At FutureMed, professor Ramesh Raskar at MIT’s Media Lab shed light on imaging technology that is so fast that it can be used to create slow-motion video of light in motion. Impressively, the imaging modality also can see around corners. That capability could expand the power of medical applications such as endoscopy, where it could enable the imaging of irregular surfaces within the heart or locate hidden polyps in the colon.
The camera works by sending a series of incredibly short laser pulses at a visible target. Some of the photons in the laser packets scatter, eventually reaching areas that are invisible from the camera’s line of sight. A tiny fraction of those photons bounce back and return to the camera. “The key is that they reach the camera at a slightly different time slot,” Ramesh explains. “Because the camera can sample the world at a trillion frames per second, we can analyze these photons that arrive slightly later. We will piece that information together, very much like you would in a CT scan machine.” That analysis enables them to see around corners. Ultimately, it could be used to create “diagnostic visualization tools that are not really invasive,” he says. The modality could also be integrated with MRI and CT imaging, he says.
To achieve this imaging feat, the researchers had to create femto-photography sensors capable of imaging at one trillion frames per second. One second of recording at that resolution generates roughly one petabyte of data.
Low-Cost Mobile Medical Devices for the Third World (and Beyond)
Raskar’s researchers have also developed a technology known as EyeNETRA (Near-Eye Tool for Refractive Assessment). The device is a snap-on eye piece that goes on top of a phone. “You look into it, click on a few buttons to align it, and it does some calculations and gives you data for a prescription of your eyeglasses,” he says. “Whether it is nearsightedness, farsightedness, or astigmatism, the measurements are better than that $10,000 or $20,000 refractors. “And plus you can do it anytime you want and as a bonus, you can also scan for cataracts.”
|The NETRA technology shown in a clinical trials in Hyderabad, India. The $2 clip-on device works in a similar fashion to expensive laser-based Shack-Hartmann wavefront aberrometers used in optometry.|