Hawkeye Technology

ByVenkataraj RUSN:4su09ec065

Introduction

Hawk-Eye is a computer technology used in sports to visually track

the path of the ball developed in 2001.

It was developed by Dr. Paul Hawkins while working for Roke

Manor Research Limited.

Derived its concept from that of missile-tracking technology.

The technology is was then turned into a commercial product by the

spinoff company Hawk-eye Innovations Ltd.

Step by step analysis of Hawkeye system

The Cameras

JAI monochrome digital video cameras.Matrox Meteor-II multi-channel frame grabber supported by

Matrox Imaging Library (MIL-Lite) software.Operated in Active mode & Passive mode.

Calibration processIntrinsic Parameters: Parameters of the camera such as Focal

length, pixel skew and the principal point.Extrinsic Parameters: The location and orientation of the

camera in world space.Lens Distortion Coefficients: Radial and tangential coefficients

introduced as an artefact of the camera’s lens.Comparison between original and rectified image:

Core image processing job

Identifying pixels representing the ball in each image.

Applying a geometric algorithm (Triangulation).

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

Ball recognition

A blob detection scheme is used to detect the ball.

Blob represents group of pixels corresponding to the ball.

Knowing Size and Shape of object(i.e. ball) makes the detection easier.

Knowing position of sun and position of the ball in previous frame becomes useful for eliminating shadow of the ball during detection.

Geometric Algorithm

Triangulation Process:

Determines accurately the position of the ball in 3D.

Two sub-processes:

2D position calculation

Depth calculation

Triangulation

Determining the 3D position of the ball

The cameras are mounted at ground level, positioned with their vision parallel to the ground.

Triangulation is the process of determining three-dimensional world coordinates for an object given two-dimensional views of it from multiple cameras.

Three dimensional triangulation of camera rays:

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.

Predicting the Flight or Trajectory of the ball

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.

ApplicationsLBW 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.

Rail Cam:

Pitch Maps:

Beehives:

Prediction of the “in” & “out”:

Snooker:

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

CONCLUSION:Statistics Show..

Tennis Cricket

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