HotSpot in Cricket — Infrared Technology for Edge Detection
HotSpot uses infrared cameras to detect whether the ball has hit the bat or pad. Learn how it works, its limitations, and when it is used in DRS.
What Is HotSpot?
HotSpot is an infrared imaging system used in cricket to detect whether the ball has touched the bat, pad, glove, or ground. The system uses two infrared cameras positioned at each end of the ground. These cameras detect the friction-generated heat that occurs when the ball makes contact — producing a white 'hot spot' on the image where contact was made.
How It Works
When the cricket ball strikes any surface at speed, friction generates a small amount of heat at the point of contact. Infrared cameras sensitive enough to detect minute temperature differences (fractions of a degree) capture this heat signature. When played back in slow motion, a bright white spot appears where the ball made contact — revealing whether it struck the bat, the pad, or the glove.
Limitations of HotSpot
- Thin edges — very fine edges generate minimal heat that can be below the detection threshold of the camera.
- Weather conditions — extreme cold reduces friction heat; extreme heat raises baseline temperatures, reducing contrast.
- Image timing — HotSpot must be reviewed at precisely the right frame to catch the contact; reviewing too late means the heat has dissipated.
- Previous contact heat — residual heat from an earlier delivery on the same area of the bat can create false positives.
- Not universally available — HotSpot is expensive to operate and is not used in all international matches, only in select series where providers have arranged it.
HotSpot vs Ultra-Edge (Snickometer)
HotSpot detects edge through heat; Ultra-Edge (the modern Snickometer) detects edge through sound. Both are used in DRS reviews but as complementary, not competing, technologies. If HotSpot shows no spot but Ultra-Edge shows a sound spike at the moment of ball contact, there may have been contact. The third umpire considers the weight of evidence from all available technology.
Frequently asked questions
Is HotSpot always used in DRS?
No — HotSpot is available in some series but not others, depending on whether the broadcast provider has contracted for it. The ICC requires DRS for international matches, but some DRS components (HotSpot specifically) are optional; not all cricket boards have insisted on its inclusion in every series.
Can beeswax on a bat trick HotSpot?
In 2013, allegations arose that some players applied beeswax to the face of the bat to reduce friction and prevent HotSpot from detecting edges. This controversy prompted debate about the technology's susceptibility to countermeasures, though the ICC found no conclusive evidence of systematic abuse.