So how “Tennis Serve Tracker” measures tennis serve speed? The fundamental difference is that it processes every single frame in the video feed and recognizes the court on the image frame. It allows to reconstruct 3D world coordinates of the server and ball from the image coordinates. Application provides constant feedback by highlighting court lines, net and a ball on the screen. Now having the time measurements from the video and ball world coordinates application can calculate your serve speed with a great accuracy, most times way better than a commercial speed gun (see doppler effect cosine factor error)!
“Tennis Serve Tracker” is iOS and Android app that measures tennis serve speed using video processing and image recognition technologies. Why is it worth trying it when there are similar apps on market? Because all these apps can be split on 2 categories - first are the ones that do it very, very bad or simply invent measured speed and won’t be mentioned here at all. The others do measure the serve speed, but it’s a lot of manual interactions with setting multiple parameters, like choosing deuce/ad serve type, server height, marking server and ball positions on the standard court image template that has no resemblance to the actual court we see with our eyes. These actions drastically increase an error margin, time and effort required to perform a single serve speed measurement - does it match fast pacing tennis game we all love?
See it for yourself - visit “Demo Videos” page for videos with real time side by side comparison between speed radar gun and the app.