Femto Photography May Lead to Around Corner Gun Sight

You may have heard of the Cornershot Gun. The weapon folds in half. Using a video camera scope, the operator can not boldly go where the gun muzzle goes before him. It’s a high tech solution whose price and complexity seems sure to relegate the weapon to a niche role within an urban assault or SWAT team. And so we turn to another approach: Femto Photography. A camera system that records at a trillion frames a second bounces pulses of light off surfaces to map unseen images. Allow its inventors to explain. Oh, but before that, please note that the MIT brains behind the award-winning technology seem to have completely missed the potential ballistic application. Kids . . .

In traditional photography, the speed of light is infinite and does not play a role. In our transient light transport framework, the finite amount of time light takes to travel from one surface to another provides useful information. The key contribution is a computational tool of transient reasoning for the inversion of light transport.

The basic concept of a transient imaging camera can be understood using a simple example of a room with an open door. The goal here is to compute the geometry of the object inside the room by exploiting light reflected off the door. The user directs an ultra short laser beam onto the door and after the first bounce the beam scatters into the room. The light reflects from objects inside the room and again from the door back toward the transient imaging camera.

An ultra-fast array of detectors measures the time profile of the returned signal from multiple positions on the door. We analyze this multi‐path light transport and infer shapes of objects that are in direct sight as well as beyond the line of sight. The analysis of the onsets in the time profile indicates the shape; we call this the inverse geometry problem.

No problem at all—if they can miniaturize the system and mount it on a gun. Unless the students have moral qualms about taking large checks from the industrial military complex for technology that can give American troops and cops a strategic advantage. In theory. Oh, and help surgeons and firefighters. Eventually.