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
The technology is was then turned into a commercial
product by the spinoff company Hawk-eye Innovations Ltd.
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.
Intrinsic 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.
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
Knowing position of sun and position of the ball in previous
frame becomes useful for eliminating shadow of the ball during
Determines accurately the position of the ball in 3D.
2D position calculation
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
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