Abstract:
A system for measuring the distance traveled by bodies in flight during sports events, the bodies executing trajectories having a common predetermined take-off area, and a variable landing point within a landing surface. The system includes a fixed image acquisition device positioned at a predetermined distance from the take-off area for acquiring the image of the landing surface, a recorder for recording the landing surface image at least from the moment of initiation of the flight to completion of the flight, an identifying device for identifying a landing point of the body within the landing surface, and a calculating device for calculating the distance of the landing point from the take-off area.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a system for measuring distances and trajectories of people or objects traveled in sports activities, such as athletics or golf. 
     2. Description of the Related Art 
     With reference, for example, to the athletic events of shot putting, discus, hammer and javelin throwing, long jump and triple jump, a body (defined by an implement, such as the discus, or by the athlete himself) undergoes a substantially parabolic flight between a take-off area and a landing area. The flight take-off area can be a take-off board positioned at the end of an acceleration path (as in the case of the long jump and triple jump, in which at one end of this board there is a band of yieldable material or plasticine indicator), a board, for example of circular shape (as for hammer throwing), or an acceleration track bounded by a non-passable edge (as for javelin throwing). The landing area is provided on a surface the extent of which varies according to the type of athletics event, such surface being either compact (such as for the landing of an implement) or yieldable, with sand (such as the usual pit used in the long or triple jump). 
     After the body has landed, the distance between the point of impact and the point of take-off is measured to determine the propelled distance for the body and suitably displayed on an appropriate known display unit. 
     Depending on the type of propulsion (throw or jump), such measurement can be effected principally with two different instruments, namely a tape measure or a theodolite. However, the use of these measuring devices involves various problems. For example, measurement by a tape measure is not precise because of the instability of the tape measure, which tends to become twisted. There is hence a loss of linearity of the tape measure and the possibility of an incorrect measurement. 
     Even though the use of a theodolite (for example a tachometer) enables more accurate measurement, it does not guarantee exact precision. Its use requires positioning a measurement member, for example an electronic tachometer, outside the landing surface, and positioning a reflecting element within it. The distance that the body has been thrown or has jumped is measured by triangulation between the landing point, the tachometer position point, and the starting point (which can be arbitrary or virtual, such as the center of the shot putting board) of the body undergoing the trajectory. 
     This measurement may, however, not be absolutely correct. In this respect, the use of this instrument requires a reflector element to be positioned exactly at the impact mark, and maintained perfectly perpendicular to the landing surface. In addition using a theodolite with a reflecting element positioned on a yieldable surface (of sand) inevitably makes it difficult to obtain and maintain the correct measurement position. The use of a theodolite also device that the competition judge making the measurement must be trained in its use. The instrument is also expensive. Finally, the instrument must be reset after each group of jumps or throws. 
     OBJECTS OF THE INVENTION 
     An object of this invention is therefore to provide a system for correctly measuring the propelled distance of a body in a sports event in which the body follows an aerial trajectory between a take-off area and a landing area, and immediately displaying the measured value on termination of the trajectory. 
     A further object is to enable the trajectory to be verified three-dimensionally after its termination, in order, for example, to enable it to be described or be compared with other previous trajectories or with an ideal trajectory. 
     A further object is to provide a system of the stated type that provides constant results, which always provides correct measurements, and which requires no specialization by personnel (event judges) controlling the progress of the competition. 
     A further object is to provide a system of the stated type that can be used in any event, in which a body (athlete or sports implement) jumps or is thrown (through an aerial trajectory). 
     SUMMARY OF THE INVENTION 
     The present invention measures the distance and trajectory traveled by bodies in flight during sports events such as athletics, for example a shot, a discus or javelin, or the athlete himself when executing a long jump. The bodies executing trajectories having a common predetermined take-off area, and a landing point variable within a landing surface. 
     The system of the present invention includes a fixed image acquisition device, such as a video camera for acquiring the image of the landing surface and positioned at a predetermined distance from the take-off area. Also included is a recorder, such as a digital recorder, for recording the image or the body in flight, at least from the moment of initiation of the flight to its completion. The present invention further includes a device for identifying the landing point of the body within the landing surface. This device may be, for example, a cursor movable on a calculation area matrix present on a monitor. The cursor can be positioned on the landing point of the body that has undergone the aerial trajectory. 
     The system of the present invention further includes a calculating device, such as a microprocessor, for calculating the distance of the landing point from the take-off area. Preferably, a display unit displays the result of the distance calculation. 
     Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings wherein like reference symbols refer to like parts. 
     FIG. 1 is a top view of a surface for performing athletics events in which distances are measured by the system of the invention; 
     FIG. 2 is a top view of a surface for the long jump in which measurements are taken by the system of the invention; 
     FIG. 3 is a top view of a surface for a hammer throwing event in which measurements are taken by the system of the invention; 
     FIG. 4 is a schematic block diagram of the system of the invention; 
     FIG. 5 is a schematic block diagram of the system of the invention used in a triple jump event; 
     FIG. 6 is a block diagram of a phase of execution of the system of the invention; 
     FIG. 7 is a flow diagram showing the execution of a part of the phase of execution of FIG. 6; 
     FIG. 8 is a flow diagram showing the execution of a different part of the phase of execution of FIG. 6; 
     FIG. 9 is a schematic video representation of a sports event in which the system of the invention is used; and 
     FIG. 10 is a schematic view of a competition field in which an implement or body effects a trajectory which is measured in accordance with the invention. 
    
    
     DETAILED DESCRIPTION 
     With reference to FIG. 1, a surface on which athletic events take place is indicated overall by  1 . It includes acceleration tracks  2  for the long jump and triple jump, acceleration tracks  3  for javelin throwing, footboards  4  for throwing the discus and hammer, and footboards  5  for shot putting. Dashed lines indicate the landing surfaces ( 3 A,  4 A and  5 A respectively) for the implements thrown. The pits (containing sand) in which the athletes land after the long jump and triple jump are indicated by  2 A. 
     A structure to the side of the surface  1  is indicated by  6 . The structure  6  can be a raised bank to the side of a usual athletic track  7  or contain stands for the public watching the sports events. 
     According to the invention, a system  10  (FIGS. 2-5) is provided to determine the extent, distance or trajectory of the flight undergone by a sports implement (for example a discus or javelin) or by an athlete who has jumped (for example a long jump). 
     Specifically, the system  10  comprises at least one video camera  11  (or equivalent image acquisition device, such as an infrared sensor or the like) located in a fixed position on one side of the landing surface  2 A,  3 A,  4 A or  5 A. The video camera  11  can be positioned close to this surface, as in the case of a long jump pit in which the video camera is positioned for example between 1 and 3 meters from this pit, or at a slightly greater distance, as in the case of the landing surface  5 A in shot putting events in which the video camera is positioned for example between 5 and 10 meters or more from this surface, or at a great distance from it as in the case of the surfaces  3 A and  4 A at which javelin throwing, discus throwing or shot putting events occur. In this case, the video camera  11  is positioned preferably between 20 and 40 meters or more from the surface. In all cases the lens  12  of the video camera has such an aperture or such a shape as to capture a wide and adequate extent of the landing surface at which the image acquisition device is aimed. This extent is preferably chosen on the basis of data relative to throw or jump trajectories of the athletes participating in the event. For example in the case of the long jump, if the athletes participating in the event are accredited with jumps all lying within the range of 7 to 9 meters, the video camera is aimed at a distance of 8 meters from the usual jumping footboard (indicated by  13  in FIGS. 2 and 5) and has a lens aperture such as to embrace that part of the pit distant 6.5 to 9.5 meters from the footboard  13 . 
     Similar conditions apply in identifying the landing areas of the surfaces  3 A,  4 A and  5 A. As these latter have a wide extension, preferably two spaced-apart video cameras are used to acquire the image (as shown in FIGS.  1  and  3 ). 
     The image acquisition device (i.e., each video camera  11 ) is connected to an image processing unit to enable the propelled distance of the body on landing to be measured. This image processing unit, shown generally as  15  in the figures, may comprise one or more image recorders, ports for receiving the recorded images, an image conversion device, and a personal computer (PC) or microprocessor suitably programmed to perform image and data processing. 
     With reference to FIGS. 2,  4 , and  5 , these show an embodiment of the invention used for measuring a long jump and triple jump. In the example, a first video camera  11  is positioned in correspondence with the pit or landing surface  2 A, and another video camera  11 A is positioned in correspondence with the jumping footboard  13  to record the exact point at which the athlete&#39;s foot separates from it. This is useful for measuring the true length of the athlete&#39;s jump. This measurement cannot be obtained using the measuring device currently used in sports activities. 
     The video camera  11  is positioned at a known distance K from the footboard (acting as an index line) and is connected to an image recording member  16  of the image processing unit  15 . The image recording member(s), shown in FIGS. 4 and 5, are preferably of a digital type. The video camera  11 A is connected to a similar digital video-recorder  16 A, as shown in FIG. 5, for example. In the case of a triple jump, an additional two video cameras  11 B and  11 C are provided to acquire the image of landing areas  2 B and  2 C between the pit  2 A and the footboard  13 , the athlete landing on such areas during the triple jump. The video cameras  11 B and  11 C are also connected to corresponding video-recorders (preferably digital)  16 B and  16 C. All the video-recorders provided are mutually synchronized to the same time base. 
     Each image recording device  16 ,  16 A,  16 B and  16 C is connected to image processing device  18  that retransforms the recorded data into signals for conversion into images by image conversion device  19 , which is connected to a monitor  20 . Referring to FIG. 4, the image processing device  18  includes a video card  18 A connected to one or more recording devices via its own serial port and a video signal mixer or selector  18 B also connected via a serial port  23  to the corresponding recording device(s). The image conversion device  19  is an image converter connected to the monitor  20 . 
     The devices  18  and  19  are connected to a microprocessor unit  24  (FIG. 5) that connects to the serial communication ports  23  and through which the microprocessor controls the video-recorders  16 ,  16 A,  16 B. The microprocessor unit  24  is connected to a keyboard  25 , to a mouse  26 , to the monitor  20 , and to a display unit  40 . 
     The microprocessor unit  24  can also be provided with an optical aberration compensation device (not shown), for example a digital view-finder, which can modify the parameters and/or the images of the landing surface from which the image is acquired so as not to be affected by any light or light-dark zone reverberations. 
     The microprocessor unit  24  is connected via an output  30  to display unit  40  that displays the measurement results and/or to a television control room connected to a telecommunication or remote image transmission network by which images of the athletics event are fed into a television circuit together with the data relative to the measurements effected. These latter can be directly displayed by suitable known video techniques directly on the images originating from one of the television cameras filming the event. 
     The method of performing the measurement of the present invention is described with reference to FIGS. 6 to  9 . 
     FIG. 6 shows a block diagram flow of the method for measuring the propelled distance of the body that has undergone an aerial trajectory between a take-off area (for example the footboard  13 ) and the landing area within the surface  2 A. 
     An operator operates the keyboard  25  or the mouse  26  (block  60 , FIG. 6) to select the type of event (jump or throw) that is to be measured. The operator then selects (block  61 ) the method of operating the system, i.e., whether in setting-up mode (shown in FIG. 7) or in live distance measurement mode, i.e., measurement during an event (FIG.  8 ). Once the mode is selected, the operator initiates execution of the mode (block  62 ) to achieve the desired setting-up or measurement. This mode execution is also described in FIGS. 7 and 8. The procedure then terminates (block  63 ). 
     Specifically, the setting-up mode (see FIG. 7) comprises selecting the number of documents present in a memory  42  of the microprocessor unit  24 , (block  71 , FIG.  7 ). These documents refer, for example, to a plurality of images of the long jump pit  2 A (shown on the monitor  20  as represented in FIG. 9) after a jump. The stored image represents the impression  29  that is formed on the pit  2 A after the athlete has landed. 
     A decision is then made (block  72 ) whether a real or a virtual measurement of the jump is to be calculated, or if the distance from the point of landing of the athlete from the index line is to be calculated, or if the distance between the landing point and the actual point of separation of the athlete from the footboard is to be calculated. 
     If the measurement is to be virtual, the setting-up mode updates the number of documents in the memory by increasing it by one (block  73 ). If the calculation is to be real, it chooses the document already in the memory (block  74 ) and sets it up (block  75 ). Setting-up comprises enclosing the landing area present on the surface or pit  2 A within a matrix, for example of quadrilateral form  31  created on the monitor  20  by using the mouse  26  or a usual line selection algorithm fed into the microprocessor unit  24 . The quadrilateral has two end sides  32  and  33  parallel to each other and to the impassable jump line located on the jumping footboard  13  (the line is indicated by  13 A in FIGS.  2  and  5 ). The distance of the line  13 A from these sides is defined and stored in memory  42  of the microprocessor unit  24 . In the described embodiment of the invention, the area of the quadrilateral or matrix  31  is divided into several bands or lines  36  parallel to each other and to the sides  32  and  33 , of known width (measured along the longitudinal axis Z of the landing surface). Each band width is stored in the memory of the unit  24  to identify the distance between the side  36 A of each band and the side  32 . The matrix  31  could also have another form, for example in rows and columns or by only the end lines  32  and  33 . 
     Having done this, a check is made to determine whether further setting-up is required (block  76 ), after which the procedure returns to block  74  or the setting up terminates (block  77 ). 
     If instead the measurement is to be real, i.e., the measurement is to be calculated during a jumping event (for example), the procedure is as follows. 
     At the commencement of the jump, during the athlete&#39;s warm-up, the recording devices  16 ,  16 A,  16 B,  16 C and  16 D are activated, and in particular the device  16  associated with the video camera positioned to the side of the pit  2 A (block  80  of FIG.  8 ). When the jump has been made, the procedure halts (block  81 ) recording of the image acquired by the video camera or video cameras (for example the video camera  11  positioned at the pit  2 A). The image is displayed on the monitor as a still image (block  82 ). Then, using a vertical cursor  39  (described hereinafter), the band  36  in which the near end  29 A of the impression  29  (closer to the footboard  13 ) lies is identified (block  83 ). The vertical cursor  39 , which is movable on the monitor  20  parallel to the sides  32  and  33  and to each band side  36 A is positioned on this end  29 A. Block  84  then verifies that the selected band does not have to be corrected (i.e., that the end  29 A lies inside the quadrilateral  31 ), The microprocessor  24  then proceeds to calculate the measurement (block  85 ) by adding the pre-stored distance between the side  32  and the line  13 A to the distance between the end  29 A (identified by the line  39 ) and the side  32 . The microprocessor unit  24 , using calculation algorithms that will be readily apparent to one having ordinary skill in the programming art, executes this calculation. This calculation yields the distance of the end  29 A or landing point from the take-off area (line  13 A). 
     All this is achieved in real time within a few seconds (2-4 seconds) from the moment in which the athlete lands. 
     The procedure then checks whether another measurement is to be effected (block  86 ), in which case it returns to block  82 . If the event has terminated it leaves this described mode of operation (block  87 ). 
     The invention provides certainty of measurement, which is effected by a data processing device operated by knowledgeable personnel, without the measurement being made by competition judges who are hence freed from the commitments of this operation and the risk of error. 
     The measurement is made without the need for any presence on the competition ground and without any possibility of the measurement being influenced by such presence. 
     The mode of operation for measuring a long jump has been described. A throw of an implement (discus, shot, hammer or javelin) or a triple jump can be likewise measured using the same mode of operation, and following the schemes of FIGS. 6,  7  and  8 . 
     In this respect it should be noted that using the system of the invention, by positioning the video cameras  11 A,  11 B and  11 C beside the areas  2 B,  2 C of the track  2  and at the footboard  13 , the length of the intermediate jumps of a triple jump athlete can be measured. The methods for obtaining these measurements is identical to those already described with reference to FIGS. 6,  7  and  8  and are therefore not further described. 
     Measurement of the intermediate jumps is not possible with the state of the art instruments used up to the present time for measuring distances in athletics. Such a measurement can enable an athlete to obtain data relative to these intermediate jumps and hence be able to achieve improvement (for example by making intermediate jumps of greater or lesser length in order to effect the final jump in such a manner as to land as far as possible from the footboard  13 ). By knowing the intermediate jumps of their adversaries, an athlete can also understand their competition strategy and possibly adapt it if this strategy leads to victory. 
     Moreover, the system of the invention as used to calculate the thrown distance of a javelin or discus also enables its flight stability to be verified, enables any wind force influencing the implements to be detected (which, for example, may lead to a poor result), and enables the manner of throwing to be determined (again to enable the athlete to improve his technique or to know the throwing techniques of his adversaries). This is achieved by virtue of the use of video cameras with image recording systems and three-dimensional processing. The use of the invention for this processing is illustrated in FIG. 10, which shows an event site  101 , an implement  102 , and an implement trajectory  103 . The invention can check correspondence between this trajectory and an ideal trajectory  104 , to achieve a throw leading to victory or medal result. 
     A particular embodiment of the invention applied to athletics has been described. The invention is however applicable to other sports. For example, the invention can be applied to golf to measure the distance and trajectory of a shot in order to examine the effectiveness of this shot, to enable the athlete to know the best tactics to use in attaining good results in a competition, and to understand the performance of the implements used (golf club, ball). 
     While the invention has been described in conjunction with several specific embodiments, it is evident to those skilled in the art that many further alternatives, modifications and variations will be apparent in light of the foregoing description. Thus, the invention described herein is intended to embrace all such alternatives, modifications, applications and variations as may fall within the spirit and scope of the appended claims.