AU2006252120B2 - Billiard game input device, billiard game system, game input device, and computer program - Google Patents

Description

S&FRef: 617211D1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address Konami Corporation, of 4-1, Marunouchi 2-chome of Applicant : Chiyoda-ku, Tokyo, Japan Actual Inventor(s): Koki Atobe Takashi Hamano Hideki Hashimoto Hiroshi Kinomoto Ryo Mahara Address for Service: Spruson & Ferguson St Martins Tower Level 35 31 Market Street Sydney NSW 2000 (CCN 3710000177) Invention Title: Billiard game input device, billiard game system, game input device, and computer program The following statement is a full description of this invention, including the best method of performing it known to me/us: 5845c(614305_1) BILLIARD GAME INPUT DEVICE, BILLIARD GAME SYSTEM, GAME INPUT DEVICE, AND COMPUTER PROGRAM BACKGROUND OF THE INVENTION 5 Field of the Invention The present invention relates to a billiard game system that causes a player to shoot a simulative ball and an input device and computer program suitable to such a game system. 10 Description of the Related Art As aninputdeviceof a billiard game system that reproduces a feeling of shooting a cue ball, in Japanese Patent Application Laid-Open No. 2001-178966 (hereinafter, referred to as reference 1) , there is disclosed an input device comprising: a simulative 15 ball supported by a guiding mechanism; a shooting signal output device for outputting a signal that corresponds to a shooting force when the simulative ball is shot by a cue or its substitute or a displacement speed of the simulative ball; and a shooting point signal output device for outputting a shooting point signal 20 that corresponds to the shot position of the simulative ball. In Japanese Patent Application Laid-Open No. 2000-93655 (hereinafter, referred to as reference 2) , there is disclosed an input device in which: a tip end of a rod simulating a cue is housed in a predetermined case in a state in which the tip 25 end can be moved in its axial direction; a magnet is mounted on the tip end of the rod, and a coil is disposed at the periphery of its tip end; and when the rod moves in the axial direction, a cue ball shooting speed is specified based on a dielectric current generated at the coil. In United State Patent No. 6220963 (hereinafter, referred toas reference 3) , there isdisclosedaninputdevicecomprising: 5 a housing such as a mouse utilized as a computer's pointing device; and a receiving portion mounted on the housing, the receiving portion supporting the tip end of the cue, wherein a cue operation is detected by means of an optical reader and an optical reading roller mounted on the housing or the receiving portion. 10 In an actual billiard game, there exist a variety of shots for shooting the cue ball in a specific direction off its core such as follow shot, draw shot, or jump shot, and a variety of operations are provided to the cue ball by these shots. However, as in the input device of reference 1, in the casewherea simulative 15 ball is supported by a shaft, movement of the simulative ball is restrictedmore significantly than an actual cue ball according to its support structure. Thus, depending on a position at which the simulative ball is shot (a shooting point) or a shot angle, a feeling when the actual cue ball is shot cannot be reproduced. 20 sufficiently. Intheinputdevicedescribedinreferencel, thesimulative ball is structured so that the simulative ball can be divided into two sections, i.e., a side at which the player shoots and its opposite side. A hemispherical portion at the side at which 25 the player shoots is connected to a volume detector of the inside of the simulative ball. Then, a shootingpoint of the simulative ball or an angle at which the ball is shot is detected based 2 on an output of such a volume detector. In the case where the simulative ball itself is thus divided into sections, as the simulative ball itself is displaced, it is difficult to reproduce the feeling when the actual cue ball has been shot and the 5 construction of the simulative ball becomes complicated as well. Inaddition, inreference 1, thereisdisclosedanexamplewherein a pressure sensing film or a pressure sensing rubber is provided on a surface of the simulative ball, thereby detecting a shooting point and an angle at which the ball has been shot. However, 10 in this case as well, the feeling when the simulative ball has been shot changes depending on a material for such a pressure sensing film or pressure sensing rubber, thus it is difficult to reproduce the feeling when the cue ball has been shot in the same way as that described previously. 15 In the input device of reference 2, no simulative ball essentially exists, and the feeling when the cue ball is actually shot cannot be reproduced. Moreover, the input device of reference 2 is arranged to hold the tip end of the rod simulating the cue in a case. Thus, it is required to rotatably provide 20 the case itself in thehorizontal direction or vertical direction around a predetermined fulcrum in order to change the rod operation direction. As a result, the rod operation is restricted to a rotational motion around the fulcrum of the case, and thus the player cannot carry out an operation such that the player shoots 25 a cue in an arbitrary direction relevant to the cue ball. Therefore, rod operation is different from actual cue operation, and in this respect as well, the reality is degraded. 3 The input device of reference 3 as well is not arranged to shoot the simulative ball, and the feeling when the cue call is actually shot cannot be reproduced. In addition, in the input device of reference 3, a variety of 5 detecting devices are built in the housing or the receiving portion, thus making it necessary to operate the cue while the tip end of the cue is guided by its receiving portion. Thus, a shot using a rest (referred to as a bridge) formed by the player's fingers cannot be carried out, and actual 10 cue operation cannot be sufficiently reproduced. Further, in the device of reference 3, when the receiving portion is pushed down by the cue, a signal indicating that the cue ball has been shot is generated. Such an operation is unnatural, and the reality of shots is further degraded. 15 SUMMARY According to an aspect of the invention, there is provided a billiard game system comprising a simulative ball movably provided in a predetermined direction from a 20 predetermined shot position as an object to be shot by a player; a plurality of image acquiring devices for outputting data on images of a predetermined detection range set in a direction in which the player shoots, which are scanned from viewpoints different from each other relevant 25 to the simulative ball at the shot position; a coordinate specifying device for specifying a three-dimensional coordinate of at least two typical points of a cue in a three-dimensional coordinate system set with respect to the detection range based on data outputted from each image 30 acquiring device; a position/angle specifying device for specifying a shooting point and a shot angle of the simulative ball based on the coordinate of the typical points of the cue specified by the coordinate specifying -4device; a speed information detecting device for detecting information correlated with a speed of the simulative ball; a speed specifying device for specifying a speed at which the simulative ball has been shot based on information 5 detected by the speed information detecting device and a computing device for computing an operation of a virtual cue ball to be displayed on a screen of a predetermined display unit in correspondence with the simulative ball based on the specified shooting point, angle, and speed; wherein a lo respective one of the plurality of image acquiring devices outputs data that corresponds to a projected image onto each scanning plane different from each other, the scanning planes being set in the three-dimensional coordinate system, and wherein the coordinate specifying device comprises a 15 two-dimensional coordinate acquiring device for acquiring a two-dimensional coordinate of points that correspond to the typical points of a cue image included in the image scanned by each image acquiring device; a straight line specifying device for referring to information associated with the 20 three-dimensional coordinate assigned in advance to a respective one of the viewpoints and the scanning planes, thereby converting the two-dimensional coordinate of each point acquired by the two-dimensional coordinate acquiring device into the three-dimensional coordinate system, and 25 then, specifying straight lines that connect each point at which the three-dimensional coordinate has been assigned and each viewpoint corresponding to each of the scanning planes to which each of the points belongs and a typical point coordinate determining device for determining a three 30 dimensional coordinate of each of the typical points on the cue from a mutual relationship between the specified straight lines. -5- According to another aspect of the invention, there is provided a game input device comprising a simulative ball movably provided in a predetermined direction from a predetermined shot position as an object to be shot by a 5 player; a plurality of image acquiring devices for outputting data on images of a predetermined detection range set in a direction in which the player shoots, which are scanned from viewpoints different from each other relevant to the simulative ball of the shot position; a coordinate 10 specifying device for specifying a three-dimensional coordinate of at least each two typical points, of a rod shaped member in a three-dimensional coordinate system set with respect to the detection range based on the data outputted from each of the image acquiring devices and an is information generating device for generating information required to specify a state in which the simulative ball has been shot, based on a coordinate of the typical points of the rod shaped member specified by the coordinate specifying device; wherein a respective one of the plurality of image 20 acquiring devices outputs data that corresponds to each projected image onto scanning planes different from each other, the scanning planes being set in the three dimensional coordinate system, and wherein the coordinate specifying device comprises a two-dimensional coordinate 25 acquiring device for acquiring a two-dimensional coordinate of each point that corresponds to each of the typical points of an image of the rod shaped member included in the image scanned by each image acquiring device; a straight line specifying device for referring to information associated 30 with the three-dimensional coordinate assigned in advance to a respective one of the viewpoints and the scanning planes, thereby converting the two-dimensional coordinate of each point acquired by the two-dimensional coordinate acquiring -6device into the three-dimensional coordinate system, and then, specifying straight lines that connect each of the points at which the three-dimensional coordinate has been assigned and each of the viewpoints corresponding to each of 5 the scanning planes to which each of the points belongs; and a typical point coordinate determining device for determining a three-dimensional coordinate of each of the typical points on the rod shaped member from a mutual relationship between the specified straight lines. 10 According to yet another aspect of the invention, there is provided a computer program for, based on data on an image outputted from a respective one of a plurality of image acquiring devices for scanning a predetermined detection range from viewpoints different from each other, is recognizing a rod shaped member poked in the detection range, the computer program causing a computer to function as a coordinate specifying device for specifying a three dimensional coordinate of at least two typical points of the rod shaped member in a three-dimensional coordinate system 20 set with respect to the detection range based on data outputted from each image acquiring device and an information generating device for generating information required to specify a state in which a predetermined target disposed in the three-dimensional coordinate system has been 25 shot by the rod shaped member based on a coordinate of each of the typical points of the rod shaped member specified by the coordinate specifying device. This computer program is executed by a computer, whereby the computer can function as a variety of devices of 30 the input device according to the present invention. -7- BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a billiard game machine comprising an input device according to one embodiment of the present invention; 5 FIG. 2 is a perspective view showing the input device 10 15 20 25 30 [THE NEXT PAGE IS PAGE 23] -8provided at the game machine of FIG. 1, a part of which is shown in a cutout manner; FIG. 3 is a perspective view showing an internal structure of a base portion provided at the input device of FIG. 2; 5 FIG. 4 is a longitudinal cross section view taken along a transverse direction of the base portion of FIG. 3; FIG. 5 is a sectional view taken along the line V-V of FIG. 4; FIG. 6 is a sectional view taken along the line VI-VI of 10 FIG. 4; FIG. 7A and FIG. 7B are views showing disposition of an image sensor; FIG. 8 is a block diagram depicting a construction of a control system in the billiard game machine of FIG. 1; 15 FIG. 9 is a flow chart showing procedures for cue detection processing executed by a CPU of FIG. 8; FIG. 10 is a flow chart following that of FIG. 9; FIG. 1lA to FIG. 11F are views showing an example of image processing executed by the processing of FIG. 9; 20 FIG. 12A and FIG. 12B are views illustrating computing procedures executed by the processing of FIG. 10; FIG. 13 is a flow chart showing procedures for shot determination processing executed by the CPU of FIG. 8; FIG. 14 is a flow chart following that of FIG. 13; 25 FIG. 15 is a flow chart showing procedures for speed detection processing executed by the CPU as a subroutine process of FIG. 14; 23 FIG. 16 is a view showing an example of image displayed on a monitor by the processing of FIG. 13; and FIG. 17 is a view showing an example of image displayed on a monitor by the processing of FIG. 14. 5 DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a perspective view showing an appearance of a billiard game machine according to one embodiment of the present invention. This billiard game machine 1 (hereinafter, simply 10 referred to as a game machine) is composed as a commercially available arcade game machine installed in an amusement space of a so called game shop or the like. The game machine 1 has a chassis 2; a monitor 3 mounted at the upper part of the chassis 2; and speakers 4, 4 mounted upwardly thereof. At the frontal 15 side of the chassis 2, there is provided a table portion 5 simulating a table of an actual billiard board. A coin entry port 5a and a return port 5b are provided in front of the table portion 5. At the center of an upper face 5c of the table portion 20- 5, a stuff cloth 6 is laid from the frontal side to the depth. An explanatory panel 7 and a control panel 8 are provided respectively at the right and left sides thereof. Fiveoperating buttons 9a to 9e consisting of push button switches are provided on the control panel 8. The number and location of the operating 25 buttons may be changed as required. In an example of FIG. 1, an OK button 9a is provided at the center of the panel, and an up button 9b, a down button 9c, a left button 9d, and a right 24 button 9e are provided so as to surround the OK button 9a longitudinally and transversely. An input device 10 according to the present invention is provided at the rear of the table portion 5. The input device 5 10 has: a base portion 11 disposed so as to be embedded in the table portion 5; and a top portion 12 provided so as to cover the base portion 11. An upper face 11a of the base portion 11 is identical to an upper face 5c of the table portion 5 (precisely identical to the stuff cloth 6), and a table face Ts is composed 10 of these upper faces 5c and lla. A space 13 is provided between the table face Ts and top portion 12, and a simulative bal 14 is disposed there. The space 13 opens forwardly of the chassis 2. A player can shoot the simulative ball 14 by inserting a cue (not shown) into the space 13 through its opening. As a 15 cue of the game machine 1, a real cue used in actual billiard may be used or its substitute may be used. Any rod shaped member extending straightway can be used as a cue. FIG. 2 is a perspective view showing the top portion 12 of the input device 10, a part of which is shown in a cutout 20 manner. FIG. 3 is a perspective view showing an internal structure of the base portion 11. The base portion 11 has a main body 15; and a support mechanism 16 disposed in the inside of the main body 15, the support mechanism 16 supporting the simulative ball 14. The main body 15 has a substrate 17, wall 25 plates 18 ... 18 suitably mounted on the substrate 17, and a table top 19 mounted at the upper end of the wall plate 18. An extraction window 19a is provided on the table top 19. This 25 extraction window 19a is covered with a semitransparent cover 20 (refer to FIG. 5). The support mechanism 16 movably supports the simulative ball 14 between a shot position on the table top 19 and a standby 5 position that falls at the rear of the game machine 1 passing through an opening 19b of the table top 19, as indicated by the arrowinFIG. 2andFIG. 3. Inaddition, thismechanism16 restores the simulative ball 14 from the standby position to the shot position. A detailed description of the support mechanism 16 10 is given below. As shown in FIG. 4 and FIG. 5, the support mechanism 16 has: a pair of bearings 22, 22 mounted on a substrate 17 via a bracket 21; a bearing base 24 turnably supported by these bearings 22, 22 via spindles 23, 23; a bearing 25 fixed to the 15 upper end of the bearing base 24; and a ball axis 26 inserted into the bearing 25. The simulative ball 14 is fixed at the tip end of the ball axis 26, and the center of the simulative ball 14 is positioned on the axle of the ball axis 26. A total mass of the simulative ball 14 and ball axis 26 is equal to that 20 of the cueball usedinactualbilliard. Inaddition, thediameter of the simulative ball 14 is equal to that of the cue ball used in actual billiard. A material for the simulative ball 14 may be the same as that for actual cue ball. As isevidentfromFIG. 5, theballaxis 26has: anengagement 25 portion 26a that is slidable along the axial direction and rotatably engaged around the axle relevant to the bearing 25; a large diameter portion 26b having its diameter greater than 26 the engagement portion 26a; and a flange 26c fixed at the lower end of the engagement portion 26a. A stepped portion between the large diameter portion 26b and the engagement portion 26a comes into contact with the upper end of the bearing 25, whereby 5 a drop of the ball axis 26 is inhibited. The engagement portion 26a is formed to be longer than engagement length of the bearing 25. Therefore, the simulative ball 14 can be pulled up together with the ball axis 26 until the flange 26c comes into contact with the upper end of the bearing base 24. The simulative ball 10 14 and ball axis 26 can rotate integrally relevant to the bearing 25. In this manner, the simulative ball 14 is provided movably in the axial direction of the ball axis 26 supporting the ball (refer to the arrow LM of FIG. 5) and rotatably round the axle 15 of the ball axis 26 (refer to the arrow RM). Thus, when a player shoots the simulative ball 14 off its core in order to apply a so called spin, the simulative ball 14 can escape vertically or rotate according to the degree of displacement of such a shot. In this manner, the feeling of shooting can be simulated to the 20 feeling when an actual cue ball has been shot in spite of a construction in which the simulative ball 14 is constrained by the support mechanism 16. As shown in FIG. 4, the support mechanism 16 has a pair of spindles 23 and a motor 28 connected via a coupling 27. In 25 this manner, the simulative ball 14 can be restored from a standby position P2 (a position indicated by a virtual line in FIG. 5) to a shot position P1 (a position indicated by a solid line in 27 FIG. 5) by the power of the motor 28. In addition, a detection plate 29 is mounted on a side face of the bearing base 24 of FIG. 4 (left side face of FIG. 4) . As shown in FIG. 6, a sensor support plate 30 is mounted on the bracket 21, and three photo 5 sensors 31 to 33 are mounted on the sensor support plate 30. These photo sensors 31 to 33 have slit shaped sensing portions 31a, 32a, and 33a. The simulative ball 14 rotates around the spindle 23, whereby the detection plate 29 can be protruded or recessed relevant to the sensing portion 31a, 32a, or 33a of 10 the photo sensor 31, 32, or 33. When the simulative ball 14 is set at its shot position, the detection plate 29 is inserted into the sensing portion 31a of a first photo sensor 31, whereby an output signal of the first photo sensor 31 is set to ON, and output signals of the other photo sensors 32 and 33 are set to 15 OFF. When the simulative ball 14 starts rotation toward its standby position, the detection plate 29 passes through the sensing portion 32a of the second photo sensor 32, while the output signal of the photo sensor 32 is set to ON. When the simulative ball 14 reaches its standby position, the detection 20 plate 29 is inserted into the sensing portion 33a of the third photo sensor 33, and the output signal of the photo sensor 33 is set to ON. The first photo sensor 31 functions as a simulative ball operation detecting device and a speed information detecting device. The second photo sensor 32 functions as a speed 25 information detecting device. Other sensors such as a proximity switchmaybeusedinsteadofthephoto sensors 31 to 33. However, in order to guarantee smooth movement of the simulative ball 28 14, it is desirable that a sensor be of non-contact type. In the above support mechanism 16, the bearings 22, 22 function as a support portion 16a, and spindles 23, 23, bearing base 24, bearing 25, ball axis 26, anddetection plate 29 function 5 as a link portion 16b, respectively. A bearing portion 16c is composed of the bearing base 24 and bearing 25. In addition, the large diameter portion 26b of the ball axis 26 and the flange 26c correspond to a stopper device, the motor 28 corresponds to a driving device, a pad 34 corresponds to a buffering device, 10 and an illumination lamp 35 corresponds toan illumination device, respectively. As shown in FIG. 2, a top portion 12 has: a hood 36 that covers a space 13 formed between the top portion 12 and an upper face 11a (corresponding to a table face) of a base portion 11; 15 and a pair of image sensors (image acquiring device) 37, 37 incorporated in the hood 36. The image sensor 37 scans a cue shot toward the simulative ball 14, and outputs the scanned image as image data of predetermined dot number and predetermined gradations. A rectangle-shaped, punched hole 36a restricting 20 the viewing field of each image sensor 37 to a predetermined range, for example, is formed at the hood 36. The hood 36 functions as a device for suppressing an effect of external light on the range scanned by the image sensor 37. In addition, this hood 36 also functions as a device for restricting the range of access 25 of the cue to the simulative ball 14 so that the cue shooting the simulative ball 14 always passes through the range detected by the image sensors 37, 37. 29 A contrast between a cue when seen from the image sensor 37 and a cover 20 of its background increases due to the illumination light from the above described illumination lamp 35, and the cue recognition rate is improved. The cover 20 5 scatters illumination light from the illumination lamp 35, and the brightness of the cue background portion is uniformed. As an image sensor 37, there can be utilized a 32 dots x 32 dots version of an artificial retina LSI available from Mitsubishi Electric & Machinery Co., Ltd., for example. 10 FIG. 7AandFIG. 7Bshowa relationshipbetween disposition and viewing field of a pair of image sensors 37. FIG. 7A is a view showing a state seen from the frontal side of the game machine 1. FIG. 7B is a view showing a state seen from the upward direction. The viewing fields (scanning range) 40, 40 of each 15 image sensor 37 are as shown by hatching, and the superimposed range of the viewing fields of both sensors 37 is obtained as a cue detection range 41. As shown in FIG. 7A, the image sensors 37, 37 are disposed so that the respective optical axes AX1, AX2 pass through the center position of the simulative ball 14 20 viewed from the frontal side of the game machine 1 and the optical axes AX1, AX2 are inclined at an angle 0 laterally equal to each other relevant to a vertical line V passing through the center of the simulative ball 14. The angle 0may be properly set, and is set at 45 degrees, for example. A viewing angle k of each 25 image sensor 37 is set to 40 degrees, for example. In addition, as shown in FIG. 7B, the image sensors 37, 37 are disposed at the same position with respect to the forward/backward direction 30 of the game machine 1, and the respective viewing fields 40 extend forwardly of the game machine 1 (to the lower side of FIG. 7B) from the vicinity of the frontal end of the simulative ball 14. The dispositions of FIG. 7AandFIG. 7B are provided as one example, 5 and various modifications can occur. For example, one image sensor 37 may be disposed from the top of the simulative ball 14 to the vertical downward direction, and the other image sensor 37 may be disposed fromthe left side or right side of the simulative ball 14 to the horizontal direction. 10 FIG. 8 is a block diagram depicting a construction of a control system in the game machine 1. The game machine 1 comprises a CPU 50 composed of microprocessors. In the CPU 50, as an input device, there are provided: the above described operating buttons 9a to 9c; photo sensors 31 to 33; image sensors 37, 37; and a 15 coin authentication unit 51. The coin authentication unit 51 judges the truth or falseness of coin entered through a coin entry port 5a (refer to FIG. 1) . In the case where a true coil is entered, this unit outputs a predetermined coin entry signal to the CPU 50. When a signal indicating that a predetermined 20 number of true coins have been entered is outputted from the coin authentication unit 51, a predetermined billiard game is started under the control of the CPU 50. An interface unit is properly provided between each of these input devices and the CPU 50, although not shown. 25 In addition, to the CPU 50, there are connected: a ROM 52 having recorded therein a program for controlling basic operations such as startup processing of the game machine 1; a work ROM 53 for providing a work region to the CPU 50; a game program storage unit 54 having recorded therein a variety of programs and data required to execute a predetermined billiard game in the game machine 1; an image processing unit 55 for 5 depicting an image on a video memory (not shown) in accordance with an instruction from the CPU 50, and converting the depicted image into a video reproduction signal, thereby outputting the converted video reproduction signal to a monitor 3; a sound processing unit 56 for carrying out pronunciation processing 10 according to an instruction from the CPU 50, thereby outputting a sound reproduction signal to a speaker 4; and a motor drive unit 57 for driving a motor 28 of the input device 10 in accordance with an instruction from the CPU 50. For the game program storage unit 54, there can be used a variety of computer readable storage 15 media including a magnetic storage medium such as a nonvolatile semiconductor storage device or a hard disk, for example, or an optical storage medium such as DVD-ROM or CD-ROM. Now, a variety of processing functions executed by the CPU 50 based on a program recorded in the game program storage 20 unit 54 will be described here. FIG. 9 and FIG.10 are flowcharts showing procedures for cue detection processing executed by the CPU 50 to detect a cue based on an image outputted from the image sensor 37. This cue detection processing is repeatedly executed in a predetermined 25 cycle (for example, a cycle of 60 times per second) . This detection processing includes: processing for acquiring a two-dimensional coordinate of a cue image included in a 32 two-dimensional image acquired by each image sensor 37 (steps Sl to S8) ; and processing for obtaining a three-dimensional coordinate concerning two typical points on a cue based on the acquired two-dimensional coordinate (steps S1l to S18). 5 An object of the processing for acquiring the two-dimensional coordinate of the cue is to obtain an image 103 on a difference between a base image 100 shown in FIG. 1lA and an image 101 including a cue image 102, and then, obtain a two-dimensional coordinate of the cue image 102 in the image 10 103. As its preprocessing, this processing further includes processing for serially updating the base image 100 (steps S2 to S4). Hereinafter, a description will be given in order. In cue detection processing, first, a two-dimensional image scannedby one image sensor 37 is acquired (step S1). Next, 15 a difference between the acquired image and an image of the same sensor 37, the image being acquired during previous processing, is acquired (step S2). For example, if an image 101A of FIG. llD is obtained as a previous image, and an image 101 of FIG. 11E is obtained as a current image, an image 104 on a difference 20 as shown in FIG. 11F is acquired. The images 101A and 101 of FIG. 11D and FIG. 11E include a background 105 and a cue image 102. In the differential image 104, an image 106 corresponding to the range in which the tip end of the cue has moved between the previous processing and the current processing is acquired. 25 Then, the processing goes to the step S3 of FIG. 9 in which a position of a tip end 102a (refer to FIG. 11E and FIG. 11F) of a cue image 102 in the currently scanned image 101 is specified 33 based on the differential image 104. Then, the base image 100 is updated relevant to a range (enclosed in thick line frame in FIG. 11E) which is more distant than the tip end (a point on the center line of the cue) 102a of the cue image 102 (step 5 S4). Namely, of the base image 100, the range which is more distant than the tip end 102a of the cue is replaced with the currently acquired image 101. The base image 100 is thus replaced because the cue recognition capability is improved by maximally eliminating an 10 effect which a brightness change in the cue detection range 41 imparts to gradation of an image acquired by the image sensor 37. In addition, only a portion which is more distant than the tip end of the cue is updated because any other portion includes the cue image 102, and thus, cannot be used as the base image 15 100. After updating the base image 100, the cue image 102 is detected from a difference between the current image 101 and the base image 100 (step S5). Then, a predetermined position of the detected cue, i.e., a coordinate of a tip end 102a and 20 a rear end 102b of the cue image 102 is acquired (step 56) . The coordinate acquired here is a coordinate in a two-dimensional. coordinate system set on the plane of each image 101. In the next step S7, it is discriminated whether or not images obtained from two image sensors 37 have been processed. 25 If it is negatively discriminated, an image of the other image sensor 37 is acquired (step SS) . Then, the processing returns to the step 32. When it is affirmatively discriminated in the 34 step S7, the processing goes to the step S11 of the FIG. 10. In the step S1l of FIG. 10, a two-dimensional coordinate of the tip end 102 of the cue acquired in the step S6 is selected as a processing target. The two-dimensional coordinates exist 5 one by one relevant to each image sensor 37. By the processing of the subsequentsteps S12 toS16, a three-dimensional coordinate of typical points of the cue is computed based on a two-dimensional coordinate to be processed. Hereinafter, the processing of the steps S12 to S16 will be described with reference to FIG. 12A 10 and FIG. 12B. FIG. 12A shows a state in which a cue 45 is shot toward the simulative ball 14, wherein a three-dimensional coordinate system x-y-z is set with respect to the detection range 41. For example, when a center 14a of the simulative ball 14 is defined 15 as an origin, x-axis, y-axis, and z-axis are set in the forward/backward direction, transverse direction, and vertical direction of the game machine 1, respectively. The viewpoints VP1 and VP2 of each image sensor 37 are constant, and the three-dimensional coordinates (xl, yl, zl) and (x2, y2, z2) of 20 these viewpoints VP1 and VP2 are already known. In addition, the focal distance of each image sensor 37 is also constant. Further, the image 101 shown in FIG. 11B corresponds to, in FIG. 12A, a projected image onto scanning planes PL1 and PL2 of a predetermined size, the planes being distant from the viewpoints 25 VP1 and VP2 of each image sensor 37 by a focal distance and being orthogonal to optical axes AX1 and AX2 of each image sensor 37. In other words, each image sensor 37 scans an image obtained 35 by projecting the cue 45 onto the scanning plane PL1 and PL2 corresponding to itself, and outputs data on the scanned image. The three-dimensional coordinate of cross points CPl and CP2 between the optical axes AXl, AX2 and the scanning plane 5 PL1, PL2 can be obtained from the three-dimensional coordinate of the viewpoints VP1 and VP2 and the focal distance of each image sensor 37. Therefore, a relationship between the two-dimensional coordinate and the three-dimensional coordinate on the scanning planes PL1 and PL2 of the cross points CP1 and 10 CP2 can also be obtained in advance. Based on the relationship between the two-dimensional coordinate andthe three-dimensional coordinate on the scanning planes PLI and PL2 of the cross points CP1 and CP2, the two-dimensional coordinate of all points on the image 101 of FIG. 11B can be converted into the 15 three-dimensional coordinate in the three-dimensional coordinate system of FIG. 12A. In the processing of FIG. 10, in the case where the two-dimensional coordinate of the tip end 102a of the cue image 102 has been selected in the step Sll, the two-dimensional 20 coordinate of the tip end 102a thereof is first converted into the three-dimensional coordinate. Then, an equation expressing straight lines Ll and L2 connecting the tip end 102a and the viewpoints VP1 and VP2 each is obtained (step S12) . Next, it is judged whether or not the straight lines L1 and L2 have a 25 cross point (step S13) . When it is affirmatively judged, the three-dimensional coordinate of the cross point is determined as a three-dimensional coordinate of the tip end 45a of the cue 36 45 (step S14) . On the other hand, if it is negatively judged, a perpendicular line L3 common to two straight lines Li and L2 is obtained as shown in FIG. 12B (step SIS). Then, the three-dimensional coordinate of a middle point MP of the 5 perpendicular line L3 is determined as a three-dimensional coordinate of the tip end 45a of the cue 45 (step S16) . After the three-dimensional coordinate of the tip end 45a has been determined, the processing goes to the step S17 of FIG. 10 in which it is judged whether or not the coordinate of the rear 10 end 102b of the cue image 102 is selected as a processing target. In the case where it is negatively judged, the coordinate of the rear end 102b of the cue image 102 is selected as a processing target (step S18). Then, the processing returns to the step S12 in which the three-dimensional coordinate of the rear end 15 45b of the cue 45 corresponding to a rear end 102b is obtained. In the case where it is affirmatively judged in the step S17, the cue detection processing is terminated. As has been described above, the three-dimensional coordinate of the tip end 45a and rear end 45b of the cue 45 is obtained, whereby one cue detection 20 processing terminates. The computed three-dimensional coordinate is stored in a predetermined position of a work RAM 53 as information indicating a position of the latest cue and its direction. In addition, the image 101 and base image 100 acquired by the above processing as well are properly stored 25 in the work RAM 53. FIG. 13 and FIG, 14 are flow charts showing procedures for shot determination processing executed on a scene on which 37 a player shoots the simulative ball 14, of a variety of processing functions executed by the CPU 50 based on a game program. This processing includes processing for the player to generally determine a virtual cur ball position or shot direction by 5 utilizing operating buttons 9a to 9e (steps S21 to S30); and processing for determining the content of the shot in response to an operation for shooting the simulative ball 14 (steps S33 to S40). Hereinafter, a description will be given in order. In shot determination processing, an image obtained when 10 a virtual billiard table is seen from an upward viewpoint is displayed on a monitor 3 (step S21). In this manner, as shown in FIG. 16, for example, an image 120 obtained when a table 121 is seen from the top is displayed on the monitor 3. Then, it is discriminated whether or not there is a need to determine 15 a cue ball position (step S22) . For example, in the case of a break shot or in the case where the player's counterpart has made a fault, the player is permitted to place the cue ball at an arbitrary position on the table. Thus, it is affirmatively judged in the step S22. The term "cue ball" used here denotes 20 a virtual cue ball 122 disposed on a virtual billiard table 121 displayed on themonitor 3. While agame is executed, theposition of each ball on the table 121 is recorded in the work RAM 53, for example, and is referred to by the CPU 50 as required. In the case where it is affirmatively judged in the step 25 S22, it is judged whether or not any of the up, down, left, and right operating buttons 9b to 9e is operated to be pushed (step S23). In the case where it is affirmatively judged, theposition 38 of the cue ball on the monitor 3 is changed in the direction of the pushed buttons 9b to 9e (step S24) . Then, it is judged whether or not an OK button 9a has been operated to be pushed (step S25) . In the case where it is negatively judged in the 5 step S22, processing of the step S24 is skipped. When the OK button 9a is not operated, the processing returns to the step S23. Therefore, the player can move the position of the virtual cue ball 122 in the vertical and transverse directions in the screen by utilizing the operating buttons 9b to 9e until the 10 OK button 9a has been operated. When the player operates the OK button 9a, it is affirmatively judged in the step S25. The CPU 50 recognizes that the player has determined the current position of the cue ball 122 (step S26). The processing of the above steps S23 to 15 S26 determines the cue ball position. In the case where it is negatively judged in the step S22, this processing is skipped. After the cue ball position has been determined in the step S26, or alternatively, after it has been negatively judged in the step S22, a guide line 123 indicating a trajectory of 20 the cue ball 122 displayed on the monitor 3 is displayed on the monitor 3 (step S27) . The guide line 123 is a line indicating movement of the cue ball 122 when the cue ball 122 is shot straight toward a target ball 125 by the virtual cue 124. FIG. 16 shows a display example of the guide line 123 during a break shot. 25 In the next step S28, it is judged whether or not the left button 9d or right button 9e has been operated. In the case where either of the buttons 9d and 9e has been operated, the 39 direction of the guide line 123 is changed according to the direction of such a button (step S29) . By this processing, the player can narrow a target ball. When neither of the operating buttons 9d and 9e is operated, the step S29 is skipped. In the 5 next step S30, it is judged whether or not the OK button 9a has been operated. When it is judged that the button has not been operated, the processing returns to the step S28. When it is judged that the OK button 9a has been operated, the motor 28 is driven so that the simulative ball 14 is set at a shot position 10 (step S31) . Then, the processing goes to the step S32 of FIG. 14. The driving of the motor 28 is continued until the photo sensor 31 has been turned ON, and terminates when the photo sensor 31 is turned ON. In the step S32 of FIG. 14, the game screen displayed on 15 the monitor 3 is changed to an image 130 from the player ' s viewpoint as shown in FIG. 17. This image 130 corresponds to an image obtained when a virtual cue ball 122 is viewed slightly upwardly at the opposite side of a guide line 123. After the image has been changed, the cue detection processing (FIG. 9 and FIG. 10) 20 is started based on the image of the image sensor 37 (step S33). Subsequently, the cue detection processing is repeatedly executed in a predetermined cycle until the processing of FIG. 14 terminates. In the present embodiment, the CPU 50 executes the shot determination processing and the cue detection 25 processing in parallel by time division processing. However, microprocessors that carry out cue detection processing exclusively may be provided independent of the CPU 50. 40 In the next step S34, it is judged whether or not the left button 9d or right button 9e has been operated. In the case where either of these buttons is operated, the guide line 123 and the viewing position of the image 130 are rotated in the 5 clockwise or counterclockwise direction at the periphery of a virtual cue ball 122 (step S35). When it is negatively judged in the step S34, the step S35 is skipped. In the next step S36, it is judged whether or not the up button 9b or down button 9c hasbeenoperated. Wheneitherof these buttons has been operated, 10 the image of the monitor 3 is changed to the image 120 (FIG. 16) fromanupwardviewpoint (stepS37) , andtheprocessing returns to the step S36. In this manner, while the up button 9b or down button 9c is operated, the image 120 from the upward viewpoint is displayed on the monitor 3. In this manner, the player can 15 check the guide line 123 or the position of each ball again. When operation of the up button 9b or down button 9c is released, the processing goes to the step S38, and it is judged whether or not a first photo sensor 31 has been turned OFF. If the sensor is not turned OFF, the processing returns to the step 334. After 20 the cue detection processing has been started in the step S33, while processing of the steps S34 to S38 is repeated, the three-dimensional coordinate of the cue 45 is serially computed. Then, the cue image 124 is displayed on the image 120 or 130 based on the obtained three-dimensional coordinate. 25 - When the player shoots the simulative ball 14 by the cue 45, the simulative ball 14 falls from the shot position to the standby position. Concurrently, an output of the first photo 41 sensor 31 is changed from ON to OFF. In this manner, it is affirmatively judged in the step S38 of FIG. 14. In this case, the CPU 50 computes the shooting point of the simulative ball 14 and the shot angle thereof from the current 5 three-dimensional coordinate of the cue (step S39) . This computation result can be geometrically obtained from an equation of the simulative ball 14 in the three-dimensional coordinate system and the three-dimensional coordinate of the tip end 45a and rear end 45b of the latest cue 45 at a time when it is 10 affirmatively judged in the step S38. The shot angle is obtained as an angle in the three-dimensional coordinate system, and includes both of an angle relevant to the vertical direction and an angle relevant to the horizontal direction. When the coordinate of the cue 45 acquired at a time when a signal of 15 the first photo sensor 31 has changed is actually obtained as a coordinate after the simulative ball 14 has been shot by the cue 45 for a reason such as delay in processing, it is desirable that the shooting point and the like be specified by using the coordinate of the cue 45 at a time which is estimated as being 20 immediately before the simulative ball 14 is shot by the cue 45. After the shooting point or the like has been computed, subroutine processing for speed detection of the simulative ball 14 is executed by utilizing the first and second photo sensors 25 31 and 32 (step S40) . This subroutine processing is executed in accordance with the procedures shown in FIG. 15. First, the clocking of a time counter is started when the first photo sensor 42 31 has been turned OFF (step S51) . The time counter is provided as software. Then, it is judged whether or not the second photo sensor 32 has been turned ON (step S52) . When it is judged that the sensor has been turned ON, the time counter is stopped (step 5 S53) . Next, the clocking time of the time counter is converted to an initial speed of the simulative ball 14 (step 354). That is, the clocking time of the time counter is divided by a distance when the simulative ball 14 moves from a time when the first photo sensor 31 has been turned OFF to a time when the second 10 photo sensor 32 has been turned ON, thereby obtaining the initial speed of the simulative ball 14. In this manner, the subroutine processing is terminated, and the processing goes to the step S41 of FIG. 14. In the step S41, initial operation on the table 121 of 15 the virtual cue ball 122 is computed based on the detection result of the shooting point, shot angle, and initial speed of the simulative ball 14. This computation specifies how the cue ball 122 starts operation on the virtual table 121 in the case where a given shooting point, shot angle, and initial speed are applied 20 to the virtual cue ball 122. Then, shot determination processing is terminated by computation of this initial operation. Subsequently, movements of the cue ball 122 are serially computed with consideration for a roll resistance of the cue ball 122 or collision with another ball, and the cue ball 122 or another 25 ball on themonitor 3 is moved according to the computation result . These computation processing functions may be similar to those of a general video game. Adetaileddescription is omitted here. 43 The present invention can be carried out according to a variety of aspects without being limited to the above described embodiments . For example, the following variations can occur. (1) Either one of rotational motion of the simulative ball 5 14 around the axle of the ball axis 26 and linear motion in the axial direction of the ball axis 26 may be omitted. Instead of a structure for fixing the ball axle 26 and simulative ball 14, both of the all axis 26 and the simulative ball 14 may be linked with each other with a structure such that either of their 10 rotational motion and their linear motion is permitted. (2) In order to detect operation of the simulative ball, a variety of sensors may be used without being limited to a method utilizing the photo sensors 31 and 32. For example, an acceleration sensor is provided in the inside of the simulative 15 ball 14 or at a movable portion of the support mechanism 16, whereby it may be judged whether or not the simulative ball 14 has been shot based on the output signal or the speed (or acceleration) at which the simulative ball 14 has been shot may be detected. 20 (3) In the above described embodiments, judgment of whether or not the simulative ball has been shot, computation of a speed at which the simulative ball has been shot, and computation of virtual cue balloperation are executed by the same CPU 50, whereby the CPU 50 of the game machine 1 has also functioned as a 25 discriminating device and a speed computing device of the input device. However, a CPU functioning as a discriminating device or a speed computing device and a CPU carrying out a variety 44 of game computations such as computation of cue ball operation may be provided independently. (4) The simulative ball 14 may be linearly movable. (5) The input device according to the present invention 5 may be configured as an input device of a game machine for home use, or alternatively, as an input device of a game system utilizing a network without being limited to an example wherein the input device is configured as an input device of an arcade game machine. 10 (6) Three or more image acquiring devices such as the image sensors 37 and the like may be provided without being limited to two. (7) In order to specify the speed of the simulative ball, a variety of sensors may be used without being limited to a method 15 utilizing the photo sensors 31 and 32. For example, an acceleration sensor is provided in the inside of the simulative ball 14 or at a movable portion of the support mechanism 16, whereby it may be judged whether or not the simulative ball 14 has been shot based on the output signal or the speed (or 20 acceleration) at which the simulative ball 14 has been shot may be detected. By an image acquired from the image sensor 37, the three-dimensional coordinate of a typical point (for example, a tip end 45a) of the cue 45 is specified over at least two frames. The movement speed of the cue 45 may be computed from these 25 specification results. Alternatively, from the computation result, the speed at which the simulative ball 14 has been shot may be obtained. 45 (8) In the above described embodiment, the tip end 45a and rear end 45b of the cue 45 is specified from the image acquired at a time when the simulative ball 14 has been shot, whereby the shooting point of the simulative ball 14 or the shot angle 5 thereof has been computed. However, a time based change at the positionof the tipend45a, for example, of the cue 45 is specified from different images in time, whereby the shooting point of the simulative ball 14 or the shot angle thereof can be computed. (9) In the above embodiment, computation of the position, 10 angle, and speed at which the simulative ball has been shot and computation of virtual cue ball operation based on these computation results are executed by the same CPU 50, whereby the CPU 50 of the game machine 1 has functioned as a coordinate specifying device, an information generating device, a 15 discriminating device, and a base image updating device of the input device. However, a CPU for specifying the shooting point, shot angle and speed of the simulative ball 14 and a CPU for carrying out a variety of game computations such as computation of cue ball operation may be provided independently. That is, 20 the input device 10 according to the present invention may be provided to be commercially available in an aspect of computing and outputting at least one of the position, angle and speed of the shooting. (10) The simulative ball 14 may be linearly movable. 25 (11) The game system according to the present invention maybe configuredas agamemachine forhome use, or alternatively, a game system utilizing a network without being limited to an 46 example wherein the game system is configured as an arcade game machine. The input device according to the present invention as well may be configured as an input device of a game machine for home use, or alternatively, as an input device of a game 5 system utilizing a network without being limited to an example wherein the input device is configured as an input device for an arcade game machine. As has been describe above, according to the input device of the present invention, in the case where the simulative ball 10 has been shot in a specific direction off its core, the simulative ball rotates around a ball axis according to the shooting point or shot angle of the simulative ball, or alternatively, the simulative ball can move in the axial direction of the ball axis. At least either one of these motions is permitted, whereby the 15 feeling such that the simulative ball escapes is provided to a player, and the feeling when an actual cue ball has been shot in a variety of directions can be sufficiently reproduced. According to the billiard game system of the present invention, the three-dimensional coordinate of at least two 20 typical points of the cue is obtained based on the image acquired by an image acquiring device. This makes it possible to specify at which position and from which direction the cue comes into contact with the simulative ball. In this manner, there is no need to constrain the cue for the purpose of detection of the 25 shooting point or shot angle. In addition, there is no need to enable the simulative ball to be partially displaced or to provide a pressure sensing sensor such as a pressure film on 47 its surface in order to specify the shooting point or shot angle. Inthismanner, aconstructionofthesimulativeballis simplified, and the simulative ball can be simulated to a cue ball used in an actual billiard. Therefore, the simulative ball simulated 5 to the actual cue ball can be freely shot by the cue. Thus, the reality of game is improved, and the amusement of the game increases. The construction of the simulativeball is simplified, and there is no need to provide a mechanism for constraining the cue. The possibility that a problem occurs is lowered 10 concurrently, and system durability and reliability can be improved. In addition, according to the game input device and computer program of the present invention, the above described billiard game system can be easily configured. 48

Claims (20)

1. A billiard game system comprising: a simulative ball movably provided in a predetermined 5 direction from a predetermined shot position as an object to be shot by a player; a plurality of image acquiring devices for outputting data on images of a predetermined detection range set in a direction in which the player shoots, which are scanned from to viewpoints different from each other relevant to the simulative ball at the shot position; a coordinate specifying device for specifying a three dimensional coordinate of at least two typical points of a cue in a three-dimensional coordinate system set with 15 respect to the detection range based on data outputted from each image acquiring device; a position/angle specifying device for specifying a shooting point and a shot angle of the simulative ball based on the coordinate of the typical points of the cue specified 20 by the coordinate specifying device; a speed information detecting device for detecting information correlated with a speed of the simulative ball; a speed specifying device for specifying a speed at which the simulative ball has been shot based on information 25 detected by the speed information detecting device; and a computing device for computing an operation of a virtual cue ball to be displayed on a screen of a predetermined display unit in correspondence with the simulative ball based on the specified shooting point, 30 angle, and speed; wherein a respective one of the plurality of image acquiring devices outputs data that corresponds to a projected image onto each scanning plane different from each -49- other, the scanning planes being set in the three dimensional coordinate system, and wherein the coordinate specifying device comprises: a two-dimensional coordinate acquiring device for 5 acquiring a two-dimensional coordinate of points that correspond to the typical points of a cue image included in the image scanned by each image acquiring device; a straight line specifying device for referring to information associated with the three-dimensional coordinate 10 assigned in advance to a respective one of the viewpoints and the scanning planes, thereby converting the two dimensional coordinate of each point acquired by the two dimensional coordinate acquiring device into the three dimensional coordinate system, and then, specifying straight is lines that connect each point at which the three-dimensional coordinate has been assigned and each viewpoint corresponding to each of the scanning planes to which each of the points belongs; and a typical point coordinate determining device for 20 determining a three-dimensional coordinate of each of the typical points on the cue from a mutual relationship between the specified straight lines.

2. The billiard game system according to claim 1, comprising: 25 a simulative ball operation detecting device for detecting the presence or absence of an operation from the shot position of the simulative ball; and a discriminating device for discriminating whether or not the simulative ball has been shot, based on a detection 30 result of the simulative ball operation detecting device, wherein the position/angle specifying device specifies the shooting point and the angle based on the coordinate of -50- the cue at a time when it is discriminated that the simulative ball has been shot.

3. The billiard game system according to claim 1, wherein the typical point coordinate determining 5 device determines a three-dimensional coordinate of a cross point of at least two straight lines, or alternatively, of a middle point of a perpendicular line common to at least two straight lines as the three dimensional coordinate of each of the typical points. to

4. The billiard game system according to claim 2 or claim 3, wherein the two-dimensional coordinate acquiring device extracts the cue image from a difference between a base image corresponding to a background image when the cue 15 is excluded from the detection range and an image including the cue, and acquires a two-dimensional coordinate of at least each two points of the extracted image.

5. The billiard game system according to claim 4, wherein a respective one of the plurality of image 20 acquiring devices scans repeatedly the detection range and outputs each of the scanned image data, and wherein the two-dimensional coordinate acquiring device comprises a base image updating device for specifying at least a part of a range of the background in a latest 25 image based on a difference between the latest image and a past image, and then, replacing the base image relevant to the specified range with a content of the latest image.

6. The billiard game system according to any one of claims 1 to 5, 30 wherein the position/angle specifying device specifies a shot angle relevant to a vertical direction and a shot angle relevant to a horizontal direction, respectively.

7. The billiard game system according to claim 1 -51- wherein the speed information detecting device comprises two sensors whose outputs change according to the presence or absence of the simulative ball at a respective one of two detection positions spaced from each other with 5 respect to the predetermined direction or a member that moves together with the simulative ball, and wherein the speed specifying device detects a time interval from a time when an output signal of one of the sensors changes accompanied with movement of the simulative 1a ball to a time when an output signal of another of the sensors changes, and computes a speed at which the simulative ball has been shot based on the detection result; said system comprising: a link portion having a ball axis on which the is simulative ball is capable of being mounted; and a support portion for moveably supporting the link portion, wherein the sensors of the speed information detecting device are provided so that their outputs change depending 20 on whether or not the link portion exists at a respective one of the two detection positions set in a movement range of the link portion.

8. The billiard game system according to claim 2, wherein the simulative ball operation detecting device 25 comprises a sensor whose output changes depending on whether or not the simulative ball exists at the shot position.

9. The billiard game system according to claim 1, the billiard game system being configured as an arcade game machine comprising 30 a predetermined chassis, wherein a table portion simulating a part of a table of a billiard base is provided at the chassis; an upper face of the table portion functions as a table face; a space -52- opening forwardly of the table portion is formed by the table face and a hood covering the face; a simulative ball of the shot position is movable between the shot position and a standby position retracted to the depth of the space 5 further than the shot position; and a respective one of the plurality of image acquiring devices is disposed in the hood or under the hood in a state in which a scanning direction is oriented more downwardly than a horizontal direction.

10. A game input device comprising: 10 a simulative ball movably provided in a predetermined direction from a predetermined shot position as an object to be shot by a player; a plurality of image acquiring devices for outputting data on images of a predetermined detection range set in a 15 direction in which the player shoots, which are scanned from viewpoints different from each other relevant to the simulative ball of the shot position; a coordinate specifying device for specifying a three dimensional coordinate of at least each two typical points, 20 of a rod shaped member in a three-dimensional coordinate system set with respect to the detection range based on the data outputted from each of the image acquiring devices; and an information generating device for generating information required to specify a state in which the 25 simulative ball has been shot, based on a coordinate of the typical points of the rod shaped member specified by the coordinate specifying device; wherein a respective one of the plurality of image acquiring devices outputs data that corresponds to each 30 projected image onto scanning planes different from each other, the scanning planes being set in the three dimensional coordinate system, and wherein the coordinate specifying device comprises: -53 - a two-dimensional coordinate acquiring device for acquiring a two-dimensional coordinate of each point that corresponds to each of the typical points of an image of the rod shaped member included in the image scanned by each 5 image acquiring device; a straight line specifying device for referring to information associated with the three-dimensional coordinate assigned in advance to a respective one of the viewpoints and the scanning planes, thereby converting the two to dimensional coordinate of each point acquired by the two dimensional coordinate acquiring device into the three dimensional coordinate system, and then, specifying straight liens that connect each of the points at which the three dimensional coordinate has been assigned and each of the is viewpoints corresponding to each of the scanning planes to which each of the points belongs; and a typical point coordinate determining device for determining a three dimensional coordinate of each of the typical points on the rod shaped member from a mutual relationship between the 20 specified straight lines.

11. The game input device according to claim 10, further comprising: a speed information detecting device for detecting information correlated with a speed of the simulative ball; 25 and a speed specifying device for specifying a speed at which the simulative ball has been shot based on the information detected by the speed information detecting device, 30 wherein the information generating device generates information correlated with a shooting point of the simulative ball and a shot angle thereof. -54-

12. The game input device according to claim 10 or claim 11, comprising: a simulative ball operation detecting device for detecting an operation of the simulative ball from the shot 5 position; and a discriminating device for discriminating whether or not the simulative ball has been shot, based on a detection result of the simulative ball operation detecting device, wherein the information generating device generates 10 the information based on a coordinate of the rod shaped member at a time when it is discriminated that the simulative ball has been shot.

13. The game input device according to claim 10, wherein the typical point coordinate determining is device determines a three-dimensional coordinate of a cross point of at least two straight lines, or alternatively, a middle point of a perpendicular line common to at least two straight lines, as a three-dimensional coordinate of the typical points. 20

14. The game input device according to claim 10 or claim 13, wherein the two-dimensional point coordinate acquiring device extracts an image of the rod shaped member from a difference between a base image that corresponds to a 25 background image when the rod shaped member is excluded from the detection range and an image including the rod shaped member, and acquires a two-dimensional coordinate of at least each two points of the extracted image.

15. A game input device as claimed in claim 14, 30 wherein a respective one of the plurality of image acquiring devices outputs data on an image obtained by repeatedly scanning the detection range; and -55 - wherein the two-dimensional coordinate acquiring device comprises a base image updating device for specifying at least a part of a range of the background in a latest image based on a difference between the latest image and a 5 past image, and then, replacing the base image relevant to the specified range with a content of the latest image.

16. The game input device according to any one of claims 10 to 15, wherein the information generating device generates to information required to specify a shot angle relevant to a vertical direction and a shot angle relevant to a horizontal direction, respectively.

17. The game input device according to claim 11, wherein the speed information detecting device is comprises two sensors whose outputs change according to the presence or absence of the simulative ball at a respective one of two detection positions spaced from each other relevant to the predetermined direction or a member that moves together with the simulative ball, and 20 wherein the information generating device detects a time interval from a time when an output signal of one of the sensors changes accompanied with movement of the simulative ball to a time when an output signal of another one of the sensors changes, and then, computes a speed at 25 which the simulative ball has been shot based on the detection result; said game input device, comprising: a link portion having a ball axis on which the simulative ball is capable of being mounted, and 30 a support portion for movably supporting the link portion, wherein the sensors of the speed information detecting device are provided so that their outputs change depending -56- on whether or not the link portion exists at a respective one of the two detection positions set in a movement range of the link portion.

18. The game input device according to claim 12, 5 wherein the simulative ball operation detecting device comprises a sensor whose output changes depending on whether or not the simulative ball exists at a position where the simulative ball is to be shot by a cue.

19. The game input device according to any one of 10 claims 10 to 18, wherein the game input device is configured as an input device for a billiard game.

20. A computer program for, based on data on an image outputted from a respective one of a plurality of image acquiring devices for scanning a predetermined detection 15 range from viewpoints different from each other, recognizing a rod shaped member poked in the detection range, the computer program causing a computer to function as: a coordinate specifying device for specifying a three dimensional coordinate of at least two typical points of the 20 rod shaped member in a three-dimensional coordinate system set with respect to the detection range based on data outputted from each image acquiring device; and an information generating device for generating information required to specify a state in which a 25 predetermined target disposed in the three-dimensional coordinate system has been shot by the rod shaped member based on a coordinate of each of the typical points of the rod shaped member specified by the coordinate specifying device. 30 DATED this Fifth Day of March, 2010 Konami Corporation Patent Attorneys for the Applicant SPRUSON & FERGUSON - 57 -