A standard response to photographs of UFOs, ghosts and other unexplained phenomena is: “It’s just a reflection.” That may soon change. A new camera can remove that doubt by identifying and removing reflections from digital photographs.
The brains at MIT – specifically, researchers at MIT’s Media Lab – started with the idea that it might be possible to take multiple superfast shots of the same image which will show slight differences in the reflection that a computer could detect and remove. Ayush Bhandari, MIT PhD student and study author, said this is impossible.
You physically cannot make a camera that picks out multiple reflections. 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.
The what? In simple terms, the Fourier transform is a way to deconstruct a signal or function of time into the frequencies that make it up – in this case, amplitude and phase. This is a substantial improvement over using conventional light sensors which only measure a light’s intensity.
Being MIT geeks, Bhandari and his team created their reflection-removing camera by hacking a Microsoft Xbox Kinect – a camera for the Xbox 360. Being students at a university that doesn’t want to be sued, they then notified Microsoft Research, which helped with the project.
The researchers first shined light through a window at objects and measured the arrival times of light reflected by the glass and the objects. Microsoft showed them how to modify the Kinect to use only certain frequencies of light and how to measure the intensity of reflections. Throw in a Nobel prize-winning phase retrieval algorithm and voila …
The researchers developed a special camera that emits light only of specific frequencies and gauges the intensity of the reflections. That information, coupled with knowledge of the number of different reflectors positioned between the camera and the scene of interest, enables the researchers’ algorithms to deduce the phase of the returning light and separate out signals from different depths.
The camera needed to measure 45 frequencies to eliminate the reflection, which took a full minute of exposure time. But it worked and it used an off-the-shelf camera. Experts analyzing the results predict the time will be reduced and the technology improved and probably incorporated into some consumer camera products.
What does this mean for UFO, ghost and paranormal photographers? Eliminating the skeptical “It’s just a reflection” response will bring them one step closer to legitimacy.
Are the shelves empty of Kinects yet?