While it's often important for doctors to monitor a patient's physical activity throughout the day, placing cameras in that person's home is a pretty obtrusive way of doing so. Scientists have now developed an alternative, in the form of activity-tracking pants.
Created by Prof. Arnaldo Leal-Junior and colleagues at Brazil's Federal University of Espirito Santo, the POF (polymer optical fiber) Smart Pants incorporate two 1-mm-thick optical fibers which run vertically along the back of each leg.
At 30 points along each fiber, a small length of the cladding has been removed. The cladding is the outer layer of an optical fiber, and it has a lower refractive index that the light-carrying core. Therefore, as light travels through bends in the fiber, the reflective cladding/core boundary keeps that light confined to the core, maintaining a strong signal.
In the Smart Pants, the fibers bend as the wearer moves around throughout the day. And wherever they do bend, some light escapes from the cladding-free points in that area. This causes the total strength of the optical signal to drop – the degree to which it does drop corresponds to certain known activities.
So, by continuously monitoring the strength of the signal as it reaches the end of each fiber, a machine-learning algorithm on a linked microprocessor is able to determine what the person is doing. In lab tests, the technology was 100% accurate at identifying actions that included walking, fast walking, squatting, sitting on a chair, sitting on the floor, front kicking and back kicking.
The scientists are now working on connecting the Smart Pants' processor to the cloud, so that physicians will be able to remotely monitor their patients. A paper on the research was recently published in the journal Biomedical Optics Express.
"Our polymer optical fiber smart pants can be used to detect activities such as sitting, squatting, walking or kicking without inhibiting natural movements," said Leal-Junior. "This approach avoids the privacy issues that come with image-based systems and could be useful for monitoring aging patients at home or measuring parameters such as range of motion in rehabilitation clinics."
Source: Optica
