BACKSCATTER X-RAYS, which reveal ceramic knives and explosives that metal detectors miss, are due to be rolled out in airports this year. But the public didn't like test images that make you look "fat and naked," as the director of the Transportation Security Administration's lab admitted when she saw her own scan (left). So the tsa has instituted a "privacy algorithm" to convert lifelike figures into cartoonish silhouettes (right). But the algorithm also obscures the weapons the scanner was designed to discover. And weapons hidden between folds of skin and fat fool both versions.