33 is the magnet 32 which is poled to repel the magnet 30 when the shaft 27 is rotated 180° from its forward resting position. The magnet 32 is embedded in the cylinder above the shaft 27 at the same level as the magnet 30.
The upper part of the cylinder 33, in addition to housing the magnets 31 and 32 embedded therein, also serves as a braking surface against which a brake pad 35 is pressed by means of lever 36 which is actuated by solenoid 37 in order to stop rotation of the cylinder (and the ball 26) around the shaft 28 once the ball 26 has been hit by a golf club swinging player (not shown). A return spring ensures that the lever 36 returns to its quiescent position and so the brake pad 35.
The ball 26, the shaft 27 and the cylinder 33 are preferably machined from a single block of a durable synthetic material such as polythylene or the like.
Housed just under the top surface 22 symmetrically on either side of the ball 26 and shaft 27 are two parallel rows (parallel to the shaft 27 of phototransistors 39 and 40, which are 4½ inches apart and which have their lenses pointing upward. The two rows of phototransistors 39 and 40 respond to light or shadow through two transparent protective strips 41 and 42 in the top surface 22. The two rows 39 and 40 are mounted on two printed circuit boards 43 and 44, on each of which are mounted an additional pair of phototransistors 45/46 and 47/48. The phototransistors 45 and 47 are disposed 1 5/8 inches from the rows 39 and 40, respectively, and are exposed to light or shadow via a transparent protective strip 49 in the top surface 22. The function of the phototransistors will be described in conjunction with the electronic data processing circuit description below.
In addition to the two rows of phototransistors 39 and 40, which shall henceforth be termed front rows 39 and 40, there are two back rows (not shown in Figure 2) which are parallel to the rows 39 and 40 and which are mounted on PC boards 43 and 44. One back row is mounted 5½ inches to the right of the front row 39 and the other back row 5½ inches to the left of the row 40.
Turning now to Figure 5, the overall organization of the electronic and data processing system will be described. The system comprises a CPU 50 (which is commercially available as a 8088 (INTEL) motherboard such as that in IBM's XT PC) and its address, data and control bus 51. Connected to the bus 51 are the following subsystems or modules:
- a video disc controller 52 and its associated graphics generator and overlay unit 53 (both are integrated in a commercially available unit "V:Link 1000" from VISAGE); the controller controls a video disc player (SONY) 54, the standard NTSC video output of which is delivered to a video monitor display 55 having a touch responsive screen 24 after having generated graphics (if any) overlayed thereon by the graphic generator 53;
- a CD ROM controller (SONY) 56, which controls CD ROM player (SONY) 57. A floppy disc drive or other random access memory device may replace these CD units;
- a 2 × 8K byte EMPROM 58, which is necessary to contain the program for operating the CD ROM controller 56, and which stores the BIOS program of the CPU 50.
- a microprocessor (8051) in the sensor interface module 59, which responds to the data from the touch screen 24 of the display 55; and
- a multiplexer module 62 which multiplexes and preprocesses signals from: right and left photosensor PC boards 43 and 44, respectively; weight sensor 62; and club height sensor 64 if one is used.
The video disc player 54 accepts laser discs having digitized photographs of selected golf courses as well as menu displays for interacting with the user of the game. Each laser disc has associated with it a CD ROM containing data (apart from pictures) specific to the golf course on the laser disc, such as distances, contour and topographical data of the hole fairways, in addition to the addresses of each photograph stored on the laser disc.
The CD ROM also stores the main game program shown at the flow chart level in Figures 11 to 14.
Figures 6 and 7 show the block diagrams of the sensor interfacer module 59 and the multiplexer module 62, respectively. The sensor interface module 59 comprises a microprocessor 65 (8051), which includes a 4K byte ROM, two programmable timers, a serial input/output buffer, and a parallel input/output buffer which interfaces with the bus 51 of the CPU 50. A decoder and buffer 66 decodes and buffers the bus 51, and enables a solenoid decoder 67 which activates either the brake solenoid 37 or a second solenoid( not shown) to raise the shaft 28, thereby raising the simulated ball 26 to a slightly higher position (¾ inch) above the top surface 22, thus simulating a tee-off position to the player. A 2K byte non-volatile RAM 68 retains vital statistics such as cummulative number of hits, total money intake, and so forth. A 16-bit programmable counter 69 (8254) is a hardware controlled timer which times the golf club movement and starts timing when the respective back row is crossed by the club shadow and stops when the ball 26 is hit.
Since the game apparatus should be usable by right and left handed players, the two PC boards 43 and 44 bearing photosensors on either side of the ball 26 were necessary. In fact, the PC board 44 is identical in construction to the PC board 43 (for reasons of manufacturing economy), but when installed the PC board 44 is rotated 180° and the resultant interchange of photosensor positions is taken care of by the software and hardware. As a result of the right/left hand choice, it is necessary to multiplex the photosensor and other signals in the multiplexer module 62 shown in more detail in Figure 7. Thus the inputs to the multiplexer are duplicate inputs from the right and the left PC boards 43 and 44. For example, MUX 70 accepts data bits DO(R) to D7(R) and D0(L) to D7(L) from the right front row 39 and the left front 40, respectively. In fact, as will be seen below, the front rows 39 and 40 yield twenty-four bits each, time multiplexed into three-times-eight parallel bits.
Likewise, MUX 71 accepts four bits AB0(R) to AB3(R) and AB0(L) to AB3(L), which are the result of preprocessing of twenty-one photosensors in the right and left back rows (one of which is shown as SB0 to SB20 in Figure 8), respectively. The outputs of MUXs 70 and 71 are to the DATA lines on the bus 51.
MUX 72 multiplexes other right/left functions, such as ball hit (BH) signals. These functions will be explained in conjunction with the description of system operation. The output of the MUX 72 also controls ultrasonic sensor and timer in the club height sensor 64, as well as ball timer 73.
Also shown in Figure 7 is a strain bridge 74 and A/D converter 75 in the weight sensor 63. The strain bridge 74 is under the right hand side of the top surface 21 of the platform 20 (in Figure 1) and serves to fix a reference point related to the user's weight prior to commencement of play. The relative departure from that reference weight during club swing action by the player is used to display swing analysis information (i.e. percentage weight distribution between left and right feet as a swing is progressing) to the player following principles well known to those skilled in golf teaching and analysis. The A/D converter 75 converts the analog output of the strain bridge 74 to computer readable data.
Turning now to Figures 8 and 9, which show circuits on either of the identical PC boards 43 and 44, the first shows back row 76 comprising phototransistors, SB0 to SB20, while the latter shows the front row 39 (or 40, of course) comprising phototransistors SF0 to SF22. All phototransistors are manufactured by General Electric and sold under part number GE L14Cl. Due to the circuit used to obtain the necessary sensitivity, it has a high output impedance and it is necessary to buffer the phototransistors prior to any signal processing.
In the circuit for processing the signals from the phototransistors SB0 to SB20 four CMOS buffers 77 to 80 and four associated latches 81 to 84 are utilized. The four buffers 77 to 80 also perform a simple multiplexing function, depending on whether the back row 76 is on the right hand side of the ball 26 or on the left hand side thereof, i.e. whether the board is used as PC board 43 or as PC board 44. When detecting the swing of a club, only the sixteen phototransistors which are closest to the player are utilized. Thus, for example, the buffer 77 selects either the phototransistors SB0 to SB3 (in the case of a right handed player) or SB17 to SB20 (in the case of a left handed player). The remaining buffers 78 to 80 are connected as shown in the drawings. The output of the selected sixteen phototransistors is latched by the latches 81 to 84, the outputs of which is processed by a priority encoder 85 comprising two TTL priority encoder chips 86 and 87 (74LS148) and three NOR gates 88 to 90.
The output of the priority encoder 85 is a four bit word encoding the phototransistor furthest from the player which has been crossed by the golf club shadow.
The four bits AB0 to AB3 are applied to the back row MUX 71 for left/right selection.
In the circuit for processing signals from SF0 to SF22 again CMOS buffers 91 to 93 are utilized, the twenty-three signal bits plus one integrity "toggle bit" ( generated by toggle bit generator 94) are latched by means of tri-state latches 95 to 97, which are enabled in succession to yield a twenty-four bit word time multiplexed in three eight bit words D0 to D7, which eight parallel bits are applied to MUX 70 (Figure 7). The tri-state latches 95 to 97 are controlled by controller 98, which enables them in succession. The controller 98 processes BALL HIT, IOR (In/Out Read) and DACK (DMA Acknowledge) signals from the CPU 50 and outputs a DRQ (DMA Request) signal. The controller 98 comprises a finite-state machine based on TTL shift registers 99 and 100, which generate properly timed control signals to successively enable the latches 95, 96 and 97 to output their latched bytes, and which generate the DMA request signal DRQ.
Figure 10 is an overview of a golf hole fairway 101 having a tee 102, a hole 103 in a putting green 104. In order to be able to simulate a game of golf on the apparatus of the present invention, the fairway 101 is partitioned into horizontal lines every fifty yards. Thus between the tee 102 and the hole 103 there are imaginary horizontal lines 105 to 108, each of which may be partitioned into rectangles reaching twenty-five yards on either side thereof centered around centers such as 109 and 110. The centers on each horizontal line are fifteen yards apart, so that every rectangle is fifty-by fifteen yards. Of course, there may be as many horizontal lines and as many centers per line as desired to obtain a requisite level of accuracy. The point is that during use of the apparatus if the hypothetical golf ball is computed to fall in one of the rectangles centered around a center, such as 109 or 110, the apparatus would display a photograph taken from the respective center in the direction of the hole 103. Therefore, in photographing the fairway 101, a photograph is taken from a center such as 109 looking at the hole 103. In addition, around the hole 103 the putting green 104 and surroundings are partitioned into three concentric areas:
an outer circle 111 of fifty yards diameter, a circle 112 of 35 yards diameter, and a smaller circle 113 of 15 yards diameter. A photograph looking at the hole 103 is taken from points on the circles 111 to 113 at 45° intervals. In addition, a single photograph is taken from a position 114 five yards away from the hole 103. Accordingly, there are twenty-five photographs around the hole 103, while in the example of Figure 10 the fairway 101 yields twenty-eight photographs, for a total of fifty four photographs including the one from above, typically, per golf hole. Rather than take actual photographs, the fairway 101 is video taped and the single video frames are each assigned an address. The full golf course, if so desired, is mastered on tape and then remastered on video disc. Video taping and mastering is available from CTI Communications of Saskatoon, Saskatchewan, Canada. Transfer on video disc is available from the 3M Company, U.S.A. The stored frames are later retrieved for display by means of their address on the video disc. A particular frame, say it was taken from the center 109, is retrieved for display as computations reveal that the hit by a golf club of the simulated ball 26 would have landed a hypothetical ball within the confines of rectangle 115 centered around the center 109. Had the hypothetical ball been computed to hit a tree 116, a further randomising computation would yield a random position of the lay of the hypothetical ball 117 in the vicinity of the tree 116. Likewise, should the lay of the hypothetical ball be computed to fall in water trap 118, the apparatus would display the appropriate frame while the graphics and overlay generator 53 would display a splash 119 in the water trap 118.
System operation will now be described with reference to the preceding drawing figures and Figures 11 to 14 showing flow charts of system software.
As use of the installed apparatus as shown in Figure 1 commences, the player is prompted by a screen message to stand on the right hand side of the top surface 21 in order to obtain a reference reading of the players weight by means of the strain bridge 74 located underneath. Changes in weight relative to the reference reading, which are registered by the strain bridge 74 during swing action, are recorded and provide swing analysis information to the player later on if requested.
Once the weight calibration is completed, the player is prompted by a screen message to indicate a choice between right handed and left handed swing by touching the appropriate area on the display screen 24. This will determine which of the two printed circuit boards 43 and 44 will be the primary operative board and the software is configured accordingly.
From the video disc in the player 54 the overall layout of the golf course, as shown for example in Figure 15, is retrieved and displayed to the player on the screen 24 for selection of the hole the player wants to play. Once selection is completed by the player having touched the appropriate hole number on the screen 24, a top view of the hole fairway, such as that shown in Figure 10 without the explanatory markings, is displayed to the player with the relevant information such as distance between the tee 102 and the hole 103.
The interaction between the player and the machine continues via screen prompting and messages to which the player reacts by making a choice. For example, since the player is using actual golf clubs to hit the ball 26, an array of standard golf clubs is displayed to the player where a choice is indicated by touching the screen to select a club identical to the one that the player will actually use.
Let us now assume that a player, has selected a hole and a club, and that the first eyeview picture from the tee 102 is displayed on the screen 24. Once the player commences the swing and the club shadow passes the back row 76 phototransistors the priority encoded bits AB0 to AB3 from the priority encoder 85 indicate to the CPU 50 the phototransistor in the back row 76 which is furthest away from the player. This is the only set of data that is provided from the back row 76, and it is latched but held only if the ball 26 hit is indicated by the shaft 27 crossing the phototransistor 47 in the PC board 44. The BALL HIT signal starts the ball timer 73, while the shadow crossing of the shaft 27 of SF4 for left-handed swings and SF18 for right-handed swings stops the ball timer 73. Otherwise, if no ball hit is indicated, a false swing is indicated after approximately sixty-five mS, for example when the player is merely addressing the ball.
It should be noted at this point that when the player hits the ball the default aim point is the hole 103. Should the player during play wish to change the default aiming direction of the system, for example because of a particular lay of the ball, the player may do so by requesting the overall view of the fairway 101 to be displayed and by touching the screen at the chosen aiming point. The change in aiming direction is then accomplished by the system with simple coordinate transformation through an appropriate software routine.
Among other things initiated by the shadow of the club crossing the back row 76, is that continuous sampling of the front row 39 phototransistors is commenced every nine clock cycles, i.e. every 7.54 uS, until the ball 26 has been hit by the club. Every sampling of the front row 39 produces twenty-four bits that are transferred in three-times-eight parallel bits via direct memory access of the CPU 50. Thus when the direct memory access controller chip (8237A-5) grants a DMA request, the front row interface circuit shown in Figure 9 transfers three bytes of information directly into the CPU's 50 random access memory. Each of the phototransistors SF0 to SF22 in the front row 39 corresponds to one bit in the three-byte word transferred, where a ONE indicates that the corresponding phototransistor is under the golf club's shadow. Because the PC boards 43 and 44 are identical, as mentioned earlier, data for the right hand swing is transferred with the phototransistor SF22 nearest the player; while data for a left hand swing is transferred with the phototransistor SF0 nearest the player. The bit number 23 in the three-byte word does not correspond to any phototransistor, but toggles between ZERO and ONE once every sampling. The toggle bit serves as an error checking bit in the programming to ensure that the information is being transferred correctly. DMA transfers continue every nine clock cycles until the ball is hit with the bytes stored in consecutive memory locations in a 60K DMA memory buffer, the pointer of which, once the buffer is full, is automatically reset to the top of the buffer. This "wrap-around" continues until the ball 26 is hit as indicated by the photosensor 47. With a DMA buffer size of 60K bytes, it is possible to measure club swings as slow as approximately .5 miles per hour. Once the sampling of the front row 39 is completed, the DMA buffer memory will contain several thousand successive frames or "snapshots" of the profile of the club's shadow as it passed over the front row 39. It is now possible to compute club parameters, such as club velocity, horizontal approach angle, impact positions, face angle, and vertical approach angle. The computation of this parameters will now be discussed with particular reference to the flow chart shown in Figure 11.
The club shadow is analyzed to give a snapshot of the leading edge of the club as it crosses the front row 39 in the form of an array giving the time of crossing for each sensor relative to the time of crossing of the first sensor crossed. From the leading edge array the position of the club as it crosses the front row 39 can be calculated as well as the club face angle.
The horizontal approach angle Haa is computed as follows:
Tbb = time for club to travel from back row to ball
Sbb = separation between backrow and ball
VcMag = club speed = Sbb/Tbb
Sbf = separation between back row and front row
Fcp = club position at front row
Bcp = club position at back row
Ssens = photosensor separation ( = 0.5 inch)
The club face angle Cfa is computed as follows:
Tcc = time count at sensor closest to center of club
Tcf = time count one sensor from center sensor farthest from player
Tcn = time count one sensor from center sensor nearest to player
Count = number of timer counts between front row sensor readings
The vertical approach angle Vaa is computed as follows:
Shfta= tangent of the angle that the club shaft makes with the vertical
Shda = tangent of the angle that the shadow makes with the front row (39)
HL = height of light (25)
Calculation of ball movement parameters is now explained with reference to Figures 12 and 13. The routine that calculates the ball movement parameters takes the club head analysis data and uses this data to calculate the ball velocity Vb and the ball spin vector Spin as follows:
Vb = VcMag (NormFact.VcNorm + TanFact.VcTan)
Spin = SpinMag.SpinDirn, where

CfNorm = unit vector normal to face of club
Cla = club loft angle
α = Cfa + Vaa
CfNorm_x= tan(Cfa) cos (α)
CfNorm_y = (cos (α) + tan (Cfa) .sin (α) .Shfta)
CfNorm_z = (sin(α) - tan (Cfa) .cos (α) .Shfta) (CfNorm is now converted to a unit vector)

VcDirn = unit vector in direction of club velocity
VcNorm = component of club velocity normal to club face
VcTan = component of club velocity tangent to club face
SpinDirn = unit vector in the direction of the spin vector
SpinMag = magnitude of spin vector
NormFact = factor translating normal component of club velocity based on impact dynamics
TanFact = factor translating tangential component of club velocity based on impact dynamics
SpinFact = factor translating club speed to spin magnitude

VcDirn_x = cos(Vaa). sin(Haa)
VcDirn_y = cos(Vaa). cos(Haa)
VcDirn_z = sin(Vaa)
VcNorm = innerprod (CfNorm, VcNirn). Cfnorm
VcTan = VcDirn - VcNorm
SpinDirn = vectorprod (VcDirn,CfNorm)
SpinMag = SpinFact .Vcmag
The eyeview calculation which yields the address of the picture to be retrieved from video disc player 54 is explained with particular reference to Figure 14. The calculation of the eyeview for a given location on the golf course is determined from three arrays. The first of these defines the areas on the course for which a particular eyeview will be displayed. It is a two dimensional array which defines a sequence of up to 12 contiguous intervals (i.e. rectangles such as 115 in Figure 10) for each screen row 105 to 108. It is of the form Xmin[Row,i] where 0<Row<191 and 1<i<12. The entries in this array are the left hand endpoints of the intervals. The second array defines the eyeview number for each of the areas defined by the Xmin array. It is of the Form Eview=Mat[Row,i] and each element gives the eyeview number corresponding to the area containing the interval defined by Xmin. The third array is the eyeview table. It is of the Form Frame=Mat[Eview] where 1<Eview<MaxEview. The entries in this table are the actual frame numbers on the video disc corresponding to the eyeview number.

Claims

1. Golf game simulation apparatus, comprising:
simulated golf ball means;
a first plurality of sensors arranged in a row on one side of and below said simulated golf ball for sensing a golf club head above; and
means for sampling said first plurality of sensors periodically at a predetermined frequency to yield a sampled representation of golf club head movement until said simulated ball is struck by said golf club head.

2. The golf game simulation apparatus of claim 1, said simulated golf ball means being an actual golf ball.

3. The golf game simulation apparatus of claim 1, said simulated golf ball means comprising a substantially horizontal shaft having a ball-like enlargement at its free end.

4. The golf game simulation apparatus of claim 3, said substantially horizontal shaft supported at its other end by means of, and rotatable around, a substantially vertical shaft.

5. The golf game simulation apparatus of claim 4, said substantially vertical shaft being slightly inclined frontwards such that said simulated golf ball comes to rest adjacent the first plurality of sensors.

6. A golf game simulation apparatus having a simulated golf ball assembly, comprising a first shaft supported at one end thereof to freely rotate around a predetermined axis and having at its other end a golf ball-like attachment.

7. The golf game simulation apparatus as defined in claim 6, said first shaft being substantially horizontal.

8. The golf game simulation apparatus as defined in claim 7, said first shaft freely rotatable in a substantially horizontal plane.

9. The golf game simulation apparatus as defined in claim 6, said first shaft supported at one end thereof by means of a second stationary shaft slightly inclined with respect to the vertical such that said golf ball-like attachment comes to rest always at a predetermined position by action of gravity.

10. The golf game simulation apparatus as defined in claim 9, said golf ball-like attachment being integral with said first shaft, and said first shaft rotating around said second shaft by having the second shaft inserted through a pivoting aperture in said first shaft.

11. The golf game simulation apparatus as defined in claim 10, further comprising braking means adapted to engage a cooperating surface of a portion of said first shaft to brake its free rotation around said second shaft.

12. A method of recording still pictures or frames of a hole fairway in a golf course comprising the steps of:
recording a plurality of still pictures or video frames from a plurality of radial points symmetrically disposed around the hole and lying on at least three concentric circles around the hole, each of said concentric circles having a predetermined diameter;
assigning a retrieval address to each of said pictures or still frames; and
storing said pictures or still frames each at its retrieval address in a random access storage medium.

13. Golf game simulation apparatus comprising, golf ball simulation means, means for sensing movement of a golf club head towards said golf ball simulation means, means for obtaining from said sensing means a digital representation of the movement of the golf club head, and means to simulate the golf game utilising said digital representations.

14. Apparatus according to claim 13, wherein said sensing means comprises an array of photosensors.