Hawk-eye is a tool based on military technology, developed by DERA, the Defence Evaluation and Research Agency. It is used by the Channel 4 cricket team to follow the ball's progress through the air, and then display a projected continuation of its flightpath once it has hit a pad or some other obstruction. The best thing about this is the availability of an objective decision on the notoriously subjective LBW rule. Hawk-eye can allegedly determine precisely whether or not a player's stumps would have been struck.
The controversy over Hawk-eye is whether this tool should be made available to umpires in the field, or even Thrid umpires. Television viewers can now watch umpires make incorect decisions, and know that they are incorrect. The presence of this technology serves only to undermine umpires, and remove general confidence in them, as is the case to a lesser extent with slow-motion replays. The human/electronic judgment debate is still raging on in cricket, and unfortunately purists have held sway in the UK for a while. The radical restructuring of the league system that took place, and Malcolm Fletcher's managment of the England side both bode well for a progressionist future. There has been a vast improvement in cricket in the country since the Illingworth years of traditionalism not so long ago. Hopefully Hawk-eye will be fully approved and incorporated before we host the next Ashes.
The official information from www.cricket4.com -Channel 4's cricket site- on Hawk-eye:
We use six cameras strategically placed around the ground to follow every ball in flight, tracking it accurately from the moment it leaves the bowler's hand.
The resulting 3D images are then processed, taking into account swing, variable bounce, trajectory and deviation to determine exactly what each player is doing, and also how each team uses specific tactics to get key opposition players out.
Go and have a play with the very exciting graphic statistics about every ball bowled this last Ashes series! Available here:
http://www.cricket4.com/analyst/hawkeye/advanced.html
Thanks to Teirasias for his help.