The camera focuses on the small, white circle. The robot sizes up its target, then an arm extends downwards until the suction cup on the end is pressed against the helpless mushroom.
It is captured with a deft bend and twist. The arm retracts and two plastic fingers hold it as whirling blades remove its stalk. It is then dropped into a waiting tray.
All this in six and a half seconds.
Scientists at the Silsoe Research Institute near Bedford have built the working robotic harvester, hoping to revolutionise the mushroom industry.
In trials in the UK and Holland, the robot averaged more than an 80 per cent pick success rate, although at half the speed of a human.
Mushrooms grow randomly, and machine vision and image analysis programming on a basic PC allows the robot to select individuals of appropriate size.
Another program analyses the pattern of surrounding mushrooms - they often grow bunched together - so they can be picked in the right order.
The delicate crop is handled with great care by pliable, polyurethane fingers that adjust their grip, ensuring little damage and no contamination.
Simon Miles, a member of the development team, said: "The quality of the mushrooms picked was better than by humans - the farmers were pleased about that."
The robot's genesis is described in the Journal of Agricultural Engineering Research.