Friday, October 30, 2009

Replay Technology Will NOT make 100% Correct Calls

More blown calls in a major sporting event. This time in the 2nd game of the Major League Baseball World Series, between the New York Yankees and the Philadelphia Phillies. Chase Utley of the Phillies was called out at first base, when video evidence suggested he had touched the base before the ball hit Mark Teixeira’s glove. In the same game Ryan Howard was judged to have caught out Johnny Damon, when the ball looked to bounce before hitting his glove. There have been a number of poor calls in this seasons MLB playoffs once again, and blown calls are happening in numerous other sports, including soccer and tennis.

The technology of high definition and high speed video of today can easily eliminate many of these blown calls. Sure there is the argument that using video replay can slow down the game. In baseball in particular this would be truly frustrating, but we would I think all prefer to see the right call made most of the time, particularly in big games such as the World Series.

Cricket is a great example of where camera technology is used to good effect. The cameras are setup side on to the crease (batters line) and can see both the wickets and the crease. In most cases just this one camera would be enough to determine the position of the batter as well as whether the wickets bails had been dislodged. If the umpire on the field is unsure of a run out situation, he will refer the decision to the camera technology, or the 3rd umpire, who will make a definitive decision after reviewing the video footage.

Although we definitely support the use of video analysis to assist umpires and referees, it is important that everyone; umpires, athletes and fans understand that even with video analysis a call can not be 100% correct every time.
Video footage cannot always capture the event from the correct angle or the video cannot be slowed down sufficiently to determine some calls. The fact is that the video footage may not show enough evidence to support or over rule a call.

Fans in particular make the mistake of believing that video evidence will always be able to determine whether a call is correct. Unfortunately this is not the case.
If the camera reviewing a line call or judgement does not have a direct view, then the video image may not help to determine the accuracy of the umpire's call. When close calls are viewed from an angle given by a television camera, they can sometimes give misleading evidence of the accuracy of the call. This can be particularly problematic for example, when using one camera angle to determine whether a base runner has been thrown out. The base runner is running between the bases and the camera could be setup at a good angle to view when the runner touches the base. However, and here is the problem, the ball may be thrown in to the fielder from anywhere on the field (this cannot be determined in advance), therefore the camera setup to view the runner may not be in the best position to accurately determine when the fielder caught the ball and it will be possible for incorrect judgements to be made. If on the other hand we have a great view of the fielders glove and ball, we may have the incorrect perspective of the base runner and when he touches the base.

Of course these 2 situations did not take place in the 2nd game of the MLB World Series, but they also cannot be discounted.

Take a look at the 2 photographs below.

In the above pic we have the view from one camera and shoe looks like it is on the edge of the mat.
Now lets take a look from a second camera with a better view of the edge of the mat and the shoe.

Of course it is pretty obvious from this camera angle that the shoe is just short of touching the mat.
From this we can see that the incorrect camera angle could result in an incorrect call.

The problem of incorrect camera angle could be solved by having multiple cameras, all synchronized with a time source and calibrated so that the 3D position of the ball can be determined. This is how the Hawk-Eye system for Cricket and the Tennis challenge system works. Beside the fact that this type of technology requires numerous cameras, can be very expensive and requires processing time before a decision can be made, it too can suffer from inaccuracies when the ball or target being tracked is hidden from the view of a number of cameras. This can often be the case when their are numerous players on the field, or the lighting is not ideal.

So we know that video analysis of umpiring and refereeing decisions are not 100% accurate. In fact the Hawk-Eye system claims they have an accuracy of 3.6mm. This means that the ball can miss the line by 3.6mm in Tennis and still be called in by the system. In NFL football when a call is challenged and a review takes place, often the result suggests that there is insufficient evidence and the call on the field cannot be over ruled. This insufficient evidence occurs because the camera cannot get the best view of the ball and its position because of the scrum of players or a camera angle that is not optimal.

The umpire or referee has a distinct disadvantage to technology. He or she only gets one chance to get it right. If they fail to get into the best position, have the best view of the play, find the best perspective to catch all the action and happen to blink at the critical point, they could easily make the wrong call.
The camera even with the possible errors in perspective or lighting and the small errors with 3D tracking , can capture high resolution and high speed footage and replay it over and over again.
This advantage will ensure that technology will get the call right more often than even the best and luckiest umpires and referees and should be used whenever an umpire is unsure of the call to be made.

A final thought. While we wait for technology to be used, we should remember that even video footage could result in incorrect decisions. There will always be some statistical error, only a lessor error than those made by human umpires. Fortunately with technology, line calls can not be biased by emotion but only based on whatever video footage is available. With this technology even the teams we support will catch a few breaks in the long run.

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