How DRS Technology Works

DRS — the Decision Review System — uses three technologies working together. Each one answers a different question.

1) Hawk-Eye: 6–10 high-speed cameras film the ball from different angles and a computer joins the images to track its 3D path at 340 frames per second. This shows where the ball pitched, where it hit the pad, and where it would have gone.

2) UltraEdge (Snickometer): Tiny microphones inside the stumps pick up sound. The system lines up the spike of sound with the slow-motion video to see whether bat (or glove) touched the ball — accurate to a 2 ms window.

3) Hot Spot: An infrared camera shows a bright mark where two surfaces rub — proof that the ball brushed the bat, pad or body.

The 'umpire's call' margin exists because Hawk-Eye is not perfect — it allows for about half a ball's width of uncertainty. If the ball is only just clipping the stumps, the original on-field decision stands.