raspberry pi + pi noir camera + ir led (940nm) = vein viewer

basically the title say it all
and in less then 3min you can plug it all and get a basic image

i used a 3w 940nm led just cause i had it from another project but i guess that most kind of nir leds will get the job done as far as they in between 940nm - 740nm

you can get the leds from here for example but any other place is just as good if not better
aliexpress 850nm 3w leds

then all you need is just a noir raspberry pi camera like this one CLICK HERE

with my application i used about 15 degrees angle between the ir led light source and the camera

you can use this excellent guide for operating your raspberry pi camera with opencv
CLICK HERE FOR THE CODE GUIDE 

you can then take it further with opencv with basic equalize histogram or even add a nano/micro laser/led projector and project the image on your hand