What is Fingerprint Scanner
In this article, we’ll examine the secrets behind the exciting developments in law enforcement and identity protection. We’ll also look at how Fingerprint Scanners security systems stack up to traditional password and identity card systems and explore how they can fail.
What is Fingerprint Scanner
A fingerprint scanner is a type of electronic security system that uses fingerprints for biometric authentication to provide users with access to information or to approve transactions.
It used to be that fingerprint scanners were mostly seen in movies and TV shows, or read about in science fiction novels. But such a fantasy to surpass the potential of human engineering has been around for a long time – Fingerprint Scanners have been in use for decades! Not only are fingerprint scanners becoming more common in the latest mobile devices, but they are slowly entering everyday life. Here’s what you should know about Fingerprint Scanners and how they work.
Fingerprint Scanner in English
Fingerprints are one of those strange twists of nature. Humans have built-in, easily accessible identity cards. You have a unique design that represents you alone, literally at your fingertips.
People have small ridges of skin on their fingers because it was extremely beneficial to the ancestors of the particularly friendly human species. The pattern of ridges and valleys on the fingers makes it easier to hold things in the hands, just as a rubber pattern helps a tire to grip the road.
Third, fingerprints are a unique marker for an individual, even as identical twins have different fingerprints. And while two prints may look basically the same at a glance, a trained investigator or advanced software can clearly define the difference.
This is the basic idea of fingerprint analysis, both in crime analysis and security. A fingerprint scanner’s job is to replace a human analyst by collecting a print sample and comparing it to other samples on record. In the next few sections, we’ll get to know how scanners work.
Types of Fingerprint Scanners
Fingerprint Scanners work by capturing the pattern of streaks and valleys on a finger. This information is then processed by a pattern analysis/matching software device, which compares it to a list of registered fingerprints on the file. A successful match means that an identity has been verified, to which access can be granted. The method of capturing fingerprint data depends on the type of scanner being used:
1) Optical Sensor in English:
Scanners of this type basically make photocopies of the finger. The heart of an optical scanner is a charge coupled device (CCD), a light sensor system used in digital cameras and camcorders.
A CCD is simply a series of light-sensitive diodes called photosites, which generate an electric signal in response to light photons. Each photosite records a pixel, which is a tiny dot representing the light hitting that spot. Collectively, the light and dark pixels form an image of the scanned scene (a finger, for example).
Typically, an analog-to-digital converter in a scanner system processes the analog electrical signal to produce a digital representation of this image.
The scanning process begins when you place your finger on a glass plate, and a CCD camera takes a picture of it. The scanner has its own light source, usually an array of light-emitting diodes, to illuminate the fingertip.
The CCD system actually produces an inverted image of the finger, with areas of dark color representing more reflected light (finger ridges) and light areas representing less reflected light (valleys between ridges).
Before comparing the printed data, the scanner processor makes sure that the CCD has captured a clear image. It checks for average pixel darkness, or the overall value in a small sample, and rejects the scan if the overall image is too dark or too light.
If the image is rejected, the scanner adjusts the exposure time to let in more or less light, and then tries a scan.
If the processor detects that the image is good and properly exposed, it proceeds to compare the captured fingerprint with the fingerprint on the file.
2) Capacitive Sensor in English:
Like optical scanners, capacitive fingerprint scanners produce an image of the ridges and valleys that make up the fingerprint. But instead of making a print using light, capacitors use electric current.
Instead of light, capacitive scanners use electricity (the way touchscreens work) to determine fingerprint patterns. As the finger rests on the touch-capacitive surface, the device measures the charge; Ridges represent changes in capacitances, while valleys practically do not change at all. The sensor uses all this data to accurately map the prints. Most smartphones with fingerprint scanners use capacitive sensors.
The main advantage of a capacitive scanner is that it requires an actual fingerprint-type shape, rather than the pattern of light and dark that creates the visual impression of a fingerprint. This makes the system more difficult. Additionally, since they use a semiconductor chip instead of a CCD unit, capacitive scanners are more compact than optical devices.
3) Ultrasonic Sensor in English:
How bats and dolphins use echolocation to find and identify objects, dolphins work through echolocation sound waves. The hardware is designed to send out the ultrasonic pulse and measure how much bounce back occurs.
Bulge and gap reflect sound differently, which is what ultrasonic scanners are capable of producing a detailed 3D map of fingerprint patterns. Ultrasonic sensors are currently being prototyped (such as by Qualcomm Technologies, Inc.) and tested for use in mobile devices.
How Fingerprint Scanners Works
Unlike ordinary digital photos, scans have to capture the right amount of detail brightness and contrast – so that individual streaks and other details in the fingerprint can be accurately matched to the scans already taken.
Remember that fingerprints can be used as evidence in criminal trials, where a conviction can result in a long prison sentence or even the death penalty. Therefore “quality control” is an important part of the fingerprint scanning process.
A row of LEDs scans bright light onto the glass (or plastic) surface your finger is pressed against (sometimes called a platen).
Image quality will vary depending on how you’re pressing, how clean or smooth your fingers are, how clean the scanning surface is, the level of light in the room, and more.
Reflected light bounces back from your finger, through the glass, onto a CCD or CMOS image sensor.
The longer this image-capture process, the brighter the image formed on the image sensor.
If the image is too bright, areas of the fingerprint (including important details) can be completely washed out – such as an indoor digital photo where the flash is too close or too bright. If it’s too dark, the whole image will look black and the details will be invisible for the opposite reason.
a Algorithm Tests whether the image is too light or too dark; If so, a sound beep or LED signal alerts the operator and we go back to step 1 to try again.
You might be staring at your fingers right now, wondering how or whether scanners can determine a match so quickly. Decades of work have led to the classification of fingerprint nuances – the elements that make our fingerprints unique. Although there are over a hundred different features that come in handy, fingerprint analysis basically looks to plot the points where ridges suddenly end and fork in two branches (and direction).
Combine that information with the orientation of the common fingerprint pattern — arches, loops, and whorls — and you’ll have a pretty reliable way of identifying individuals.
Fingerprint scanners include all these data points in the template, which is used when biometric authentication is required. More data printed helps ensure greater accuracy (and speed) when comparing different sets of prints.
The scanner system software uses highly complex algorithms to detect and analyze these details. The basic idea is to measure the relative position of the star, the way you can identify a part of the sky by the relative position of the stars. A simple way to think about it is to consider the shapes when you draw straight lines between them. If two prints having three rigid endings and two divisions form the same shape with the same dimensions, find the probability that they are the same print.
In order to find a match, the scanner system does not need to find the entire pattern of nuances both in the sample and in the print on the record, it just needs to find a sufficient number of fine-grained patterns that are the same across the two prints. The exact number varies according to the scanner programming.
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