Researchers at MIT Media Lab’s Camera Culture Group have harnessed video game technology to capture clear camera images through windows.
The team used a modified Microsoft Kinect One camera to capture images through glass without the traditional image "overlap" that is often seen. According to the team, a pane of glass produces two reflections that are slightly offset from one another, hence the image overlap. Their system uses light to gauge differences between “the arrival times of light reflected by nearby objects — such as panes of glass — and more distant objects," according to a press release.
“You physically cannot make a camera that picks out multiple reflections,” said Ayush Bhandari, a doctoral student in the MIT Media Lab. “That would mean that you take time slices so fast that [the camera] actually starts to operate at the speed of light, which is technically impossible. So what’s the trick? We use the Fourier transform.”
Put simply, the Fourier transform decomposes a signal into its constituent frequencies, which are characterized by two properties: amplitude and phase. The team notes that conventional light sensors only measure intensity.
In order to navigate this issue, they made targeted measurements that allowed them to reconstruct phase information. From there, in collaboration with Microsoft Research, they created a camera that emits light of specific frequencies and also gauges intensity of reflections.
The team said that this discovery could have implications for noninvasive imaging technologies, like ultrasounds.