Determination of hitting the ball in tennis. Tennis. Rules of the game of tennis

The device is intended for use in the field of sports to serve competitions and improves the accuracy of determining where the ball falls on the court. Triboelectric sensors made in the form of a set of insulated wires are used as sensors. The wires are located under the surface of the site parallel to the marking lines. The sensor signal is generated by the electrical charge generated when the ball hits the surface of the court when the ball rubs against the surface of the court. All sensors are connected to a signal collection unit, which is connected to a signal processing unit that determines where the ball falls.

The invention relates to the field of sports, namely to technical means for servicing competitions. The invention can be used to determine where the ball fell on the court (the ball hit the playing field or went out of touch) in games such as tennis and volleyball, as well as for similar purposes in other sports. In most cases, the determination of where the ball fell, namely the determination of the fact whether the ball hit the playing field or went into touch, is made by the referee based on his own subjective visual sensation or on the basis of the subjective visual sensation of the line referees. According to the rules of tennis (and volleyball), the ball is considered to have entered the playing field if at least the edge of the ball touches the line limiting the playing field. A significant drawback of the work of a judge is his subjectivity. This is especially noticeable when playing matches on artificial turf courts, where the ball, when dropped, leaves virtually no imprint on the surface of the court and there is no way to check the correctness of the decision made by the referees. Often this significantly affects the entire course of the match, especially when the players have different attitudes towards the correctness of the decision made by the referee, and ultimately affects the determination of the winner of the match. A device is known for determining where the ball falls on the court when playing tennis, based on the use of sensors that respond to the shading of light beams located near the service lines by the ball. Signals from the sensors go through the signal collection unit to the signal processing unit - the computer. The computer analyzes the signals and determines whether the ball entered the playing field (serving square) or went out of touch. A similar device is currently used in competition practice to control service lines. The disadvantages of this device are that it cannot be used to control other lines of the court, since the ray shading signal can appear not only from the ball, but also from the tennis player’s feet. The signal acquisition unit and the signal processing unit are an essential, but not the determining part of this and other similar devices. The determining factor is physical mechanism signal acquisition and design of sensors. The signal acquisition unit is currently, as a rule, built on the basis of standard multi-channel analog-to-digital converters, and the signal processing (numerical processing) unit is based on a computer. In principle, other things are possible (including for the proposed device) technical solution a signal acquisition unit and a signal processing unit based on analog circuits traditional for electronics of the past. A known device is based on the use of sensors made in the form of a plurality of coils located under the surface of the site near the lines, in combination with the use of a special ball containing metal or ferromagnetic material. The sensors react to the ball's disturbance of the electromagnetic field of the coils. The use of the device in competition practice is unknown. Its main disadvantage is that to ensure performance, a special (non-standard) ball is required, which is difficult to manufacture in accordance with existing requirements (weight, rebound height, etc.). A known device is based on the use of a system of bare wires located on the surface of the court next to the lines, parallel to these lines outside them, in combination with a special ball having an electrically conductive shell. When the ball falls, two or more wires are connected to each other. Signals from all wires are collected by a signal collection unit connected to a signal processing unit - a computer that produces a signal in case of an "out" and does not output anything otherwise. The use of the device in competition practice is unknown. Its main disadvantages include the fact that it requires a special (non-standard) ball, which is difficult to manufacture in accordance with existing requirements, and a special (non-standard) court surface. The closest analogue of the claimed invention is a device for determining the location of the ball falling on the court, consisting of a set of sensors, a signal collection unit and a signal processing unit, with all sensors connected to a signal collection unit, which is connected to a signal processing unit that determines the location of the ball fall ( see US patent 5908361, class G 08 B 5/00, 1999). The technical result of the invention is to increase the accuracy of determining the location of the ball falling onto the court. This improves the objectivity of refereeing and the objectivity of determining the winner of the match. This technical result is achieved by the fact that in the known device for determining the location of the ball falling on the court, consisting of a set of sensors, a signal collection unit and a signal processing unit, all sensors are connected to a signal collection unit, which is connected to a signal processing unit, which determines where the ball falls, according to the invention, triboelectric sensors are used as sensors, made in the form of a set of insulated wires located under the surface of the court parallel to the marking lines, and the sensor signal is generated due to the electric charge generated when the ball hits the surface of the court when the ball rubs against surface of the site. Processing signals received from sensors located parallel to one of the lines makes it possible to determine the coordinate of the position of the edge of the ball closest to the line in the direction perpendicular to the line when the ball hit the surface of the court - this is exactly what is required to determine the fact: the ball hit the playing field or went out. The accuracy x of determining "out" is determined both by the distance between adjacent wires a and the distance between the wires and the surface h. As experience shows, with the chosen signal processing method x1/2(a 2 +h2) 1/2. Since each of the values ​​of a and h can be made quite small (less than) a few millimeters, this ensures high accuracy in determining the location of the ball falling on the court (no worse than 2-4 mm), and thereby ensures the determination of the winner of the match. In addition, the advantage of the device is that it ensures its performance when using all types of balls and all types of synthetic (artificial) coating and does not require any changes to their generally accepted properties. Using the device on natural surfaces (dirt and grass) is also possible in principle, although it is difficult to position the sensors close to the surface due to the low mechanical strength of the surface, and increasing the distance between the sensor and the surface leads to a decrease in measurement accuracy. INFORMATION CONFIRMING THE POSSIBILITY OF IMPLEMENTING THE INVENTION Structurally, the device for determining the location of the ball fall in the version of the device implemented by us consists of a set of triboelectric sensors, made in the form of insulated wires with a diameter of d = 0.8 mm (together with insulation), which were located directly on the surface of the concrete floor under a standard covering , used for tennis courts. Coatings from various companies with a thickness of 2-6 mm were used. In principle, when making special coatings, the wires can be placed inside the coating, at a smaller distance from the surface, which leads to increased accuracy in determining where the ball falls. Placing the wires at a distance from the surface of more than a few centimeters is hardly advisable due to the decrease in accuracy. The presence of wires of the specified thickness does not affect the rebound of the ball from the court. In principle, you can use wires of a different (including smaller) thickness, and also take additional measures to smooth the surface near the location of the wires, for example, place them in a recess in the floor (depth equal to d) or apply an additional layer of some kind between the wires. or material with a thickness equal to d. The wires were placed parallel to the marking lines with a step of 2 mm near the lines and 1 cm away from the lines. The total number of wires was 32 for one line. Some of the sensors (8 pcs.) were located on the inner side of the site relative to the line, the rest - on the outer side. In principle, the distance between the wires can vary from fractions of a millimeter to several centimeters, depending on the required accuracy in determining the location of the ball fall. In principle, sensors can be placed over the entire area of ​​the playing field and the entire area near it, but the number of processed signals will increase significantly and this is hardly advisable for ordinary courts. In addition, when the ball falls on the court away from the marking lines, the place where the ball fell is obvious to all participants in the match, including the referee and spectators. However, this may be useful when creating special training courts, when playing on which the player will know (for example, see on a special scoreboard) the exact coordinates of where the ball lands after any hit. Each sensor (wire) is connected to a signal collection unit made in the form of a device that measures voltage. Standard industrial multichannel analog-to-digital converters (ADCs) were used as a voltage measuring device, respectively 32 channels for one line. We selected twelve-bit ADCs with a built-in programmable amplifier with a maximum gain of K=1000. Thus, the system can record voltages from 0.5 μV to 2 V. The signal collection unit, in turn, is connected to a signal processing unit, made in the form of a computer, which processes the received data and, using the procedure described below, determines the location of the ball fall. The device operates as follows. When the ball falls onto the court near the lines on the sensors (wires) located near the place where the ball falls, an electric charge appears due to the triboelectric effect, which is recorded in the form of a voltage pulse U(t) by the signal acquisition unit (ADC). The voltage value is equal to U = R dQ/dt, (1) where R is the input resistance of the device measuring voltage (in our case, 10 6 Ohms), Q is the electric charge that appears on the sensor, dQ/dt is the rate of charge change over time. Since the ball is significantly deformed when falling, voltage pulses can occur simultaneously from several nearby sensors. Experiments have shown that the pulse duration is 1-3 ms depending on the type of coating used and, to a lesser extent, on the type of ball used. The pulse amplitude can change, but not more than 2-5 times, depending on each of the parameters: type of coverage, type of ball and its speed. In our case, the pulse amplitude varied in the range from 10 -3 to 10 -1 V. The computer constantly polls all ADC channels. The time interval between polls of each channel (in our case it is 50 μs) should be significantly less than the pulse duration. When the voltage on any channel exceeds the specified threshold amplitude U p (the criteria for choosing this value are described below), the recording mode is turned on and all signals from all channels are recorded for a time interval greater than the pulse duration (we used an interval of 10 ms). The ADC gain is selected and fixed for each coating so that the device responds to both the weakest and the strongest impacts. The dynamic range of the selected ADC (12 binary bits - 4 * 10 3) and the gain range (up to 1000) are sufficient to solve this problem. The received data from the signal collection block enters the signal processing block. The signal processing unit (computer) analyzes the recorded data (voltage pulses) received from various sensors. Data received from each group of sensors (32 sensors) located parallel to one of the lines is processed separately. Data processing is carried out as follows. First of all, the maximum amplitude of the received pulses M is determined. If the amplitude of the pulse from a certain sensor A>0.3 M, then it is considered that there is a signal from the sensor, and if A<0.3 М, то считается, что сигнала с датчика нет. Наличие сигналов (А>0.3 M) from sensors located with outside lines, and lack of signals (A<0.3 М) с датчиков, расположенных с внутренней стороны линий, свидетельствует о том, что мяч не попал в игровое поле (вышел в аут). На выходе блока обработки сигналов формируется звуковой и/или световой сигнал или сигнал иного вида, свидетельствующий о том, что мяч вышел в аут. При этом игра останавливается и работа устройства также останавливается. Поскольку сигналы записаны в компьютере, после остановки игры положение визуального образа области контакта мяча с поверхностью по отношению к линии может быть продемонстрировано судье, игрокам, зрителям на стадионе и телевизионной аудитории, таким образом обеспечивается возможность проверки результатов в случае сомнений. В случае, если мяч попал в игровое поле, никакого сигнала на выходе блока обработки сигналов не формируется и работа устройства продолжается в прежнем режиме. Возможно использование других критериев наличия и отсутствия сигнала и других алгоритмов обработки сигналов. Эксперименты показали, что выбор критерия в виде, указанном выше, обеспечивает точность определения положения ближайшего к линии края мяча на уровне 2-4 мм, что достаточно для практических применений. Аналогично строится обработка сигналов с линий, ограничивающих квадрат подачи (в случае игры в теннис, для волейбола этого нет). Датчики, контролирующие заданный квадрат подачи, включаются вручную (например, судьей) перед выполнением подачи и отключаются вручную или автоматически (например, по звуку удара мяча о корт) после выполнения подачи. Формально сигнал трибоэлектрических датчиков может возникать не только при ударе мяча, но и при движении ног игрока вблизи линии, что могло бы приводить к появлению ложных сигналов. Однако на практике эта проблема оказалась не столь существенной, так как амплитуда импульсов от игрока оказалась значительно (более чем на порядок) ниже чем от самого слабого удара мяча. Физическая причина этого состоит в том, что характерное время контакта ноги с кортом (составляющее даже при беге около 100 мс) по крайней мере в 30-100 раз больше чем время удара мяча о корт, соответственно скорость образования зарядов при трении оказывается более чем на порядок ниже, что и приводит в соответствии с выражением (1) к указанному выше различию в амплитудах сигналов. Проблема отделения ложных сигналов решается просто соответствующим выбором величины пороговой амплитуды U п, которая настраивается индивидуально для каждого типа покрытия таким образом, чтобы устройство реагировало на самый слабый удар мяча и не реагировало на игрока. Аналогично могут быть решены проблема определения места падения мяча при игре в волейбол и проблемы в других аналогичных играх, в которых попадание мяча или другого предмета в площадку, ограниченную линией, является критерием успеха. Возможно также использование устройства для определения координат места падения какого-либо предмета. Так, например с помощью этого устройства может быть решена проблема определения положения ноги спортсмена в момент отталкивания в соревнованиях по прыжкам в длину (есть заступ или нет). Возможно также использование этого устройства для определения дальности полета снаряда в соревнованиях по метанию молота, диска, копья и толканию ядра. Таким образом, предлагается устройство для определения места падения мяча на площадку. При этом достигается автоматическое и объективное определение с высокой точностью места падения мяча на площадку, допускающее проверку результатов в случае сомнений. Это повышает объективность судейства и объективность определения победителя матча. Устройство обеспечивает свою работоспособность при использовании всех видов мячей и всех видов покрытия и не требует каких-либо изменений их общепринятых свойств. Кроме того, существенно снижаются расходы на проведение соревнований, так как при использовании изобретения отпадает необходимость привлечения линейных арбитров. ИСТОЧНИКИ ИНФОРМАЦИИ 1. Патент США, US Patent 4,867,449, "Electrically operated line monitor for tennis", Carlton et al. 19.09.89. 2. Патент США, US Patent 4,664,376, "Line fault detector". Gray, 12.05.1987. 3. Патент США, US Patent 4,071,242, "Electrically conductive tennis ball", Supran, 31.01.1978.

Claim

A device for determining the location of the ball falling on the court, consisting of a set of sensors, a signal collection unit and a signal processing unit, with all sensors connected to a signal collection unit, which is connected to a signal processing unit, which determines the location of the ball fall, characterized in that Triboelectric sensors are used as sensors, made in the form of a set of insulated wires located under the surface of the court parallel to the marking lines, and the sensor signal is generated due to the electric charge generated when the ball hits the surface of the court when the ball rubs against the surface of the court.

The International Football Association Board (IFAB), which is responsible for the rules of the game, has decided to introduce an automatic goal detection system (goal-line technology - GLT). Two goal detection systems have received approval and will be tested.

The next round of controversy around the fact that a goal should be determined using high technology arose after the group stage match of the 2012 European Championship between Ukraine and England. In the second half, the ball was hit by Ukrainian forward Mark Devich crossed the English goal line, but neither the main referee, nor the additional referee, nor the sideline saw the goal. After the game, the Hungarian referee Viktor Kassai, who refereed that match, admitted his mistake, but this hardly made it any easier for all fans of the Ukrainian team.

The first talk that FIFA should keep up with the times began during the 2010 World Cup in South Africa. In the 1/8 final match between the teams of England and Germany, the ball after a long-range strike by English midfielder Frank Lampard ricocheted off the crossbar crossed the goal line and ran back into the field. However, the referee did not count the goal, and the match ended in victory for the German players (4:1).

The referee's mistake was seen by the whole world, and FIFA head Sepp Blatter also admitted it, who then had to justify himself and explain why his organization opposes the arrival of high technology. Examples were given of tennis, handball, cricket or rugby, where the latest scientific achievements help to understand controversial issues. Then the FIFA president stated that all this would lead to long stoppages and ultimately have a negative impact on the entertainment of the matches.

UEFA head Michel Platini also spoke out against it, according to whom refereeing errors are an integral part of football and cannot be avoided. In addition, new technologies, the head of UEFA noted, will certainly kill the “humanity” of football, which attracts fans to it. However, Platini decided to introduce additional referees who are located near the goal. But even this did not save. The example of Devich's disallowed goal against England is indicative. The ball crossed the goal line right in front of the additional referee, but he did not record a goal.

However, FIFA still had to listen to the critics and begin preparations for the gradual introduction of GLT. The criteria that these same systems must meet were determined. Firstly, the system must be 100% accurate, and secondly, it must notify the referee that a goal has been scored within a second (according to FIFA, long stoppages will ruin the game). Thirdly, the head detection system must work in all weather conditions and in any lighting (daylight or artificial).

Back in August 2011, testing of a dozen similar devices began, which ultimately resulted in the historic decision of IFAB. FIFA officials chose two systems: the British Hawk-Eye and the Danish-German GoalRef.

The Hawk-Eye system (which can be translated as “hawk eye”) is familiar to all tennis or cricket fans. Of course, football has its own specifics, but it is expected that six cameras will be installed at different points of the goal. The image they capture is automatically stitched together to determine the exact location of the ball impact. The referee then receives a signal whether a goal has been scored.

The GoalRef system is not as well known in the world of sports technology, but since 2009 it has been used to determine goals in handball. A magnetic field is created in the goal area, and a special sensor is installed inside the ball. If the ball completely crosses the goal line, the referee will know about this using a special signal and will be able to record a goal.

Each of the two systems has its pros and cons. It is unknown how the “hawk’s eye” will behave when there is a large concentration of players in the penalty area, whether all six cameras will be able to see the ball. However, Hawk-Eye should appeal to all fans, as it is expected that footage of goals scored or missed will be shown in the stadium itself and on television broadcasts.

The advantage of GoalRef is its simplicity and low cost. Almost no additional equipment is needed, the system will work in any conditions, even if all the players of two teams run into the goal along with the referees.

At the same time, FIFA may not abandon one of the systems. It is likely that both will be implemented at once. If a club has available funds, it can spend it on installing a “hawk eye” at its stadium. Poorer clubs will opt for GoalRef.

It is expected that the first major tournament at which one of these systems will be tested will be the club championship, which will be held in December 2012 in Japan. Then the innovations will be used at the 2013 Confederations Cup and at the 2014 World Cup, which will be held in Brazil. In the future, it is planned to introduce it at the level of national championships.

New technologies could be adopted earlier than the deadlines set by FIFA. The management of the English Premier League intended to use the "hawk's eye" from the 2012/13 season. However, not all stadiums were equipped with the necessary equipment. And now in England Hawk-Eye will begin to be used from the middle of the next championship or starting from the 2013/14 season. But it is already possible to accurately determine whether there was a goal or not today at the main British stadium - Wembley, where the installation of cameras on the goal was recently completed. Also, new technologies should be introduced in the North American Major League Soccer (MLS) in the very near future.

It is obvious that nothing like this will appear in the near future in the most prestigious club tournament in Europe - the Champions League. The head of UEFA is pessimistic about the football of the future, in which a person will be replaced by a soulless machine.

But at the same time, FIFA supported the practice of introducing additional referees, which were used at the games of the Champions League, Europa League and European Championship 2012, as well as at various competitions in Brazil, France, Qatar and Morocco.

Also at the IFAB meeting, it was decided to allow the wearing of headscarves, or hijabs, in women's football. By the next meeting of the council, which will be held in October 2012, two types of scarves must be selected, which will then be used during the games. The ban on headscarves was introduced in 2007 in accordance with a football rule that prohibits the use of potentially dangerous equipment and equipment with religious content. The IFAB decision states that there is still no medical evidence that anyone has suffered from the hijab.

Due to the ban on hijab, many teams from Muslim countries refused to take the field. The most famous case was the story of the Iranian national team. In 2011, Iranian football players refused to go to the Olympic qualifying match against Jordan with their heads uncovered, for which they were disqualified. Even the United Nations has expressed its concern about the fact that female football players are not allowed to play in headscarves.

There is no doubt that the introduction of new technologies will benefit football. First of all, the number of refereeing scandals that damage the reputation of FIFA will be reduced. Now it will hardly be possible to call officials from world football “retrogrades”.

But the most important thing is that the goal of the game is still a goal against the opponent. Currently, teams devote so much effort to defending their own goal that the fate of an important match can sometimes be decided by just one episode. Even a small stop in the game is certainly better than a situation where all the efforts of the attacking team are nullified by an incorrect refereeing decision.

The International Tennis Federation remains the main architect and custodian of the Rules of the Game of Tennis. The original idea was to retain the hourglass shape of the court, conceived by Major Walter Clopton Wingfield, considered one of the founders of the game along with jury-tested Major Harry Jam. The length of the court was 23.5 m, the width at the baseline was 9 m, the width in the middle was 7.2 m. The height of the net at the edges was 1.5 m, in the middle 1.2 m, the service squares extended to 7.8 m from the grid. As in several racquet games, points (up to 15 to win a game) were awarded only to the server.

By the time of the first Wimbledon, the All England Club committee had made major changes: the introduction of a rectangular court shape 23.77 m x 8.23 ​​m), a scoring system - as is customary now. In addition, the height of the net in the middle was reduced to 97.5 cm. Eventually, by 1892, the height of the net was gradually reduced to 107 cm, and in the middle - 91.4 cm. In 1880, the feed line was installed at a distance of 6.3 m from midline, in the same year replay of serve was introduced. Previously, a ball that touched the net but was otherwise served correctly remained in play.

Permanent court accessories

Most of the permanent fixtures of the court are quite obvious - nets, posts, etc., as specified in the rules of tennis. However, not everyone knows that their list goes beyond these obvious items. For example, permanent or mobile seats and those who occupy them: chair umpire, net umpire, line judges are considered permanent fixtures of the court. And also the boys and girls serving the balls, in their respective places. Therefore, if during the game the ball hits any of them, the point continues. Likewise, if a player collides with the umpire at the net, it is his or her fault if he or she fails to hit the racket. At Wimbledon in 1993, there was a spectacular incident when Chris Bailey, on match point in the second round with Goran Ivanisevic, lunged forward to hit a short ball with an oblique and, instead of jumping over the chair umpire, crashed into her.

Many people know about the "hawk's eye", an electronic system for determining when the ball hits the court. The system was first used in 2006 at the NASDAQ-100 tournament.

The ball must have a uniform, smooth outer surface, the fabric cover of which must be white or yellow. If there are any seams on it and they should be smooth. Yellow balls were first used in the mid-1970s by the World Tennis Championships, a Dallas-based organization that predates the Open Era. The idea of ​​using yellow balls instead of the traditional white ones, which were used at Wimbledon until 1986, was born as a result of the advent of color televisions, on which the color is more visible on the screen.

Racket

Incredibly, until 1976 there were no rules governing the size, weight, shape or material from which a tennis racket was made. It was just a projectile for hitting the ball. You could even use a manhole cover.

Serving and receiving th

Many people wonder when watching a doubles match: is the receiver allowed to stand anywhere on his side of the court while waiting to serve? Answer: Yes. Likewise, in doubles play, the server and his partner may, if they wish, stand on the same side of the court in their own half; it is called the "Australian Position" because Australian players were the first to use it, even though it sometimes results in the ball hitting the back of the server's partner's head. Ask Mark Woodford or Todd Woodbridge!

Selecting sides of the court and service

The choice of sides of the court and the right to be the server and receiver in the first game is determined by lot (in our time it is a coin, but in those days when only wooden rackets were used, one of the players rotated the racket, and the other guessed which side was up, smooth or rough, she will fall). The player who wins the toss may choose, or force the opponent to choose, to serve or receive a serve. If one player chooses to serve, the other must choose the side of the court to play on at the start of the match.

Step by step

This rule has changed many times over the years, but remains controversial. Originally, in addition to the clause stating that the server may not change his starting position, it was stated that the server must "maintain contact with the ground" and also place his feet behind the baseline. The rule now reads as follows: “While serving, the server may not change his starting position by walking or running, although minor movements of the legs are permitted. The server may not touch the baseline or court surface with either foot. The server may not touch either foot surface of the site located behind the imaginary continuation of the middle mark." Since this time, there has been an increasing number of players who literally jump 5-10cm off the ground when serving, often leaning forward so that they are halfway to the net. Zwashag is the most common violation in tennis.

Error during submission

Many times a service error is obvious - when the ball misses the net, lands outside the opponent's service line, or misses the ball when serving. But what some beginning players don't consider is that while the ball remains in play if it touches various court fixtures, such as net posts, during a point, if the ball touches them before it lands, this is called an error. The exception is if the ball touches them when serving, but falls into the receiver’s serving square. In this case, the serve is replayed. By the way, serving from below is considered absolutely legal.

Tennis (tennis)- a sport in which two players or two teams of two compete with each other. The goal of each player/team is to throw the ball to the opponent's side with the racket so that the opponent cannot reflect it. In this case, the ball must touch the opponent’s half of the field at least once.

History of the emergence and development of tennis

The predecessor of tennis is considered to be the French game “jeu de paume” (French jeu de paume, literally playing with the palm). Unlike modern tennis, jeu de paume was played indoors and with the palm of the hand. Later, the palms were replaced by gloves, the gloves were replaced by special bats, and only then rackets appeared.

One of the most famous references to tennis in medieval literature is an episode in Shakespeare's historical chronicle Henry V, where the French Dauphin sends the young English king a keg of tennis balls as a mockery.

Almost all French kings played tennis; Charles IX called tennis “one of the most noble, worthy and healthy exercises that princes, peers and other noble persons can engage in.”

In 1900, students at Harvard University decided to organize a tournament for national teams. One of the students, Dwayne Davis, used his own money to buy a silver cup for the winner, and most importantly, he drew up the rules of the tournament. Davis and two of his friends played for the US team, which won this tournament and the next one in 1902. The Cup was held every year and was subsequently called the "Davis Cup", which is still a popular event in the world of tennis.

Beginning in the 1920s, professional tennis players began making money by playing exhibition matches. The first professional tennis match in history took place on October 9, 1926 in New York at the Madison Square Garden indoor arena, in the presence of 13 thousand spectators.

Rules of the game of tennis

Players or teams must be on opposite sides of the net. One of the players is the server, the second, respectively, the receiver. The serving player must send the ball so that it lands in the opponent's half of the court. The receiving player must have time to redirect (hit) the ball to the opponent's side before it hits the court or before it touches the court a second time. If one of the tennis players misses the ball, then his opponent gets a point.

A tennis match consists of “sets”, and they, in turn, are made up of “games”, to win which you need to score goals (minimum 4 goals: 15-30-40 game, but with a difference of at least two goals). When serving, the player has two attempts in which he alternates serving the ball to the left and right squares. After the game is played, the serve passes to the opponent. After playing an odd number of games, players are given a minute break and sides are changed. The first player to win 6 games (provided that his opponent has won no more than 4 games) is considered to have won the set. To win the match you need to win 2 out of 3 or 3 out of 5 sets. The player who reaches the required number of sets won wins the match.

The rules of doubles tennis are slightly different from singles, namely:

• the match takes place on a larger court;
• the ball is hit by the one who is in the best position;
• players of each team serve in turn;
• players only accept serves from their side throughout the entire set.

At official matches there is a referee, he is on the tower. In addition to the judge on the tower during the match, there may be line judges who record the ball entering the court area. Since 2006, tennis has seen the era of electronic refereeing systems (Eye of the Hawk), which accurately determine where the ball lands.

Tennis court

The standard size of a tennis court is 23.77 meters long and 8.23 ​​meters wide (10.97 meters for doubles). The area of ​​the tennis court is about 196 m2. To install tennis courts intended for competitions, an area of ​​668 m2 is required. The court has a rectangular shape with a flat surface with markings applied to it:

• The lines along the short sides of the court are called back lines, and along the long sides are called lineouts.
• The court is marked with service zones using service lines parallel to the back lines and the net, 6.40 m from the net and drawn only between the side lines for singles, and a center service line drawn in the middle of the court parallel to the side lines and between the service lines . The center service line is also indicated on the net by a vertical white stripe stretched from the surface of the court to the top edge of the net.
• A short mark is applied to the back lines to mark their middle.

There is a net stretched in the middle of the court, which runs across the entire width and divides it into two equal parts. The standard size of a tennis net is 1.07 meters by 12.8 meters, and has square cells with a side of 4 centimeters.

Types of tennis court surfaces:

• herbal (grass),
• ground (clay),
• hard
• synthetic carpets (artificial grass, acrylic coverings).

There are other types of tennis court surfaces, such as asphalt, wood or rubber, but these are not used in official matches. Tennis courts are available outdoor and indoor.

Tennis equipment

Tennis player equipment: tennis racket and ball. The racket consists of a handle and a round rim with stretched strings. The rim of the racket is made of complex composite materials (ceramics, carbon fiber, metal). Tennis racket strings can be either natural or synthetic. Previously, it was believed that natural strings had better characteristics, but today artificial strings have caught up with natural strings in terms of characteristics. Interestingly, the tension force of horizontal and vertical strings is usually different. Typically, a tennis racket is selected individually for each player.

There are special requirements for rackets from the International Tennis Federation (ITF):

• The length of the racket must not exceed 73.66 cm.
• The width of the racket should not exceed 31.75 cm.
• The size of the string surface of the racket, that is, the internal size (to the rim) is 29.21 cm in width and 39.37 cm in length.

The game is played using a yellow-white hollow rubber ball. The outside of the ball is covered with fluffy felt to impart certain aerodynamic properties.

Today, the English Premier League will officially opt for a goal determination system and become the first national championship to introduce high-tech technology to assist referees. You will have to choose from four technologies licensed by FIFA. We talk about the advantages and disadvantages of each of the four systems.

GOALCONTROL

Manufacturer: Germany

The essence: 14 high quality cameras are installed under the roof along the entire perimeter of the stadium. 7 cameras each The image is projected onto a 3D image. When the ball crosses the goal line, the referees receive a vibrating signal and the word “Goal” on a special clock within one second.

Advantages: The ability to display a virtual 3D trajectory of the ball on stadium scoreboards and television. High quality cameras. Already selected by FIFA as the core technology for the 2013 Confederations Cup in Brazil.

Flaws: Expensive technology. Not suitable for some older stadiums. It is not clear how the system will behave if the view of the ball is blocked by the bodies of the players.

What it looks like:

HAWK-EYE ("Hawk Eye")

Manufacturer: Great Britain

The essence: Works pretty much the same as GoalControl. Behind the goal and opposite the side lines of the penalty area there are 6 high-resolution cameras recording what is happening on the field with a frequency of 500 frames per second. With a delay of 0.5 seconds, a 3D image is transmitted to the central computer, in which the flight of the ball is tracked and the point of its contact with the surface is recorded. It instantly becomes clear whether the ball has crossed the line or not. The signal is then sent to the referee's wrist sensor or earpiece. The system works flawlessly provided that the cameras see at least 25 percent of the ball.

Advantages: Widely known brand, technology applied in tennis. The system was developed back in 2001 and since then has been repeatedly tested and improved. According to the British press, he will be the favorite in the vote.

Flaws: Expensive technology. Not suitable for older stadiums. The system may not work if the ball is blocked from the cameras by the players' bodies.

What it looks like:

GOALREF ("Goal Referee")

Manufacturer: Germany

The essence: Special sensors are installed on the posts and crossbar that create a magnetic field on the goal line. When the ball, which contains 3 small sensors, crosses the goal line, a goal signal is sent to the referee's wristwatch.

Advantages: Cheap technology. Suitable for any stadium. The effectiveness of the system does not depend on whether players block the ball from view.

Flaws: Requires special balls with sensors. There were complaints from players at the Club World Cup, where the system was tested, that the balls were unusual for them. The absence of a visual component that would give viewers the opportunity to understand the controversial episode.