Fingerprint Scanners: How Do They Work

By Author: Mujib Khan
Total Articles: 1
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Advances in technology bring helpful changes to improve our lives, and fingerprint scanners are certainly part of that. We are talking about an effective "identification system", which is gradually becoming an indispensable element in electronic devices. For example, many smartphones are equipped with a helpful fingerprint scanner to "enable" the whole operation for the rightful owner. The same fingerprint scanners can be used to open a door, a gate to authorized persons.
Today's laptops come pre-installed with a fingerprint scanner. In addition, Asperating systems and websites begin to support biometric fingerprint scans; however, if you're using older hardware, don't think about throwing it out just yet; however, add this functionality by grabbing a USB reader.
In short, fingerprints are different, everyone has their own, and they change from individual to individual. No two are alike, even if they are similar. It is on this idea that the operation of the fingerprint scanners is based. Any other person's fingertip will never open a door, perhaps alarmed. Instead of electronic keys, remote controls, numerical codes, ...
... we can control burglar alarms and alarm systems using our finger.
How a fingerprint scanner works
The fingerprint scanner, or "Fingerprint reader" or "Fingerprint sensor", is a biometric identification device whose primary function is to recognize finger pads through light or electrical sensors, memorize them and uniquely identify people.
Its validity, as mentioned, is mainly based on the fact that finding two identical fingerprints is practically impossible. In addition, fingerprints have a genetic component, influenced by factors such as the fetus's position in the womb or the density of the amniotic fluid, so twins also have entirely different fingerprints.
When the readers detect the fingerprint, they can create a digital image for storage in a database and associate the fingerprint with a person or name. An algorithm extracts specific points of the fingerprint image, transforms it into an encrypted code that represents each person and is stored in a database.
So every time someone puts their finger on a fingerprint scanner, the photocell automatically scans the specified points and compares them with the stored database, accepting or refusing access.
Today, a growing number of companies or individuals who choose fingerprint detectors as their method of access are many—the endless applications. There are USB fingerprint scanners that plug into PC ports to grant access. There are sensors connected to alarm control units or electric motors that open the doors or control units that deactivate alarms.
At the moment, this system is considered one of the best biometric identification tools that offer a high degree of security, reliability and speed to identify and authorize people.
Optical fingerprint scanner:
The most common type of fingerprint scanner works with the same logic as a digital camera. Simplifying, take a picture of your finger and send it for processing. The general idea is as follows:
1. The scanner illuminates the finger with the help of an LED and takes a picture.
2. If the average image pixel value of the photo is too dark or too light, adjust the exposure and try again.
3. It checks the resolution quality by checking if dark and light areas alternate consistently with clearly defined ridges and valleys.
4. If the image is adequate, it can be processed.
This type of scanner is more common in places like police stations, airports and secure entrances but is not often used in smartphones favouring smaller, safer capacitive sensors. One exception is smartphones with "in-display" scanners, some of which use optical or ultrasonic sensors under the screen to get the image. Even in this case, however, optical sensors tend to lose ground in favour of ultrasound fingerprint scanners which are slower but have the advantage of not being able to be deceived by two-dimensional images of your fingerprints.
Capacitive fingerprint scanner:
When we put our finger on a capacitive scanner, small amounts of electricity are used to measure the distance between the different parts of the fingerprint and the scanner. Inside the scanner are rows of small capacitors, each of which contains an electrical charge. If one of the capacitors is located below one of the ridges of the impression, it can be charged more as it comes into contact with the skin. If, on the other hand, it is located under a valley, the condenser will remain in touch with the air, which will not allow it to store additional charge.
You can somehow think of these capacitors as the pixels in a camera. If one contains more charge, it can be interpreted as a ridge area, while the others are read as valleys. It would need the set of all the measures taken together to give an image of the fingerprint just as accurate as of that of an optical sensor, but even more secure since a three-dimensional model of the fingerprint to deceive it rather than just a two-dimensional model. This, combined with its smaller size, makes capacitive scanners a prevalent choice among smartphone makers.
Ultrasonic fingerprint scanner:
We can say that this type of reader is the most advanced and current. It is mainly based on an ultrasonic emitter and receiver, which will establish a three-dimensional image of the fingerprint. Therefore, this reader allows you to get more information than traditional readers.
Fingerprint analysis
After the image has been captured using light, electricity or sound, the software must check whether the fingerprint corresponds to an authorized user. To understand if the fingerprints correspond, the "minutiae" are mainly evaluated, that is - simplifying - the terminations or bifurcations of the crests.
Each of these characteristics is then assigned a position concerning the other minutiae detected and the distance and angle between each element. The scanner software can create a sort of map that a sequence of numbers can represent. This sequence represents the coded fingerprint.
All of the fingerprint data our devices store, even if it's just the minutiae maps, are generally protected in a secure environment, isolated from other applications that may try to access that information. Furthermore, all applications or websites accessed using the fingerprint will never receive the fingerprint data. Only the confirmation from our device that the fingerprint has been scanned matches one of those in memory.

Advantages of using a fingerprint scanner
Among the countless advantages of a fingerprint scanner, we have:
1.They allow perfect identification since a person's fingerprints cannot be falsified.
2.Avoid manually typing codes or passwords.
3.No expensive and difficult-to-understand software is required for it to function.
4.If you use it as a login to a business, you will save on expenses since you don't need to invest in electronic badges.
5.It will no longer be possible to forget codes, passwords or keys.
6.It does not require additional devices.
7.Low cost in terms of maintenance, compared to other systems, the fingerprint scanner has a lower maintenance cost than others.
8.Less attempt at sabotage. As we've already mentioned, tracing a fingerprint is nearly impossible, but a password or pin code can be copied.
Fingerprint scanners are not the most foolproof way to control access to a confidential resource as they can be fooled by good 2D or 3D reproductions of our fingerprints. Still, they improve accuracy and speed, while Security protocols for storing and managing fingerprint data are already robust enough (as long as they are used).

I'm working as a technician. I like to gather knowledge about new technology. And also inform others.