An Augmented Reality in

Sports Broadcasting and Officiating

By PRAVEENA.C.S ROLL NO 45 S7 CSE

Hawk-Eye is a computer technology used in sports to visually track the path of the ball and display a record of its most statistically likely path as a moving image

INTRODUCTION

Basic idea is to monitor the trajectory of the ball during the entire duration of play. Data is then processed to produce visualizations showing the paths which the ball took. Such data has been used for various purposes, popular uses including the LBW decision making software and colorful wagon wheels showing various statistics.

A system comprising of video cameras mounted at specific angles can be used to take pictures. Pictures are then used to locate the position of the ball. The images are then put together and superimposed on a predetermined model to form a complete visualization of the trajectory of the ball by sampling images at a very high rate.

OVERVIEW

The Cameras

Preparation before starting to process

Core Image Processing Job

Putting frames at various times together

120 Mhz frame rate Fixed to some frame of reference

Modes

• Active Mode

• Passive Mode

A predetermined model is loaded.

The statistics generator might also aid in storing data such as the average velocity of the ball.

This data is crucial as it can help the ball detection algorithm to predict the rough location of the ball in an image given the position in the previous image

Identifying pixels representing the ball in each image.

Applying a geometric algorithm.

Plotting up the 3D position of the ball in space.

An algorithm is used to find the pixels corresponding to the ball in the image obtained.

A blob detection scheme can be used to detect the ball

At times a camera might return “NOT FOUND”

TRIANGULATION Process

Determines accurately the position of the ball in 3D.

Two sub-processes

2D position calculation

Depth calculation

Triangulation is the process of how a point could be located from the angles subtended from three known points, but measured at the new unknown point rather than the previously fixed points

l

d

Let us assume that the radial angle, as seen from the wickets marked in the figure, between Camera 1 and Camera 2 is θ and the radius of the field is r.

The two parts to this computation are:

(a) Tracking the ball at various instants.

(b) Predicting the flight or trajectory of the ball.

Putting Frames Together

Tracking the ball at Various Instants

The images are taken by cameras at times t0, t1,…..,tn during the play of a single ball. Computation done at each time instant, ti ,0≤i≤n we will get n points, say (xi,yi,zi) for 0≤i≤n.Plot the n points.

There is a standard technique, used commonly i.e.Computer Aided Geometric Design The more points we can get on the curve and the higher degree of polynomial basis we choose to use, we will end up with better approximations to the original curve. It goes through some points which are of special interest. These include the ball hitting the pitch, the stumps, and the batsman among others.

Predicting the Flight or Trajectory of the ball

Applications of Hawk Eye

Mainly used in ball games with predetermined area. Especially Cricket,Tennis and Snooker.

Strategy formulation and studies.

Gathering statistics

LBW Decisions

Wagon Wheels

The trajectories which the ball has taken after being hit by the batsman are recorded in the system. This is used to generate a graphic showing 1s, 2s, 3s, 4s, and 6s all in different colours for a batsman.

Pitch Maps

As shown above, the Pitch Map graphic uses information about the position where the ball bounced on the pitch. The image above clearly shows the pitch being divided into various “zones” which the experts consider in their analysis.

Despin:

RailCam: Beeehives:

Snooker

This technology is useful in cases where the path of the cue ball can be

tracked.

CONCLUSION

We have thus seen that the HAWKEYE is a great innovation, which puts technology to good use in the field of sports. New innovations within the system is being developed. The technology is used widely these days, in sports such as Tennis and Cricket. Very fast and accurate. Hawk Eye is currently developing a system for Football.