MIT Researchers Develop Method to Capture Images Using Ambient Light Sensor

Despite potential privacy concerns, the slow image generation process makes it an unattractive attack vector for hackers.

Researchers at MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed a method of capturing images using only the ambient light sensor found on most mobile devices and many laptops.
The process uses a physics principle called Helmholtz reciprocity, which allows computer algorithms to reverse the sensor data to create an image from the light source's point of view.
The technique created low-resolution images that were clear enough to show gestures like two-finger scrolling or three-finger pinching.
The sensor can only record one pixel at a time, so it takes 1024 passes to create one 32x32 image. This means it takes 3.3 minutes to generate an image using a static black-and-white pattern.
Despite the potential privacy threat, the method is currently too slow to be an attractive attack vector for hackers.