Hot Spot Technology in Cricket Explained
What Hot Spot does, how infrared imaging detects bat-ball contact, and when it is used in DRS reviews.
What Is Hot Spot?
Hot Spot is an infrared imaging technology used in cricket's Decision Review System to determine whether the ball has made contact with the bat or pad. Two high-speed infrared cameras are mounted at either end of the ground. When the ball rubs against any surface — bat, pad, glove or even body — it generates friction heat. Hot Spot images this heat as a bright spot on a dark thermal frame, revealing contact that is invisible to the naked eye and not always audible on a stump microphone.
How Hot Spot Works
- Two infrared cameras continuously film the batter from both ends
- Thermal images are compared between two consecutive frames — before and after the ball passes the bat
- Any difference in thermal signature reveals contact — a bright 'hot spot' on the bat face, edge, pad, or glove
- The TV umpire reviews the frames and calls for as many frames as needed around the moment of delivery
Limitations of Hot Spot
Hot Spot is highly reliable but not infallible. Thin edges — particularly when the ball barely brushes the outer edge — can produce a hot spot so faint it is below the resolution threshold of the camera. Wet or cold conditions reduce the thermal differential, making faint edges harder to detect. This is why Hot Spot is used alongside Ultra Edge (a waveform audio signal from the stump microphone), not instead of it.
Hot Spot in the DRS Process
When a caught-behind or LBW referral is reviewed, the TV umpire checks the ball-tracking data first for LBW decisions, then reviews Hot Spot and Ultra Edge for any bat contact. If Hot Spot shows a clear spot on the bat or glove, the 'not out' decision is typically upheld (bat before pad). If Hot Spot is inconclusive, Ultra Edge waveforms provide the secondary check. Both together give the TV umpire maximum confidence in the final call.
Frequently asked questions
Can Hot Spot confirm an LBW dismissal?
It confirms or denies bat contact, which is crucial for LBW. If Hot Spot shows the ball hit the bat before the pad, it is not out regardless of the ball-tracking outcome.
Is Hot Spot available in the IPL?
Yes, since the BCCI added DRS to the IPL in 2018 after pressure from players and broadcasters. The full DRS suite including Hot Spot is available at major IPL venues.
Why did Hot Spot miss the famous 2013 Ashes catch controversy?
Stuart Broad's controversial not-out involved an extremely thin edge that produced a faint hot spot below the sensitivity threshold. It highlighted that Hot Spot is a high but not perfect detection system.