Fig. 1
From: Does training level affect the accuracy of visual assessment of capillary refill time?
Image analysis CRT. The recorded videos were used thereafter in a separate setting to calculate CRT via image software analysis (image analysis CRT). Averaged color of the fingernail area was extracted from the digital video file and the color change was represented as RGB waveforms. And then, the RGB waveforms were converted to a grayscale waveform. A curve fitting the returning phase of the grayscale waveform was modeled as an exponential decay using the least squares method. The time to achieve 90% return of fitting curve was reported as “image analysis CRT”