Researchers in UC Santa Barbara professor Yasamin Mostofi’s lab have proposed a new foundation that can enable high-quality imaging of still objects with only WiFi signals. Their method uses the Geometrical Theory of Diffraction and the corresponding Keller cones to trace edges of the objects. The technique has also enabled—for the first time—imaging (reading) the English alphabet through walls with WiFi, a task once deemed too difficult for WiFi due to the complex details of the letters.