Saturday, 23 June 2012

Making the Invisible Visible

It is becoming increasingly evident that computer vision is changing
the way that we are perceiving the world. New research revealed this
week by MIT researchers, shows how computer vision techniques are
enabling us to see the human body in striking new ways. By
amplifying the variations in video footage of human subjects,
imperceptible processes, such as the circulation of blood through
skin, become clearly visible.

This is enabled by new software developed within MIT's Computer
Science and Artificial Intelligence Laboratory by a team comprised of Michael Rubinstein,
Hao-Yu Wu, Eugene Shih, William Freeman, Fredo Durand and John Guttag.

Their software works by magnifying and emphasising colour changes
which occur within video footage. When observing human subjects,
these colour changes correspond to physical processes such as the
beating the of the heart and the inflation of the lungs. But the
software can also be used to analyse other imperceptible phenomena,
such as the movement of a vibrating string.

MIT describe the system as "somewhat akin to the equalizer in a
stereo sound system, which boosts some frequencies and cuts others,
except that the pertinent frequency is the frequency of color changes
in a sequence of video frames, not the frequency of an audio signal."

Researcher, Michael Rubinstein believes the system could be used for "contactless monitoring" of
hospital patients' vital signs. Boosting one set of frequencies would
allow measurement of pulse rates, via subtle changes in skin
coloration; boosting another set of frequencies would allow
monitoring of breathing. The approach could be particularly useful
with infants who are born prematurely or otherwise require early
medical attention. Rubinstein says, "Their bodies are so fragile, you
want to attach as few sensors as possible."