Figure 1
From: Automated processing of thermal imaging to detect COVID-19

Thermal image processing. The raw thermal images are displayed in HC-Rainbow scale. Displayed are representative images of the different stages of our image processing algorithms for the fractal dimension (FD) of the gradient (left) and the “sum of extrema” (SX) in the image (right). For this display the gradient range [-8, 8] was normalized to [0, 255]. All gradient values outside of this range were shifted to its edges before normalization. Full details on image processing algorithms are provided in the Methods section. ROI region of interest.