In experiments, the researchers fired a laser beam through a mask — a thick sheet of plastic with slits cut through it in a certain configuration, such as the letter A — and then through a 1.5-cm “tissue phantom,” a slab of material designed to mimic the optical properties of human tissue for purposes of calibrating imaging systems. Light scattered by the tissue phantom was then collected by a high-speed camera, which could measure the light’s time of arrival. (Credit: Camera Culture Group/MIT)

MIT researchers have developed a technique for recovering visual information from light that has scattered because of interactions with the environment — such as passing through human tissue. The technique could lead to medical imaging systems that use visible light, which carries much more information than X-rays or ultrasound waves.

In experiments, the researchers fired a laser beam through a mask — a thick sheet of plastic with slits cut through it in a certain configuration, such as the letter A — and then through a 1.5-cm “tissue phantom,” a slab of material designed to mimic the optical properties of human tissue for purposes of calibrating imaging systems. Light scattered by the tissue phantom was then collected by a high-speed camera, which could measure the light’s time of arrival. From that information, the researchers’ algorithms were able to reconstruct an accurate image of the pattern cut into the mask.

The new system relies on a pulsed laser that emits ultrashort bursts of light, and a high-speed camera that can distinguish the arrival times of different groups of photons, or light particles.

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