Postings

Posted on March 28, 2002 at 15:46:58:

Have you seen Shot Spot, the new line calling feature on ESPN's tennis broadcasts? ESPN has 10 cameras around the court on each line that tie in with a computer program which shows where the balls land. The system is extremely accurate and makes the questioning of close calls a lot more interesting. Shot Spot also records serve locations and speeds and can show tendencies for the players' serves. While this system isn't ready to replace linesmen, what if players got a couple of replay requests each set to check a questionable call?

Can someone tell me where I can find information about ESPN's shot spot (the 10 cameras they use to generate a computer graphic of where the ball lands on the court) thanks

Posted on June 06, 2002 at 19:13:04:

In Reply to: shot spot posted by mike scaturro on June 05, 2002 at 23:15:41:

I am very skeptical (not cynical) of this system. How was it calibrated and verified. Why are the comentators so confidence in this system. How many cameras are actually used in the computation? As an engineer I would like to know more about this system.

In Reply to: Re: shot spot posted by Ian on June 06, 2002 at 19:13:04:

I completely agree with you. The commentators won't describe how the system works, and they take its results as absolute truth. During the French Open, one of them said (paraphrased) "the system is accurate to within a couple of millimeters". That's a bold statement. I've sent a couple of emails to ESPN, but have not gotten a response. I'm skeptical and cynical, but if it works, man is it cool!

Posted on November 11, 2002 at 08:01:12:

In Reply to: Shot Spot posted by tennisfax on March 28, 2002 at 15:46:58:

I would like to know how "Shot Spot" translates the camera image into a mark on the court screen. Any help is appreciated. Thanks Scott Rubinstein

In Reply to: Re: Re: shot spot posted by Tony on June 20, 2002 at 13:23:00:

Yes, I too would love to learn more about ESPN's "Shot Spot" technology. I have become very skeptical while watching the 2002 year-end Masters Cup Championships being played in China. Several times they have shown the elliptical "ball mark", and it has been going the wrong direction campared to the angle that the ball was hit. Another time they showed an elliptical mark for a ball that practically fell straight down, which should have left a round mark. It seems like they use the same ball mark all the time, maybe it quicker instead of having the computer generate a new graphic each time, but if that's the case, how can it be accurate within millimeters ??

Posted on January 22, 2003 at 15:57:26:

ESPN Shot Spot

I may be wrong but in watching the Roddick - El Aynaoui match - in the fifth set with the score 10-9, 15-15, the coverage showed two ways of showing the deciding shot. I think the conventional camera angle showed the ball out and the Shot Spot then showed it in. In any event, I think the two techniques were in discrepancy. The conventional camera coverage was only on for a moment but it was in slow motion. Can anyone double check this possible discrepancy?

Hi, I think the ESPN Shot Spot totally stinks. Why would anyone use such a device? Who would believe it? When you watch it in action, some artist could've decided whether the ball was in or out first and drawn it accordingly. Or the artist could've been sympathetic towards the line judges and drawn the results to match theirs and say "see, they were indeed right". What piece of crap. Bring back the Mac Cam! This is obviously the best device to clearly determine whether the ball was in or out. It shows the actual video of the shot. And you can't fake these images like you can with the Shot Spot. I'm always amazed at why the Mac Cam wasn't used more often. And it seems that it has been replaced by the Shot Spot which upsets me even more. How could a device like the Mac Cam that's so obviously successful at determining line calls be replaced by something that's so questionable as the Shot Spot? I mean, wouldn't you rather see actual photos of the shot rather than an artist's rendering of it? Which would you believe more? Ken

Posted on July 4, 2003 at 9:32:00:

Shot Spot a trajectories

I, too, was very interested in learning more about this new tracking system. I havenÕt seen anything else on it. Has anyone inquired directly of ESPN? The only thing that this sounds like is the military software that has been developed (about 10 years ago) for tracking sniperÕs bullets. I am guessing that if nobody is taking credit for the shot spot technology, then it has something to do with his sort of thing. If there are ten cameras and they can digitize the ballÕs trajectory then they probably plot a trajectory for the ball. It is very possible to do. The only thing that I would question is the way the ballÕs shape gets distorted. This would make a big difference on the very close calls. Nevertheless, this is the first time IÕve actually seen a description of this technology Regards,

Hi, I think the ESPN Shot Spot totally stinks. Why would anyone use such a device? Who would believe it? When you watch it in action, some artist could've decided whether the ball was in or out first and drawn it accordingly. Or the artist could've been sympathetic towards the line judges and drawn the results to match theirs and say "see, they were indeed right". What piece of crap. Bring back the Mac Cam! This is obviously the best device to clearly determine whether the ball was in or out. It shows the actual video of the shot. And you can't fake these images like you can with the Shot Spot. I'm always amazed at why the Mac Cam wasn't used more often. And it seems that it has been replaced by the Shot Spot which upsets me even more. How could a device like the Mac Cam that's so obviously successful at determining line calls be replaced by something that's so questionable as the Shot Spot? I mean, wouldn't you rather see actual photos of the shot rather than an artist's rendering of it? Which would you believe more? Ken

Posted on October 19, 2003 at 21:06:42:

Kenneth, I agree that the Mac Cam is better, but it's expensive technology. That's why you don't see more often and if you think about it, the only place it gets used is on the baseline at the US Open. It uses a high speed video camera that runs at 800 frames per second as opposed to 24 or 30 frames for normal film or video. To use it as effectively as Shot Spot to cover the whole court, you would need 10 Mac Cams. That costs way more than 4 normal video cameras (or even than the first geneation SS system with 10 cameras) which are hooked to a computer running software. And it's much easier to operate than trying to jockey a video tape deck back and forth. Shot Spot is here to stay (or some variation). And the things that they can track now with it is amazing. Like showing where all the serves landed, where the returner is hitting the ball and eve how high of the court they hit each ball, and much more. Get used to it, I predict that within 5 years it will be used to aid the umpire with close call disputes and that within 10 years it will just be the umpire and the Shot Spot making all the calls and no line persons. Frank

KENNETH: How can you say Shot Spot stinks? And the notion that an artist could just draw his/her own trajectory is rather silly. When (not IF) it's implemented on court, it will have been thoroughly tested and proven to be reliable. Also, the Shot Spot can do so many things a Mac Cam can't. With the Mac Cam, you only see the baselines. With Shot Spot's computer simulation, you can see the whole court in 3D, see trajectories of balls, their speed. Now, people can understand the players' strategies, strengths and weaknesses. The viewer can truly appreciate the players' talent, and the differences between players. I think that, as a viewer, it's also a great learning tool to improve your game strategy. After the women's Australian Open final, when Clijsters got a bad call at 4-3 (break point on her serve) in the 3rd set, and was broken and went down 5-3 rather than back at deuce to try to make it 4-4, I suspect there will be more pressure than ever to implement this technology on court. What they're currently talking about is that the chair umpire would have access to instant replays from his/her chair, and would only refer to it when asked by the players. Each player would have two chances per set to question a call. If they're right, they don't use up one of their two chances. From what I heard, I think that alot of people are for it, and now it's more of a question of the logistics, and validating the accuracy of Shot Spot.

FRANK: (RE: Nov 17 2002) You mentionned that the elliptical shape of the mark on the ground made by Shot Spot was sometimes wrong, based on the trajectory of the ball. I'm not sure, but I think the shape of the ball upon impact with the ground also depends on the SPIN of the ball. Even if a ball is coming almost vertically, once it hits the ground it will deviate from the "vertical" trajectory if it has spin on it, making an elliptical mark. Don't quote me on this, but it makes sense to me.

(RE: Oct 19 2003) I would be very surprised if Shot Spot replaced linespeople. Tennis, although continuously evolving, is a sport that values tradition. Linespeople are one thing that makes tennis unique, it is a core element of tennis. And as far as I know, they're all volunteers, so it's not like the tournaments would be saving money by removing them. That's just my two-cents worth...

Posted on March 20, 2004 at 06:22:00:

Tennis Week: We're seeing you show the speed of the players' strokes, as has been done with the serves for years, what's the technology behind that?

Dennis Deninger, ESPN Coordinating Producer: It's the same technology that we use for our shot spot. There are five cameras placed strategically around the court, up and looking down on the court, say like in the mezzanine level. Those five cameras triangulate the speed and positioning for the display of the shot spot as well as we can show the speed of the ball at any point in its flight. You know the serve may have left the racquet at 110 mph, it hits the ground at about 80 mph and then it bounces at about 50 or 60 mph as it reaches the returner's racquet. And if the returner smacks it harder back, we can tell you that as well. It's a remarkable system. It stores the speed of the ball at every point of its flight for the entire match.