What is the meaning of the unforced error of ACE ball passing through the ball in tennis, and what is the eagle eye system?

Hawkeye system is a computer system used in cricket, tennis and other sports, which is used to track and record the path of the ball and display the graphic image of the recorded actual path, and also to predict the future path of the ball. In some sports, such as tennis, the Hawkeye system has become a part of the referee procedure. The Hawkeye system was developed on 200 1 by engineers from Roke Manor Research Limited in Ramsey, Hampshire, England. The patent is held by Paul Hawkins and Dr. David Shelley. Later, the technology broke away from the original company and set up an independent company: Hawkeye System Innovation Co., Ltd., a joint venture with TV production company Sunset+Vine.

The official name of "Hawkeye" is "instant playback system". The technical principle is not complicated, but it is very accurate. This system consists of eight or 10 high-speed cameras, four computers and a big screen. Firstly, with the help of computer calculation, the three-dimensional space in the competition venue is divided into measurement units calculated in millimeters; Then the basic data of tennis flight trajectory are captured from different angles by high-speed camera at the same time; Then through computer calculation, these data are generated into three-dimensional images; Finally, using real-time imaging technology, the movement route and landing point of tennis can be clearly displayed on the big screen. From data collection to result presentation, the time spent in this process does not exceed 10 second. Usually used for TV broadcasting.

As early as the beginning of 200 1, this technology won the scientific and technological innovation award of the Royal Television Association, and in 2003, it won the Emmy Award, the highest award in American television for its wide application in tennis broadcasting. For professional tennis players, it is a significant innovation to introduce eagle-eye technology into tennis spot penalty, which is comparable to the introduction of tiebreak system 36 years ago. American star Corell, a four-time Grand Slam winner who specializes in auditing the use of this technology, said: "This is a huge progress for a sport that rarely changes its tradition."

Each player can make two requests in each game.

Whether "Hawkeye" is correct or not, it must be the basis of the final judgment!

To some extent, it must be correct!

Eagle Eye Technology:

Eight high-resolution fast black-and-white cameras were placed around the stadium.

Position of the ball: Use software to calibrate the sideline of the court, so that the trajectory of the tennis ball can be displayed on the screen after being captured by various cameras.

3D technology is used to simulate tennis, and the imaging is based on the materials captured by three cameras designed in the "corner position".

Influence generation process: images are obtained from each camera at the speed of 2000 frames per second and transmitted to the main control computer.

After each frame is calibrated, the running route of tennis ball is determined, and the landing bounce point of the ball running along this trajectory is calculated to ensure that the error is controlled within 3 mm

In fact, Hawkeye technology has been frequently used in TV broadcasting. However, due to the high use cost of Hawkeye technology, the current competition is still dominated by wire cutting, and Hawkeye technology will only be applied to key points. Because of this, players have the right to apply for the use of Hawkeye twice in each set. If it is a draw, you can add it again. After accepting the application, the referee will play "instant playback" on the big screen to present the Hawkeye calculation results.

Involuntary error: unforced error, also known as active error, refers to the player's own active error in tennis, which leads to the ball returning to the net or out of bounds, regardless of the opponent.

The unforced errors in tennis match are directly related to the scoring trend, so the fewer unforced errors, the better the competitive state.

Outside tennis, we use this word to describe the mistakes we shouldn't make.

The significance of Hawkeye in tennis is to overcome the limitations and blind spots of human observation ability and help referees make accurate and fair judgments.

Crossing the ball: refers to one side's volley on the net, and the other side hits a quick return ball and scores in the line, but the online side fails to touch the ball.