The Economist:

WHEN aliens seize and torture Dr McCoy in “The Empath”, an episode of the science-fiction series “Star Trek”, Captain Kirk and Mr Spock rush to his aid. They are able to assess his condition in seconds with the help of a medical tricorder—a hand-held computer with a detachable sensor that is normally used by Dr McCoy himself to diagnose others. A quick scan with the tricorder indicates that he suffers from “severe heart damage; signs of congestion in both lungs; evidence of massive circulatory collapse”.

Along with teleportation, speech-driven computers and hand-held wireless communicators that flip open, the medical tricorder was one of many imaginary future technologies featured in “Star Trek”. Ever since, researchers have dreamed of developing a hand-held medical scanner that can take readings from a patient and then diagnose various conditions. Now, nearly five decades after “Star Trek” made its debut in 1966, the dream is finally edging closer to reality.

The Economist:

LETTUCE is California’s main vegetable crop. The state grew $1.6 billion-worth of the leafy plant in 2010 and accounts for more than 70% of all lettuce grown in America—itself the world’s second-biggest exporter of the stuff. It is a fiddly business. As well as having to be fertilised and weeded, lettuce must also be “thinned” so that good plants do not grow too close to each other, inhibiting growth. Much of this is still done by hand. Labourers, who tend to be paid per acre, not per hour, have little incentive to pay close attention to what they pull from the ground, often leading to unnecessary waste.

Enter Lettuce Bot, the brainchild of two Stanford-trained engineers, Jorge Heraud and Lee Redden. Their diligent robotic labourer, pulled behind a tractor, starts by taking pictures of passing plants. Computer-vision algorithms devised by Mr Redden compare these to a database of more than a million images, taken from different angles against different backdrops of soil and other plants, that he and Mr Heraud have amassed from their visits to lettuce farms. A simple shield blocks out the Californian sun to prevent odd shading from confounding the software.