Fingerprint recognition is currently the most widely used method of smart locks. Punch cards to and from get off work, unlock mobile phones, unlock doors, etc. So how is the fingerprint recognition function of the smart fingerprint door lock realized?

With the continuous development and maturity of fingerprint recognition technology, door locks also use fingerprint recognition technology, and smart fingerprint door locks have been born since then. The smart door lock significantly improves the security and convenience of the door lock by applying the fingerprint recognition function. How is the fingerprint recognition function of the fingerprint door lock realized?

The so-called fingerprint refers to the lines on the surface of the fingertips of the human body. The fingerprint recognition mainly has the following three processes:

1. Fingerprint enhancement:

In the process of fingerprint collection, due to various reasons, the collected fingerprint image inevitably introduces some noise. If it is directly used for fingerprint identification, it is often difficult to achieve good results. Therefore, we can improve the quality of fingerprint images through certain image enhancement techniques. The techniques used here include image segmentation, histogram equalization, filter enhancement, binarization, and thinning.

2. Feature extraction:

Fingerprint is a biological feature of the human body, which is "unique" and "unreproducible". The fingerprint collector will compare the fingerprints in normal use after collecting them.

 3. Fingerprint matching:

There are many kinds of fingerprint matching algorithms, including point pattern matching, ridge pattern matching, image-based matching and graph-based matching. Minutiae point matching can be viewed as a problem of point pattern matching. Point pattern matching is to match the extracted minutiae set with the minutiae set in the database. If the point sets match through some rotation, scale transformation and translation transformation, then the two fingerprint images are matched.

There are two main ways to realize the fingerprint recognition function of smart locks:

1. Living fingerprint recognition technology

It only produces a recognition response to the living fingerprint of a real person, and does not recognize all other substances, which can effectively distinguish true and false fingerprints. In general, we can do it by using semiconductor fingerprint collectors.

2. Optical fingerprint recognition technology:

The optical recognition of smart locks is an earlier fingerprint recognition technology. Based on the light emitted by the optical emitting device, it hits the finger and is reflected back to the machine to obtain data, and compare it with the database to see if it is consistent.