A group of three Masters students in the field of Mechatronics Engineering from National University of Sciences and technology (NUST) did a project under the title ‘Validation of the hawk-eye system in cricket’ as the semester project for the subject ‘Digital Image Processing’ and made an interesting discovery.
The students wrote a MATLAB code which would take three variables, location of the ball pitched, location of the impact and dimensions of the wickets and find out whether the hawk-eye trajectory mapped was correct or not. Also, if the trajectory was wrong, it would map the correct trajectory.
According to the students, the code can be divided into four parts. The first part is to load the image and convert it into grayscale. The second part is to obtain points using data cursor in MATLAB figure bars and then draw a spline from the location where the ball pitched to the point of impact. The third part is to draw a trajectory from point of impact to the wickets. This is done by creating a slope that will add in the point of impact with the length given to it. The fourth and last part is to give the decision. The boundary conditions of the wickets are given and the result can be found out.
The students took four sample cases for their project report. In three of the cases, the hawk-eye’s trajectory was proved to be correct. For example in the following figure, the original result was out, but hawk-eye showed it to be not out and the decision was overturned. The hawk-eye trajectory for this case was proved to be correct by the
Similarly in two other cases, trajectory was proved to be correct. But in one of the cases which was from the World Cup 2011 semi final between Pakistan and India at Mohali, results were shocking. On a ball of Saeed Ajmal, Sachin Tendulkar was adjudged LBW by the field umpire. Tendulkar went for referral and the decision was overturned. In the following figure, the hawk-eye projection with the help of which decision was overturned is shown. The figure shows that the trajectory has been tampered and the code also found out that the trajectory was tampered by an angle of 18.826 degrees.
The code then plotted the original trajectory for Saeed Ajmal’s delivery, the figure of which is shown below. It can be seen that that according to the original trajectory, the ball was hitting the stumps.
The students say that the system has been mailed to ICC to validate the hawk-eye system. They also said that they have asked them to have a look at this special case. They said that the code was under validation by their review team under the disciplinary committee members of ICC and that they were expecting a positive feedback from them.