In 2010 Hawk-Eye did produce a more complete description of how it is used at cricket matches.1 It is operated by three people. Hawk-Eye Innovations describes their roles as follows:
- Lining up and calibrating the cameras
- Measuring the pitch and the stumps which do vary from ground to ground
- 1 member of staff is responsible for the virtual reality graphics and offers LBW replays and all the other Hawk-Eye features to the TV director.
- The other 2 members of staff both are responsible for the tracking. They work independently of each other to provide redundancy, but are able to see a comparison of the two tracks. If they are different for any reason, they can be pro-active in working out why rather than being re-active after a LBW appeal. On a ball by ball basis they would do the following:
- (a) hit a button to tell the system that a ball has been bowled and trigger the tracking
- (b) manually fine tune the point on the trajectory where interception with the batsman was made. Automatically the system is only able to determine the interception point to the nearest frame of Hawk-Eye video running at 106 frames per second. This can be improved manually and is the only way to ensure that the interception point is accurate to 5 mm.
- (c) Tune settings to account for varying light conditions.
- (d) Tune settings to deal with camera wobble.
We learn from this that at this time the frame rate was around 100 fps. But what is really interesting is point (b)—the need for manual intervention to maximize accuracy. The remarks about the need for various kinds of fine-tuning are also revealing. This description intimates that the Hawk-Eye system is far less autonomous than we had been given to believe and that there could be scope for mistakes driven by human error. This reinforces the need for a more transparent presentation of how these devices work and, especially, the extent to which there was or was not manual intervention in their early history.