It mainly uses the structure of venous blood vessels for identity recognition. Because the venous network contains a lot of characteristic information, it can be used as the object of verification. The principle of palm vein recognition is also to use the different absorption characteristics of vein blood vessels and musculoskeletal to carry out vein angiography. Same principle as palm vein recognition. Because the palm is thick, infrared light can't be transmitted generally, so reflection radiography can only be used. When infrared light irradiates the back of the hand, the part with veins absorbs infrared light, and the reflection is dim, while the reflection of muscles and bones is strong, thus realizing vein angiography. Veins are difficult to forge in the human body,

Vein recognition is a new infrared biometric technology, which absorbs near infrared or human radiation according to deoxyhemoglobin in venous blood.

According to the characteristics of far infrared rays, the vein distribution map of the back of hand (or the back of finger, the belly of finger, palm and wrist) is photographed by an infrared camera with a corresponding wavelength range. After preprocessing such as normalization and denoising, filtering enhancement, vein line segmentation and thinning repair are carried out, and then its features are extracted, and then matched with the feature data pre-registered in the database or stored on the I C card to determine the personal identity [1].

Simply put, it is a higher-end personal identification method than fingerprint identification, which directly tells you that it is not feasible to find the gunman.