Stanford University researchers have recently developed a technique for keyhole imaging. The new emerging technology is known as non-line-of-sight imaging and tracking or NLOS. In this technique, with the use of transient time-of-flight measurements and scattered light, the shape position of objects around corners and behind various diffusers can be discovered.
The technology available nowadays for NLOS imaging, is having imaging hardware to scan a large area of the surface that is visible for indirect paths. NLOS imaging may sound like science fiction, but in reality, when we come to its functional aspect it could have applications in autonomous driving as well as other scenarios. So, by the new keyhole imaging technique put forwarded by Standford researchers, a sequence of transient measurements using a single optical path can be captured.
Now coming to the naming of the technique, it is named keyhole imaging because the single light path used here is small enough to pass through a keyhole into the room. If some hidden object moves inside the room in the course of imaging acquisition time, the technology can capture time-resolved projections of the shape of the hidden object. Keyhole imaging technology would be really useful for police and military in determining what is inside a room before they enter into it.
Stanford’s system works with a time-resolved detector and a pulsed laser that is used for illuminating an image point inside the room that is visible through the keyhole. The laser beam is used for scattering the light through the keyhole and it will hit on a hidden target. This scattered light is further used by the time-resolved measurement portion of the imaging system for reconstructing shapes of objects within the room.
As a part of testing the technique, Stanford researchers obtained a rough hidden shape of a mannequin and letters at the side of the beam of light used by the imaging system. One of the limitations of the technique is that keyholes aren’t common nowadays. So, it limits the possibility of using the system for imaging inside unopened rooms. On the other hand, the technology will help autonomous cars to see what is around corners.