A device and method is provided for quickly and accurately determining the size and shape of a human extremity such as a foot by projecting light around a periphery of the extremity and capturing an image of the illuminated foot through a transparent plate. Various embodiments contemplate using light having a wavelength in the near-infrared range to reduce contrast problems caused by dyes used in socks and skin tone problems created by highly pigmented individuals. An image of the foot is digitized and stored in a computer memory in both an illuminated state and a non-illuminated state, and the two images are subtracted. Additional image processing steps on the subtracted image result in various measurement quantities such as foot length, width, arch length, heel width, and arch height.