The team of Associate Professor Rajesh Menom from the University of Utah has developed a technology for passively intercepting light passing through ordinary glass or its equivalent. For example, a lot of interesting things happen behind almost any window, but in order to capture this, we need to put an active device in front of it: a video camera. And the new technology makes it possible to partially circumvent this limitation.
The prototype for Menom's setup looks like this. A simple optical sensor is attached to the end face of a sheet of transparent plexiglass or glass, all opposite faces are pasted over with reflective tape. We turn on a certain image source in front of the glass, for example, an LED panel, on which simple symbols are displayed. 99% of the light falls on the glass at close to right angles and passes on, but 1% is scattered in the thickness of the material and the photons run to the edges of the plate. Here they are reflected from the tape and fall into the receiving window of the sensor.
So far, these are just spots - a special algorithm is needed that converts the light scattered in the glass into the original image, but Menom's team has just finished working on it. The output is a coarse, but recognizable image. That is, it is enough to take a very simple set of accessories and provide a connection to a computer or other computing device in order to turn any window into a video camera.
Menom's team is now working on more powerful sensors and learning to intercept light from weak, non-directional sources. They see the practical application of the technology in automatic surveillance systems - with such a low picture quality, it is necessary to design cameras not for people, but for cars. For example, for situations where it is important to track the very fact of movement in the observation area, without additional energy consumption.