Key components of the imaging system: (a) cross-sectional illustration of a rodent tail anatomy, (b) front (i) and side (ii) views of the imaging unit, with labeled camera angles, and (c) NIR tail vein imaging and segmentation. Image acquired under visible light (i), corresponding image acquired with the NIR imaging system using the transillumination method (ii), and tail vein segmentation applied to the NIR image (iii).