Hot Spot, Snickometer, and Hawk-Eye: The Technology That Changed the Ashes
How the bundle of broadcast and DRS technologies transformed Ashes cricket — the origins of HotSpot thermal imaging for edge detection, the Snickometer and UltraEdge for sound cue analysis, Hawk-Eye for ball tracking, the 2009 Ashes as the first full DRS series, memorable technology controversies, and whether these technologies have made the game fairer.
HotSpot: Seeing the Invisible Edge
HotSpot is an infrared imaging system developed by BBG Sports (Australian company) that detects heat generated by friction when the ball makes contact with the bat edge, pad, or body. Two infrared cameras positioned at either end of the ground capture a continuous thermal image of the batsman and ball. When ball contacts a surface, friction generates a localised heat signature that appears as a bright spot on the thermal image. This heat mark persists for approximately 1-2 seconds, allowing frame-by-frame replay to confirm whether ball-to-bat contact occurred at the edge of the bat (a catch) or whether the ball missed the bat and struck the pad.
HotSpot became central to Ashes controversies because it can definitively confirm or deny edges that are ambiguous to the naked eye and even to standard broadcast cameras. The 2013 Ashes produced the most celebrated HotSpot controversy: Stuart Broad was not given out by the on-field umpire after the ball clearly deviated off his bat — Broad chose not to walk (waiting for DRS review), but Australia did not review in time. HotSpot subsequently confirmed the edge. Broad's non-walking became one of the most discussed sportsmanship debates in modern cricket.
Snickometer and UltraEdge
The Snickometer (invented by British computer scientist Allan Plaskett in the 1990s) is a broadcast tool that analyses the audio captured by the stump microphone and correlates it with the video frames. When a ball passes the bat, a 'snick' (the distinctive sound of ball-on-bat contact) appears as a spike in the audio waveform at the same frame that the ball passes the edge. The Snickometer was originally a broadcast analysis tool (not used for DRS decisions) — it gave viewers at home the impression of knowing the answer while the umpires on the field did not have access to the same information.
UltraEdge (developed by Hawk-Eye Innovations, who supply the DRS technology) is the DRS-grade evolution of the Snickometer concept — more sensitive microphones, better synchronisation with camera frame data, and faster processing for real-time DRS decisions rather than broadcast review. UltraEdge synchronises the audio waveform with the ball's position from multiple cameras, making it easier to distinguish a ball-bat contact spike from background noise (crowd noise, bat touching the pitch, equipment sounds). UltraEdge is the system shown to the third umpire during DRS reviews — the Snickometer remains a broadcast tool for viewer entertainment.
The Technology Package in DRS
In a DRS review, the third umpire uses a specific sequence of technologies: first, the decision type determines which system to consult. For a caught-behind or caught-at-slip: UltraEdge (audio spike) and HotSpot (heat mark) are reviewed. For an LBW: Hawk-Eye ball-tracking is the primary system. For a run-out or stumping: frame-by-frame video at the available frame rate. These systems are used in combination — an LBW review always includes both the delivery path (did the ball hit the pads?) and a HotSpot check (did the ball hit the bat first, which would invalidate the LBW?). The third umpire synthesises all available evidence before signalling their decision.
Frequently asked questions
Can teams challenge the technology results in DRS?
No — the third umpire's decision based on DRS technology is final. Neither team's captain nor the on-field umpires can challenge the third umpire's ruling once communicated. If a team believes a technology system was malfunctioning (e.g., HotSpot cameras were offline), they may raise the concern through the match referee, but this cannot reverse an in-match decision. The match referee has authority to investigate technology failures after the match and could, in theory, raise the issue with the ICC — but no in-match decision has ever been formally reversed on technology-malfunction grounds.
Why doesn't HotSpot always show a mark even when the ball clearly hit the bat?
HotSpot requires sufficient friction at the contact point to generate a detectable heat signature. Very faint glancing edges (where the ball barely clips the bat's outer edge with minimal lateral force) may generate too little friction for the infrared camera to detect against the thermal background of the bat and environment. Cold weather also makes HotSpot less reliable — the temperature differential between the bat and environment is smaller in cold conditions, making faint heat marks harder to distinguish. This is why cold-weather Ashes Tests in England have produced HotSpot controversies that would not occur in warm-weather Tests in Australia.
Are all international teams required to use DRS?
No — DRS participation by touring teams is optional in bilateral series, though the ICC has moved toward making DRS mandatory for all ICC-sanctioned international matches. India was famously resistant to DRS for many years (2009-2016), citing concerns about the technology's accuracy and their board's desire to retain traditional umpiring authority. India finally accepted DRS for bilateral series from 2016 onward. ICC events (World Cups, ICC championships) mandate DRS. The remaining question is whether domestic and associate member nations have the infrastructure and budget to provide DRS, which remains a cost and logistics barrier.