Venipuncture is the most common way of all invasive medical procedures. A vein display system can make vein access
easier by capturing the vein information and projecting a visible vein image onto the skin, which is correctly aligned with
the subject’s vein. The existing systems achieve correct alignment by the design of coaxial structure. Such a structure
causes complex optical and mechanical design and big physical dimensions inevitably. In this paper, we design a stereovision-
based vein display system, which consists of a pair of cameras, a DLP projector and a near-infrared light source.
We recover the three-dimensional venous structure from image pair acquired from two near-infrared cameras. Then the
vein image from the viewpoint of projector is generated from the three-dimensional venous structure and projected
exactly onto skin by the DLP projector. Since the stereo cameras get the depth information of vessels, the system can
make sure the alignment of projected veins and the real veins without a coaxial structure. The experiment results prove
that we propose a feasible solution for a portable and low-cost vein display device.