The VDM system has been the standard measuring system for several IAAF World Championships. It has many advantages over the EDM (laser system) in that the computer saves all of the high definition images of the jump for review, inquiry or protest. As previously mentioned, technicians operate the equipment but trained officials determine the first point of contact for the measurement.
One of the first competitions that it was used was at the 2006 World Indoors in Moscow (back up to the EDM).
I remember Walter Davis had this massive jump but the officials (using the EDM) started to measure a mark from the previous jumper that was not completely cleared. Fortunately the VDM judges got it right and it was the gold medal jump.
In Portland, the cameras were mounted in the ceiling with a clear view of the pit. The system is calibrated in advance by an EDM (there was one permanently stationed near the pit). And there are calibration markers surrounding the pit. The VDM officials in the booth had radio contact with the judge at the board to let them know when the measurement was completed.
High definition is great but the bad news is the viewer gets to see all of the blemishes and in the case of the women's long jump the officials were able to see a mark that officials on the field of play might have missed using other systems. They made the correct call and team officials agreed after seeing the images.
We also had a video system with over 25 real time feeds with two international referees constantly viewing the action.
The IAAF has total transparency when it comes to the competition. Any team coach/manager may view any of the videos before filing a protest.
Just for the books, because of all of the above we had several inquiries over the four days of competition but not one single protest!!!!