A METHOD OF DETERMINING PRESSURE INDEX

Abstract: The invention relates to a method of determining pressure index in a game. The game takes place in a sports field provided with at least one goal. The game also comprises at least two teams and at least one game tool. Each team consists of at least one player. The method also uses means for determining the positions of players and game tool. The proposed method is characterised in that the determination of positions is transmitted to a computer, following which the pressure index on each player (X1) in control of the game tool is calculated by computer as the sum of pressure from at least one opponent (M1); and wherein is included at least one function of distance and time between at least one opponent (M1) and the player (X1), wherein the time constitutes at least the time during which the player (X1) is in possession of the game tool. Hereby a quantifiable and unambiguous measure of the pressure index on a player (X1) is obtained by a method that is independent of a human discretion by an expert, ie an objective and reproducible method.

Description: A METHOD OF DETERMINING PRESSURE INDEX The invention relates to a method of determining pressure index in a game. The game takes place in a sports field and the sports field is provided with at least one goal. The game also comprises at least two teams and at least one game tool. Each team consists of at least one player. The method also uses means of determining the positions of players and game tool. The intensity of a game expresses the magnitude of the pressure exerted on the participants of the game. The larger the pressure exerted on a participant, the more difficult it is for the individual player to exercise the game. A pressure index is therefore able to tell at which level a game is being exercised. Today, the intensity of a game is measured by experts in the form of former or present players, coaches or other with comprehensive knowledge of the game in question performing an assessment after having watched the game. This assessment is based on subjective considerations that are influenced by the relevant expert's technical background with the game and takes its start- ing point in an overall hunch of the course of the game. A subjective assessment is therefore not always in accordance with the factual intensity. This subjective assessment renders comparisons of the intensity of a game over time or across national leagues untrustworthy. A more objective method would render such comparisons trustworthy. The subjective assessment makes the foundation of the analysis unreliable and the understanding of the game and the possibilities of developing the game become uncertain. An objective determination of the intensity strengthens the foundation of the analysis and thus enhances the understanding of the game and its possibilities of development. FR patent application No. 2711069 teaches a method for detecting offside situations in football that involves detection of the position of each player (1 through 11 and 21 through 31) on the sports field, whereby a triggering signal is emitted when an offside situation occurs, the position of the forwardmost player of the attacking team is compared to the positions of the two rear- wardmost players of the defending team, and a signal is generated in the event of a positive comparison when the triggering signal is emitted. However, the method is restricted to detecting offside situations and is not capable of calculating a measure of the pressure index on the players. FR patent application No. 2726370 teaches a position determination system having a tracking system that includes very small radio emitters placed in the ball and on each player and at least three receivers to determine each position in 3-D. The emitters' range determines the number of receivers required to cover the whole sports field. Alternatively one or more cameras with digital image control can determine the positions. Information is conveyed to a processor that analyses it and stores the result, eg for providing statistics, match state and tactic. The information can also be used later on for training purposes. The system also informs a referee in real time about any controversial situation, by visual or sound channels. However FR 2726370 does not define how the statistic results are determined and, likewise, it is not defined either how the tactics are determined. Albeit it has been taken into account al which point in time the measurements occur, it is not very specific, however, and absolutely not when it comes to tactics. It has not been taken into account, among which players the meas- urements are taken, or between which players the distance is to be determined. Besides, the system is not able to incorporate the speed of the players in the calculations, either. Finally, choice of calculation method is not specified. FR patent application No. 2753633 teaches a method that involves continually and remotely monitoring the positions of the players and the ball to the nearest centimetre by use of a refresh rate of less than 10ms. The position signals are transmitted to a computer and to the referee and are used to determine the positions of the players from both teams and the ball in real time. This information allows the referee to make appropriate decisions, eg when a corner kick should be awarded. Position finding is performed by use of a radio position finder or a high resolution and high definition, very short carrier radar. However, the method is limited to the detection of offside situations and is not capable of calculating a measure for the pressure index on the players. International patent application No. WO 98/37932 discloses a radio fre- quency positioning system that determines identity and positional data of numerous objects. The system includes a plurality of spread spectrum radio transceivers where at least one transceiver is positioned on each of the numerous objects. At least three radio transceivers transmit to and receive signals from the radio transceivers., A signal processor is coupled to the radio transceivers and determines the identity and the positional data of the objects. However, the system merely focuses on the tracking of objects, and a method of calculating a measure for the pressure index on the players is not included. It is the object of the invention to provide a method of obtaining a pressure index for determining the intensity of eg a football game across sports fields of different dimensions. This can be obtained by the determination of positions being transmitted to a computer, following which the pressure index for any player being in control of the game tool is calculated by computer as the sum of pressure from at least one opponent, and wherein is incorporated at least one function of dis- tance and time between at least one opponent and the player, where time constitutes at least the time lapsing from the point where the player receives the game tool until the player is no longer in possession of the game tool. Hereby it is possible to obtain a quantifiable and unambiguous measurement of the pressure index on a player by a method that is independent of a human discretion from an expert, ie an objective and reproducible method. 5 The pressure exerted by each opponent can be determined by a computer calculation wherein the function of distance and time constitutes the speed of an opponent. Hereby the pressure can also be calculated by computer on the basis of the l o speed of the opponents. The pressure from each opponent can be determined by a computer calculation, wherein a function of speed and time constitutes the acceleration of an opponent. 15 Hereby the pressure can also be calculated by computer on the basis of the acceleration of the opponents. The pressure from each opponent can be determined by a computer calcula- 20 tion wherein at least the distance between an opponent and the game tool is involved. In this manner the pressure can be determined in relation to the game tool. 25 The pressure from each opponent can be determined by the time lapsed from the point when the game tool is transmitted in the direction of the player until the player is in possession of the game tool being included in a computerised calculation of a pressure index. 30 Hereby it is possible to determine a pressure index containing the previous pressure. The pressure from an opponent can be calculated by computer as an average of the difference between the actual distance to the opponent and the ideal distance of the opponent relative to the player during the time that lapses from the game tool is transmitted in the direction of the player until the player comes into possession of the game tool plus the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player comes into possession of the game tool until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. Hereby it is made possible to determine the pressure index based on the distance alone. The pressure from an opponent can be calculated by computer as an average of the speed of the opponent in the direction of the player during the time that lapses from the game tool is transmitted in the direction of the player until the player comes into possession of the game tool, plus the speed of the opponent in the direction of the game tool during the time that lapses from the player comes into possession of the game tool until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, whereby the constant is an expression of the pressure significance of an opponent. Hereby it is possible to determine the pressure index based on the speed alone. The pressure from an opponent can be calculated by computer as an average of the reciprocal value of the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the player during the time that lapses from the game tool is transmitted in the direction of the player until the player comes into possession of the game tool, plus the reciprocal value of the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player comes into possession of the game tool until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. Hereby it is made possible to determine the pressure index for each individ- 5 ual opponent, wherein the opponent's significance to the pressure is implicitly weighted in the distance between the actual position and the ideal position of the opponent. The pressure from an opponent can be calculated by computer as an aver- o age of the speed of the opponent in the direction of the player divided by the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the player during the time that lapses from the game tool is transmitted in the direction of the player until the player comes into possession of the game tool, plus the speed of the opponent in 5 the direction of the game tool divided by the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player comes into possession of the game tool until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, where the constant o is an expression of the pressure significance of an opponent. Hereby it is possible to determine the pressure index for each individual opponent, where the significance of the opponent to the pressure is implicitly weighted in the distance between the actual position of the opponent and the 5 ideal position and simultaneously the significance of the speed is included. The pressure from a rearmost opponent, who is different from the goalkeeper, can be calculated by computer as an average of the speed of the rearmost opponent divided by the difference between the component for the 0 actual distance of the rearmost opponent to the game tool in the longitudinal direction of the sports field and the component for the ideal distance of the rearmost opponent relative to the game tool in the longitudinal direction of the sports field during the time that lapses from the game tool is transmitted to the player until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of the rearmost opponent. Hereby it is possible to determine the pressure index for the area on the sports field that is available to the team featuring the player in control of the game tool, since participants of the team featuring the player in control of the game tool is eg in an offside position in the area behind the rearmost opponent. The pressure from a rearmost opponent who is different from the goalkeeper can be calculated by computer as an average of the speed of the rearmost opponent divided by the difference between the actual distance of the rearmost opponent in the longitudinal direction of the sports field to the goal line and the maximal pressure distance of the rearmost opponent during the time that lapses from the game tool is transmitted to the player until the player is no longer in possession of the game tool, and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of the rearmost opponent. Hereby it is possible to determine the pressure index for that area of the sports field that is available to the team featuring the player in control of the game tool, and to implicitly weight the significance of the rearmost opponent by the maximal pressure distance of the rearmost opponent. The sum of pressure from at least one opponent and maximally an entire team of opponents can be corrected for the size of a sports field by means of a correction factor, where the correction factor constitutes the sum of 1 and a fraction having a numerator that is the maximal area of a sports field minus the product of the actual width of a sports field and the actual length of a sports field, and the fraction has a denominator that is the maximal area of the sports field, where the maximal area of the sports field is the maximal length of a sports field multiplied by the maximal width of a sports field. Hereby an increment correction of the pressure index for the size of the sports field is enabled, which is crucial if a pressure index is to be compared across sports fields of different sizes. The sum of pressure from at least one opponent and maximally an entire team of opponents can be corrected for the size of a sports field by means of a correction factor, where the correction factor constitutes the difference between 1 and a fraction having a numerator that is the maximal area of a sports field minus the product of the actual width of a sports field and the ac- tual length of a sports field, and the fraction has a denominator that is the maximal area of the sports filed, where the maximal area of the sports field is the maximal length of a sports field multiplied by the maximal width of a sports field. Hereby a decrement correction of the pressure index for the size of the sports field is enabled, provided the pressure index is determined according to standard, which is important if a pressure index is to be compared across sports fields of different sizes. The pressure index on a player in possession of the game tool can be calculated by computer as the average of the pressure from at least one of the opponents and maximally an entire team of opponents multiplied by a correction factor for the size of the sports field. Hereby it is possible to determine a pressure index for the average pressure on a player. A total pressure index can be calculated by computer by an average of continuous measurements of a pressure index on any player in possession of the game tool. Hereby it is possible to obtain information on a total average pressure index over a protracted period of time. A total pressure index can be calculated by a sum of continuous measurements of a pressure index on any player in possession of the game tool. Hereby it is possible to obtain information about a total summated pressure index over a protracted period of time. The number of goals can be two and the number of game tools can be one and the number of teams can be two and each team can typically consist of eleven players and the rearmost opponent is different from a goalkeeper. Hereby delimitations are obtained for the method of determining pressure index that make the method useful for sports such as eg football. The method of determining pressure index can be used eg for one of the sports: football, handball, basketball, ice hockey, and American football. Hereby a reliable method is obtained of determining pressure index and which is independent of a human discretion by an expert, ie an objective and reproducible method for the sports: football, handball, basketball, ice hockey, and American football. Collection of data for determining the position of the individual player and the position of the individual opponent and the position of game tools can be de- termined eg by means of video monitoring equipment. Hereby a reliable position determination is obtained by means of existing monitoring equipment on eg large-scale football stadiums. Collection of data for determining the position of the individual player and the position of the individual opponent and the position of game tools can be determined eg by means of transmitters mounted on the individual player and transmitters mounted on the individual opponent and transmitters mounted on the game tools and at least one signal receiver located around the sports field. Hereby reliable position determination is obtained by means of monitoring equipment that is capable of determining the position automatically, thereby rendering manual position determination redundant. Collection of data for determining the position of the individual player and the position of the individual opponent and the position of game tools can be de- termined eg visually by monitoring performed by an expert. Hereby it is made possible to use the method of determining pressure index on eg football fields that do not have monitoring equipment or signal transmitters at their disposal. The pressure index can eg be calculated automatically by means of calculation equipment. Hereby a quick and reliable calculation method is obtained, without risk of calculation errors due to human errors. For instance, the pressure index can be calculated manually. Hereby it is possible to calculate pressure index on eg football fields that do not have calculation equipment at their disposal. The invention will now be described in further detail with reference to the accompanying figures, wherein Figure 1 shows a pressure situation in which the pressure index on a player is calculated on the basis of the most proximate opponent; and Figure 2 shows a pressure situation in which the game tool is being transmitted in the direction of the player, where the pressure index on a player is cal- culated on the basis of the three most proximate opponents and a rearmost opponent, and where the sports field is equipped with video monitoring equipment; and Figure 3 shows a pressure situation in which the pressure index on a player in possession of the game tool is calculated on the basis of the three most proximate opponents and a rearmost opponent; Figure 4 is an expression of the pressure from an opponent based on the distance between opponent and player; and Figure 5 is an expression of the pressure from an opponent based on the speed of the opponent; and Figure 6 is an expression of the pressure from an opponent based on the distance including the time that lapses from the game tool is transmitted in the direction of the player until the player ends his contact with the game tool; and Figure 7 is an expression of the pressure from an opponent based on the speed including the time that lapses from the game tool is transmitted in the direction of the player until the player ends his contact with the game tool; and Figure 8 is a standardized expression of the pressure from an opponent based on the distance including the time that lapses from the game tool is transmitted in the direction of the player until the player ends his contact with the game tool; and Figure 9 is an expression of the pressure from an opponent based on the distance and speed including the time that lapses from the game tool is transmitted in the direction of the layer until the player ends his contact with the game tool; and Figure 10 is an expression of the pressure from a rearmost opponent; and Figure 11 is an expression of the ideal distance between the rearmost opponent and the game tool; and Figure 12 is a second expression of the pressure from a rearmost opponent; and Figure 13 is an expression of an increment correction factor for the actual area of the sports field; and Figure 14 is an expression of a decrement correction factor for the actual area of the sports field; and Figure 15 is an expression of the pressure on a player based on the distance, where the pressure index is calculated on the basis of an opponent, corrected by an increment correction factor for the size of the sports field; and Figure 16 is an expression of the pressure on a player based on the speed, wherein the pressure index is calculated on the basis of the two most proximate opponents, and wherein the pressure index is corrected by a decrement correction factor for the size of the sports field; and Figure 17 is a standardized expression of the pressure on a player based on the distance, where the pressure index is calculated on the basis of the most proximate two opponents and a rearmost opponent, and wherein the pressure index is corrected by a decrement correction factor for the size of the sports field; and Figure 18 is an expression of the pressure on a player based on the distance and speed, where the pressure index is calculated on the basis of the three most proximate opponents and a rearmost opponent, and wherein the pressure index is corrected by a decrement correction factor for the size of the sports field; and Figure 19 is an expression of the pressure on a player based on the distance and speed, where the pressure index is calculated on the basis of the average of the pressure from the three most proximate opponents and a rearmost opponent, and wherein the pressure index is corrected by a decrement correction factor for the size of the sports field. In Figure 1 a player (Xi) is shown on a sports field having the width B and the length L. A goal line is located at the top of the figure, whereas a back line is located at the bottom. The pressure index is calculated on the basis of the most proximate opponents (M1 ). ai is the distance between the actual position of the opponent (M1 ) and the ideal position of the opponent (M1 ) that is expressed by the difference between the distance a M i of the opponent (M1 ) to the player X-i, and the ideal distance idai of the opponent (M1 ) to the player Xi. Si S 2 S 3 are signal receivers and C is a computer. Figure 2 depicts a point in time when the player (Xo) transmits the game tool to a player (Xi) on a sports field having the width B and the length L. A goal line is located at the top of the figure, whereas a back line is located at the bottom. The pressure index is calculated on the basis of the three most proximate opponents (M1 , M2, M3) and a rearmost opponent (Mb), ai is the distance between the actual position of the opponent (M1 ) and the ideal position of the opponent (M1 ) that is expressed by the difference between the distance a M i of the opponent (M1 ) to the player Xi and the ideal distance idai of the opponent (M1 ) to the player Xi. as is a component in the longitudinal direction of the sports field of the distance between the actual position of the rearmost opponent (Mb) and the ideal position of the rearmost opponent (Mb) that is expressed by the difference between the distance component (a B M b ) of the rearmost opponent to the game tool in the longitudinal direction and the ideal-distance component (ida BM t > ) of the rearmost opponent (Mb) in the longitudinal direction. a Mb is the distance between the maximal pressure position of the rearmost opponent (Mb) and the actual position of the rearmost opponent expressed by the difference between the distance between the maximal pressure position of the rearmost opponent and the goal line aMbmax and the distance between the actual position of the rearmost opponent (Mb) and the goal line a M bma. a B a is the distance in the longitudinal direction between the game tool and the goal line. Six monitoring cameras 1 ,2,3,4,5,6 can be seen around the sports field as well as a computer C. Figure 3 depicts a point in time when the player Xi is in possession of the game tool. A goal line is located at the top of the figure, whereas a back line is located at the bottom. The pressure index is calculated on the basis of the three most proximate opponents (M1 , M2, M3) and a rearmost opponent (Mb). aeι is the distance between the actual position of the opponent (M1 ) and the ideal position of the opponent (M1 ) that is expressed by the difference between the distance a B i of the opponent (M1 ) to the game tool, and the ideal distance ida B1 of the opponent (M1 ) to the game tool. a B is the component in the longitudinal direction of the sports field of the distance between the actual position of the rearmost opponent (Mb) and the ideal position of the rearmost opponent (Mb) that is expressed by the difference between the distance component (a BMb ) of the rearmost opponent (Mb) to the game tool in the longitudinal direction, and the ideal-distance component (ida B Mb) of the rearmost opponent (Mb) in the longitudinal direction. a b is the distance be- tween the maximal pressure situation of the rearmost opponent (Mb) and the actual position of the rearmost opponent expressed by the difference between the distance in the longitudinal direction between the maximal pressure position of the rearmost opponent and the goal line (a Mb max) and the distance in the longitudinal direction between the actual position of the rearmost opponent (Mb) and the goal line (a M bma). a Bma is the distance in the longitudinal direction between the game tool and the goal line. It is decisive to the extent of a pressure exerted on the player (Xi) in possession of the game tool how much time he has to perform his action within a delimited area. Thus, the pressure is increased if area and time are reduced. Determining for the pressure on the player (Xi) in possession of the game tool is the time it takes an opponent to reduce the area that the player (Xi) in possession of the game tool has at his disposal for exercising his action. Decisive for this is the speed of the opponent in the direction of the player (X-i) and the distance of the opponent to the player (X-i) (a more precise index can be obtained by considering the speed and distance to the game tool). Since a optimal pressure begins when the game tool is transmitted in the direction of the player Xi the contribution from the preceding pressure can be calculated by considering the time that lapses from the point in time when the ball is transmitted towards the player Xi and until the player receives the ball. Determination of the average speed and average distance for each of the three opponents M1 , M2 and M3 for the time during which the player is in possession of the game tool makes it possible to obtain two pressure indexes for each of the three opponents. This makes it possible to study how the composition within the pressure is built. The pressure in the transmission phase (the game tool is transmitted in the direction of the player) can be studied. This makes it possible to study the composition of the preceding pressure. Since the connection between the pressure intensity and such pressure index is negatively correlated, ie the more intensive the pressure, the lower the pressure index, this means that the pressure index must be corrected for an increment correction factor for the size of the sports field. Thus, a small-size sports field increases the pressure index more than a large-size sports field (It is easier to obtain a low pressure index on a small sports field). The total pressure from the three opponents (M1 , M2 and M3) most proximate the player Xi plus the rearmost opponent (Mb) can also be studied. Since an intensive pressure game requires that the opponents (M1 , M2 and M3) back each other up, this means that the most ideal location for each in- dividual opponent will not be as close to the ball as possible, but rather displaced. It follows that it is necessary to determine ideal distances to the player (Xi) in possession of the game tool for each individual opponent in order to be able to determine whether the pressure is intensive. If an ideal distance is determined for the opponents (M1 , M2, M3) relative to the player (Xi) in possession of the game tool, it will be possible to determine to which extent the pressure is intensive. The faster the individual opponents (M1 , M2, M3) are located within the ideal distance to the player X^ with the game tool, the more intensive is the pressure. It follows from this that an expression of the pressure intensity can be determined by considering the average dis- tances between the actual locations of opponent M1 , M2 and M3, respectively, and their respective ideal positions during the time, when the player (Xi) is in possession of the game tool. The larger the area available for a team to play on, the smaller is the pressure to which the team is exposed. The area available to a team to play on can be determined by looking at the location of the rearmost opponent (Mb). The closer the rearmost opponent (Mb) is located to the centre line, the smaller area is available for the team to play on, and the more pressure is exerted on the team featuring the player (Xi). Determination of the average distance between the actual position and the ideal position of the rearmost player yields an expression of the pressure from the rearmost opponent (Mb). The ideal distance for the rearmost opponent (Mb) will vary in accordance with the location of the game tool on the sports field. The closer the player (Xi) is to the back line, the smaller is the ideal distance between the player (X-i) and the rearmost opponent (Mb). Ad- ditionally, the players contribute differently to a pressure. The opponent that contributes the most to the pressure on the player (Xi) in possession of the game tool is the opponent (M1 ) located most proximate to the player Xi. Then second comes the opponent M2 who is located in the closest-but-one position relative to the player Xi, and thirdly in the closest-but-two position the opponent, M3. This fact necessitates a weighting of the significance of the player to the pressure (Vi, V 2 , V 3 and V B ). Since the connection between the pressure intensity and the pressure index is negatively correlated, an increment correction facture is used herein for the size of the sports field. By study of the total pressure from the opponents, M1 , M2, M3 and Mb, when the ideal distance is set to be equal to zero, it is obtained that the pressure from the opponents (M1 , M2, M3) is calculated on the basis of the actual distance to the player X or the game tool. By using a standardized expression of the pressure by the reciprocal value of the average distance for each of the three opponents, the weighting of the individual opponent is implicitly stated. If the pressure from the rearmost opponent (Mb) is measured by the reciprocal value of the average distance to the maximal pressure distance (can be calculated as the average across several different teams of the smallest distance to the goal line for the rearmost opponent in a game), the weighting of the rearmost opponent (Mb) is also given implicitly. Since the weighting is given implicitly, the constants Vi, V 2 , V 3 and V will be equal to one. The advantage of a standardized approach is that the pressures from the individual opponents are expressed simultaneously with the weighting, the weighting taking its starting point in the distance to the player Xi or the game tool. Since the connection between the pressure intensity and the pressure index is in this case positively correlated, ie the more intensive the pressure, the higher the pressure index, it means that the pressure index must be corrected for a decrement correction factor for the size of the sports field. Thus, a small-size sports field reduces the pressure index more than a large-size sports field (it is easier to obtain a higher pressure index on a small sports field). The pressure index can also be determined by the average pressure from the three most proximate opponents (M1 , M2 and M3) alone. This pressure index will tell how solid the pressure against the player is. The pressure index must in this case be corrected for an increment correction factor for the size of the sports field. The above shows different kinds of pressure indexes in a simple situation. If the game tool is transmitted to a new player, new measurements can be carried out, depending on which pressure index it is desired to have determined. The measurements can be carried out continuously for a selected period of time, and in that manner it is possible to obtain different total pressure in- dexes. A total pressure index can either be in the form of a sum or an average of continuous measurements of a pressure index. The continuous measurements could be used eg for studying a total pressure index in various phases as the game proceeds. Likewise, the continuous measurements could be used for studying a total pressure index for each time a player in possession of the game tool is present in a specific area of the sports field. A total pressure index for a specific opponent, a team or the game as a whole could also be studied over a selected period of time. The position determination is enabled by use of stationary cameras. The camera is calibrated relative to reference points on the sports field (eg all lines, corner flags and goals), whereby distances on the recorded pictures can be determined. The recorded pictures are analysed in relation to refer- ence pictures that are continuously updated to take into account changes in light due to changes in weather. By subtracting the pixel value of the actual picture from the pixel value for the reference picture, an absolute value is obtained. If the absolute value exceeds a given threshold, an object is detected on the actual picture. By means of probability calculations relative to the proportions of a human being or a game tool, it is deduced whether the detected object is a player or a game tool. By relating the player/the game tool to the reference points, an (x,y) position for player/game tool can be determined per analysed picture. The position determination is enabled by means of special cameras that are equipped with sensors on a camera stand and lens. Before the game starts camera stand as well as lens are calibrated by zooming maximally in on various reference points on the sports field (eg corner flags, goal and centre of the sports field). By means of very accurate laser binoculars the distances to the various reference points are determined. Sensors in the camera then inform a powerful computer how the camera moves and which distance setting is used. Then the coordinates for various positions on the sports field can be calculated. It is not possible to track different individuals on the sports field automatically. This is done after the live recording by means of a "slow- machine" where the objects are marked manually on the screen. If for instance the speed of running of a player is to be calculated, the position of a player is marked on the screen in the starting and end phases, and the distance between the two positions and the time spent make it possible to calculate the speed of running. This, however, constitutes prior art, as it is known from airport and coastline surveillance to use radar systems with associated displays to track targets indicated on a video screen. The prior art will therefore enable establishment of the tracking of players, opponents and game tool. A third option of automatically determining the position resides in equipping each player, each opponent and the game tool with a signal transmission unit. By locating a signal transmitter on a player, an opponent or the game tool, at least three signal receivers (Si, S 2 and S 3 ) in various positions along the sports field will be capable of determining the position of each player, opponent or the game tool on the basis of a phase difference between the signals received. Now positional data can be transmitted to a computer that will subsequently automatically and continuously determine the position of any object on the sports field that is equipped with a signal transmitter. On the basis of the data received the computer will be capable of calculating pressure index for one or more selected players, running speeds for players and opponents, and various statistical data on selected players, selected opponents, the game tool and selected places in the sports field. A fourth option of automatically determining the position resides in equipping each player, each opponent and the game tool with a signal transmitter that transmits a signal periodically. By locating at least three signal receivers (Si, S 2 and S 3 ) in different positions along the sports field it is possible to determine the position of a player, an opponent or the game tool on the basis of differences in time of receipt of the signal. The data received can now automatically be transmitted to a computer for further calculating pressure indexes for one or more selected players, running speeds for players and opponents, and various statistical data on selected players, selected opponents, the game tool and selected points in the sports field. Optionally the signal transmitter on a player, an opponent or the game tool be configured as a transponder that transmits position data only in case a query is submitted in the form of a coded signal from one or more transmitters along the sports field. A fifth option of automatically determining the position resides in equipping each player, each opponent and the game tool with a Global Positioning System (GPS) receiver and a signal transmitter. The number of signal receivers around the sports field can then optionally be reduced to one, the signal receiver being merely to function as a data link between the different signal transmitters and a computer. On the basis of the received data, the computer will be capable of calculating pressure index as described previously. Figure 4 expresses that the pressure from an opponent (M1 ) is calculated as an average over time (t), weighted by a constant (Vi), of the difference (an) between the distance between the actual positions (ar n ) of the player (Xi) and the opponent (M1 ) and the distance between the ideal positions (idai) of the player (Xi) and the opponent (M1 ) during the time (t m , t f ) when the player (Xi) is in possession of the game tool, and where the constant (Vi) is an ex- pression of the pressure significance of an opponent. Figure 5 expresses that the pressure from an opponent (M1 ) is calculated as an average over time (t), weighted by a constant (Vi), of the speed (V I of the opponent (M1 ) during the time (t m , t f ) when the player (Xi) is in posses- sion of the game tool and where the constant (Vi) is an expression of the pressure significance of an opponent. Figure 6 expresses that the pressure from an opponent (M1 ) is calculated as an average over time (t), weighted by a constant (Vi), of the difference (an) between, the distance between the actual positions (ar n) of the player (Xi) and the opponent (M1), and the distance between the ideal positions (idai) of the the player (Xi) and the opponent (Mi) during the time (tt, t m ) during which the game tool is transmitted in the direction of the player (Xi) plus the difference (a B n) between the distance between the actual positions (a B Mi) of the game tool and the opponent (M1) and the distance between the ideal positions (ida B ι) of the game tool and the opponent (M1 ) during the time (t m , t f ) when the player (Xi) is in possession of the game tool and where the constant (Vi) is an expression of the pressure significance of an opponent. Figure 7 shows that the pressure from an opponent (M1 ) is calculated as an average over time (t), weighted by a constant (Vi), of the speed (V I of the opponent (M1 ) in the direction of the player (Xi) during the time (t t , t m ) when the game tool is transmitted in the direction of the player (Xi) plus the speed (v B Mit) of the opponent (M1 ) in the direction of the game tool during the time (t m , tf) when the player (Xi) is in possession of the game tool, and where the constant (Vi) expresses the pressure significance of an opponent. Figure 8 shows that the pressure from an opponent (M1 ) is calculated as an average over time (t), weighted by a constant (Vi), of the reciprocal value of the difference (an) between the distance between the actual positions (ar n) of the player (Xi) and the opponent (M1) and the distance between the ideal positions (idai) of the player (Xi) and the opponent (M1 ) during the time (tt, t m ) when the game tool is transmitted in the direction of the player (Xi) plus the reciprocal value of the difference (a B n) between the distance between the actual positions (a BM i) of the game tool and the opponent (M1 ) and the distance between the ideal positions (ida B ι) of the game tool and the opponent (M1) during the time (t m ,t f ) when the player (Xi) is in possession of the game tool, and where the constant (Vi) is an expression of the pressure signifi- cance of an opponent. Figure 9 shows that the pressure from an opponent (M1) is calculated as an average over time (t), weighted by a constant (Vi), of the speed (V I of the opponent (M1 ) in the direction of the player (Xi) divided by the difference (an) between the distance between the actual positions (a M i) of the player (Xi) and the opponent (M1 ), and the distance between the ideal positions (idai) of the player (X ) and the opponent (Mi) during the time (tt, t m ) during which the game tool is transmitted in the direction of the player (Xi) plus the speed (V B Mit) of the opponent (M1) in the direction of the game tool divided by the difference (a B n) between the distance between the actual positions (a BM i) of the game tool and the opponent (M1 ) and the distance between the ideal positions (ida B ι) of the game tool and the opponent (M1 ) during the time (t m , t f ) when the player (Xi) is in possession of the game tool and where the constant (Vi) is an expression of the pressure significance of an opponent. Figure 10 shows that the pressure from the rearmost opponent (Mb) is calculated as an average over time (t), weighted by a constant (V b ), of the speed (VFMM) of the rearmost opponent (Mb) in the longitudinal direction of the sports field divided by the difference (a Bt ) between the distance between the actual positions (a BM b) of the game tool and the rearmost opponent (Mb), and the distance between the ideal positions (ida BMb ) of the game tool and the rearmost opponent (Mb) during the time (tt, t f ) that lapses from the game tool is transmitted in the direction of the player (Xi) until the player (Xi) is no longer in possession of the game tool and where the constant (VMB) is an expression of the pressure significance of a rearmost opponent. Figure 11 shows that the ideal distance (ida BMb ) for the rearmost opponent (Mb) relative to the location of the player (Xi) in the longitudinal direction is given by the difference between the actual length (L) of a sports field divided by two and a fraction having a numerator that is the actual length (L) of the sports field multiplied by the distance (a Bmέ ) between the goal line and player (Xi), and the fraction has a denominator that is the difference between the actual length (L) of the sports field multiplied by two and the determined smallest distance (a bmin) between the rear line and the rearmost opponent (Mb) multiplied by two. Figure 12 shows that the pressure from the rearmost opponent (Mb) is calculated as an average over time (t), weighted by a constant (V b ), of the speed (VFMM) of the rearmost opponent (Mb) in the longitudinal direction of the sports field divided by the difference (a M b t ) between the distance between the goal line and the actual position (a b m a ) of the rearmost opponent and the distance between the rearmost opponent (Mb) and the maximal pressure position (a M bmax) during the time (t t , t f ) that lapses when the game tool is transmitted in the direction of the player (Xi) until the player is no longer in possession of the game tool, and wherein the constant (V b) is an expression of the pressure significance of a rearmost opponent. Figure 13 shows a correction factor for the actual area of the sports field, where the correction factor constitutes the sum between 1 and a fraction with a nominator that is the maximal area of a sports field minus the product of the actual width (B) of a sports field and an actual length (L) of a sports field, and the fraction has a denominator that is the maximal area of the sports field, where the maximal area of the sports field is the maximal length of a sports field multiplied by the maximal width of a sports field. Figure 14 expresses a correction factor for the actual area of the sports field, 5 where the correction factor constitutes the difference between 1 and a fraction with a nominator that is a maximal sports field area minus the product of an actual width (B) of a sports field and an actual length (L) of a sports field, and the fraction has a denominator that is the maximal area of the sports field where the maximal area of the sports field is the maximal length of a sports l o field multiplied by the maximal width of the sports field. Figure 15 expresses a pressure index based on the distance alone as the pressure from an opponent, M1 , multiplied by an increment correction factor for the actual area of the sports field. 15 Figure 16 expresses a pressure index based on the speed alone as the sum of pressure from the two most proximate opponents (M1 and M2) multiplied by an increment correction factor for the actual area of the sports field. 20 Figure 17 expresses a pressure index as the sum of a standardized expression of the pressure based on the distance from the two most proximate opponents (M1 and M2) and a rearmost opponent (Mb), and wherein the sum of pressure is multiplied by a decrement correction factor for the actual area of the sports field. 25 Figure 18 expressses a pressure index as the sum of the pressure based on the speed and distance from the three most proximate opponents (M1 , M2, M3) and a rearmost opponent (Mb) multiplied by a decrement correction factor for the size of the sports field. 30 Figure 19 expresses a pressure index as the sum of the pressure from the three most proximate opponents (M1, M2 and M3) and the rearmost opponent (Mb) divided by 4 (the average) multiplied by a decrement correction factor for the size of the sports field. If it is chosen eg to set the ideal positions at zero in the given expressions of pressure index, the expressions figure 4, 6, 8, 9, 10, 15, 17, 18 and 19 could be reduced. These reduced expressions will be attractive, eg when the calcu- lation capacity is limited or where it is desired to merely have an estimate of the pressure index and in situations where there are several opponents included in the pressure index and it is simultaneously desired to avoid to have subjective weighting of the significance of the opponents to the pressure. Other expressions of pressure index may also occur. The expressions of pressure index, Figures 4 through 19, may be expanded to also include the direction (angle) from which at least one opponent (M1 ) is coming (is positioned in) relative to the player (Xi). This may also form the basis of a directional weighting. For instance, the weighting of an opponent coming from be- hind will typically have value that is different from the situation where the same opponent came from in front. The expressions of pressure index, Figures 4 through 19 may also be expanded to also include eg the direction (angle) at which at least one goal is situated relative to a player (Xi), and correspondingly relative to at least one opponent (M1 ). This may then form the basis of a further directional weighting relative to at least one goal. For instance, the weighting of a player (Xi) and correspondingly the weighting of an opponent (M1 ) that moves in the direction of the goal of the opponents will typically have a value that is differ- ent from the situation where the player (Xi), corresponding to the opponent (M1 ), was moving away from the goal of the opponent.

Claims: C l a i m s 1. A method of determining pressure index in a game, where said game takes place in a sports field, and where the sports field is provided with at least one goal, where the game comprises at least two teams and at least one game tool, and where each team consists of at least one player, where the method uses means of determining the positions of players and game tool, characterised in that the determination of positions is transmitted to a computer, following which the pressure index on any player (Xi) in control of the game tool is calculated by computer as the sum of pressure from at least one opponent (M1 ); and wherein is included at least one function of distance and time between at least one opponent (M1 ) and the player (Xi); wherein the time constitutes at least the time that lapses form the player (Xi) receives the game tool until the player (Xi) is not longer in possession of the game tool. 2. A method of determining pressure index in a game according to claim 1 , characterised in that the function of speed and time constitutes the speed of an opponent. 3. A method of determining pressure index in a game according to claim 1 , characterised in that a function of speed and time constitutes the acceleration of an opponent. 4. A method of determining pressure index in a game according to at least one of claims 1 through 3, characterised in a computer calculation wherein is included at least the distance between an opponent and the game tool. 5. A method of determining pressure index in a game according to at least one of claims 1 through 4, characterised in that the time that lapses from the game tool is transmitted in the direction of the player (Xi) until the player (X ) is in possession of the game tool is included in a computer calculation of a pressure index. 6. A method of determining pressure index in a game according to at least one of claims 1 , 4 and 5, characterised in that the pressure from an opponent is calculated by computer as an average of the difference between the actual distance of the opponent and the ideal distance of the opponent rela- tive to the player (Xi) during the time that lapses from the game tool is transmitted in the direction of the player (Xi) until the player comes into possession of the game tool, plus the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player (Xi) comes into possession of the game tool until the player is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. 7. A method of determining pressure index in a game according to at least one of claims 1 , 2, 4 and 5, characterised in that the pressure from an opponent is calculated by computer as an average of the speed of the opponent in the direction of the player (Xi) during the time that lapses from the game tool is transmitted in the direction of the player (Xi) until the player (Xi) comes into possession of the game tool, plus the speed of the opponent in the direction of the game tool during the time that lapses from the player (Xi) comes into possession of the game tool until the player is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. 8. A method of determining pressure index in a game according to at least one of claims 1 , 4 and 5, characterised in that the pressure from an opponent is calculated by computer as an average of the reciprocal value of the difference between the actual distance of the opponent and the ideal dis- tance of the opponent relative to the player (Xi) during the time that lapses from the game tool is transmitted in the direction of the player (Xi) until the player (Xi) comes into possession of the game tool, plus the reciprocal value of difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player (Xi) comes into possession of the game tool until the player (Xi) is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. 9. A method of determining pressure index in a game according to at least one of claims 1 , 2, 4 and 5, characterised in that the pressure from an opponent is calculated by computer as an average of the speed of the opponent in the direction of the player (Xi) divided by the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the player (Xi) during the time that lapses from the game tool is transmitted in the direction of the player (Xi) until the player (Xi) comes into possession of the game tool, plus the speed of the opponent in the direction of the game tool divided by the difference between the actual distance of the opponent and the ideal distance of the opponent relative to the game tool during the time that lapses from the player (Xi) comes into possession of the game tool until the player (Xi) is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of an opponent. 10. A method of determining the pressure index in a game according to at least one of claims 1 , 2, 4 and 5, characterised in that the pressure from a rearmost opponent (Mb), who is different from the goal keeper, is calculated by computer as an average of the speed of the rearmost opponent (Mb) di- vided by the difference between the component for the actual distance of the rearmost opponent to the game tool in the longitudinal direction of the sports field and the component for the ideal distance of the rearmost opponent relative to the game tool in the longitudinal direction of the sports field during the time that lapses from the game tool is transmitted to the player (X^ until the player (Xi) is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of the rearmost opponent (Mb). 11. A method of determining the pressure index in a game according to at least one of claims 1 , 2, 4 and 5, characterised in that the pressure from a rearmost opponent, who is different from the goal keeper, is calculated by computer as an average of the speed of the rearmost opponent (Mb) divided by the difference between the actual distance of the rearmost player (Mb) in the longitudinal direction of the sports field to the goal line and the maximal pressure distance of the rearmost opponent during the time that lapses from the game tool is transmitted to the player (Xi) until the player (Xi) is no longer in possession of the game tool; and wherein the average is weighted by a constant, where the constant is an expression of the pressure significance of the rearmost opponent (Mb). 12. A method of determining the pressure index in a game according to at least one of claims 1-11 , characterised in that the sum of pressure from at least one opponent (M1 ) and maximally an entire team of opponents (M1 , M2, M3 ... ) are corrected for the size of a sports field by means of a correction factor, where the correction factor constitutes the sum of one and a fraction having a numerator that is the maximal area of a sports field minus the product of the actual width (B) of a sports field and the actual length (L) of a sports field, and the fraction has a denominator that is the maximal area of the sports field, where the maximal area of the sports field is a maximal length of a sports field multiplied by a maximal width of a sports field. 13. A method of determining the pressure index in a game according to at least one of claims 1-11 , characterised in that the sum of pressure from at least one opponent (M1) and maximally an entire team of opponents (M1 , M2, M3 ... ) is corrected for the size of a sports field by means of a correction factor, where the correction factor constitutes the difference between 1 and a fraction having a numerator that is a maximal area of a sports field minus the product of an actual width (B) of a sports field and an actual length (L) of a sports field, and the fraction has a denominator that is the maximal area of the sports field, where the maximal area of the sports field is a maximal length of the sports field multiplied by a maximal width of a sports field. 14. A method of determining the pressure index in a game according to at least one of claims 1-13, characterised in that the pressure index on a player (Xi) in possession of the game tool is calculated by computer as the average of the pressure from at least one of the opponents (M1 ) and maxi- mally an entire team of opponents (M1 , M2, M3 ... ) multiplied by a correction factor for the size of the sports field. 15. A method of determining the pressure index in a game according to at least one of claims 1-14, characterised in that a total pressure index is cal- culated by computer by an average of continuous measurements of a pressure index on any player (Xi) in possession of the game tool. 16. A method of determining the pressure index in a game according to at least one of claims 1-15, characterised in that the collection of data for de- termining the position of the individual player and the position of the individual opponent and the position of game tools is determined by means of video monitoring equipment. 17. A method of determining the pressure index in a game according to at least one of claims 1-15, characterised in that the collection of data for determining the position of the individual player and the position of the individual opponent and the position of game tools is determined by means of transmitters mounted on the individual player and transmitters mounted on the individual opponent and transmitters mounted on the game tools and at least one signal receiver located along the sports field.

Inventors: MELVANG JENS, MELVANG, JENS
Applicants: JM KONSULENT FA, MELVANG JENS, JM KONSULENTFIRMA, MELVANG, JENS
Application year: 2001
Main classification: A63B71
IPC codes: A63B71, G01S5, G01S11, G06F17, G06T7