Tracking Hidden Objects

Out of sight but not out of mind

The Photon Force PF32 single-photon counting camera can be used to capture triple-scattered light and accurately locate hidden objects.

Detection and tracking of moving objects that are hidden from view

Researchers from the University of Glasgow and Heriot-Watt University teamed up for a research project covering ‘Detection and tracking of moving objects hidden from view’. The team used the Photon Force PF32 SPAD array camera to capture photons that had interacted with an object hidden from direct line of sight.

The team demonstrated a compact non-line-of-sight laser ranging technology that relied on the ability to send light round an obstacle using a scattering floor and then detected the return signal from a hidden object within only a few seconds of acquisition time. The PF32 allowed the team to follow the movement of an object located a metre away from the camera with centimetre precision.

The experimental set up to track hidden objects

a.) The camera Is positioned on the side of the wall and Is looking down at the floor: It cannot see what Is behind the wall but Its field or view Is placed beyond the edge of the obstacle. b.) A side view shows that the target is hidden behind the wall. To see the hidden target around the corner, laser pulses are sent to the floor. c.) The light then scatters off the floor and propagates as a spherical wave behind the obstacle, reaching the hidden object. This light is then in turn scattered back Into the field of view of the camera. The SPAD camera records both spatial and temporal information on the propagating spherical light wave as it passes through the field of view, creating an elliptical pattern where it intercepts the floor. An example of the spatially resolved raw data, as recorded by the camera for a fixed time frame as the ellipse passes In the field of view. Is shown In the Inset.

Watch the video

This video shows how the system can track the hidden object and update the reconstruction every three seconds, ensuring that if it moves, the object is still tracked.

Watch the video

This video shows how the system can track the hidden object and update the reconstruction every three seconds, ensuring that if it moves, the object is still tracked.