The Rise of Computer Vision: A Modern Alternative to Baseball Radar Guns
A radar gun measures speed with radio waves and the Doppler effect. Computer vision does it with cameras and software that track the ball frame by frame. At the top level of baseball, cameras have already taken over: MLB's Statcast now runs on Hawk-Eye camera tracking.
How computer vision measures a pitch
- Cameras capture video of the ball's flight at a high frame rate.
- Software finds the ball in each frame.
- Calibration maps pixels to real-world distances, so the system knows where the ball is on the field.
- Speed comes from position over time. If the ball moves a known distance between frames, and the frames are a known time apart, that's the speed.
- Multiple cameras let the system work in 3D, tracking trajectory, release point and movement, and in high-end systems, spin.
Computer vision vs radar guns
| Radar gun | Computer vision | |
|---|---|---|
| What it measures | Speed (some guns add spin) | Speed, trajectory, movement, release point, sometimes spin |
| Setup | Point and shoot | Cameras must be placed and calibrated |
| Lighting | Doesn't matter | Needs good, even light |
| Angle | Reads low if you're off-line | Corrects for angle when calibrated |
| Cost | Wide range, from budget guns to pro models | Phone apps are cheap; pro systems are expensive |
What to watch for
- Frame rate and resolution. A fast ball can blur or jump between frames. Higher frame rates help.
- Lighting. Shadows, glare and dim light can confuse tracking.
- Calibration. If the system doesn't know distances accurately, speeds will be off.
- Processing time. Some setups give instant results; others take a moment.
- Weather. Rain and fog can interfere with cameras.
Where you'll see it
- MLB: Hawk-Eye cameras power Statcast in every park.
- Training facilities and colleges: camera-based and radar-based trackers sit side by side.
- Phone apps: some apps estimate pitch speed from video. Results vary with the phone, frame rate and setup; we compare them in radar gun apps vs real radar guns.
You can try the basic idea yourself with slow-motion video and a bit of math; see how do I measure pitch speed?
Will cameras replace radar guns?
At the pro level, largely, for official data. But for a coach at practice or a parent at a game, a radar gun is still the fastest, simplest way to get a reliable speed: no setup, no lighting worries, an answer in a second. Expect the two to keep living side by side, with apps and cameras getting better and cheaper.
For the bigger picture, see the evolution of baseball radar guns.
Prefer a simple, reliable reading? See our guide to the best baseball radar guns →
FAQ
Is computer vision more accurate than a radar gun?
A well-calibrated multi-camera system can be very accurate and gives much more data, like spin and movement. A single phone camera is usually less reliable than a good radar gun for speed.
What does MLB use to measure pitch speed?
MLB's Statcast uses Hawk-Eye camera tracking in every ballpark. Before that, Statcast's pitch tracking used TrackMan radar.