  Capillary refill time (CRT) is a method of measuring the peripheral perfusion
status through a visual assessment. We have developed a robust system to
measure CRT using a webcam (RGB) that monitors polarized light reflected on the
skin. The average image intensity changes exponentially in time after the
application of compression. The characteristic time constant we designated
polarized capillary refill time (pCRT). We tested the pCRT performance in
twenty-two healthy adult volunteers with different ages 37 $\pm$ 16, by
momentarily applying a low compression (7 kPa) to the forearm of the
volunteers. Results show positive behavior in conditions including; poor
perfusion, high and low concentration of melanin, anemic conditions, and
damaged skin. In 80% of unique measurements, the result is within $\pm$ 20% of
the expected pCRT.
