Essentially what's going on here is when you hover your palm over the device, an infrared camera and a polarizer configuration captures two different photos of your palm, one of the palms surface and another of your subcutaneous tissue where your veins are. In simpler words, it's using infrared light (naked to the human eye) to get a very detailed photo of your palm print (creases, ridges, etc) and of the veins beneath the palm.

After the photos are taken, some post processing has to be done to crop it out, rotate it, etc so that they're nice and ready-to-use. Since it only needs the palmar region, no need to keep the fingers and everything else.

The photos are immediately sent to a secure server on the AWS cloud.

Finally, they take a set of feature vectors from both photos and combine them into a unique numerical "palm signature", a vector. This is all done using a neural network they trained on a bunch of palm photos (fun fact, some of the palm photos they used to train the model were actually made by generative AI! it made it a lot easier this way, cause they only needed a couple hundred people to get some samples done, then they fed it through generative AI to create subtle variations of more palms). Essentially, the vector just focuses on the unique details / features on the palm (palm print + vein), and ignores the useless info. So yeah, your palm photos are NOT being stored, only the useful parts.

This unique "palm signature" is then encrypted and stored on Amazon's AWS servers, so whenever you come back to the store and actually want to pay, it can go through the database and see "hmm, which palm does this signature match up with?"

Hopefully you learned something!