Nowadays it is common to find access control devices as well as time and attendance control equipment in almost any office. These devices are used to restrict the passage of people to certain sections or areas of the facilities and to control the working hours of the staff, respectively.

biometric multitechnology

A few years ago, staff identification at these terminals was carried out by means of radio frequency cards (RFID cards) or numerical passwords. However, these methods were easily circumvented due to the simplicity of transferring such credentials to another person or easily duplicating them. For this reason, biometric identification was developed, as it ensured the creation of unique and non-transferable credentials. In addition, this type of credential does not require a physical support as such, which has made it the ideal tool for use in portable electronic devices such as cell phones or tablets, or for use in work environments where, due to hygiene reasons, no element that can transmit bacteria, viruses or germs can be used.

In this aspect, ZKTeco, the world's leading manufacturer of access control and time and attendance control systems, is at the forefront of the market, betting on cutting-edge, top-quality technology. Visiotech is working closely with ZKTeco to offer the best products and the best service.

Biometric identification methods are divided into two main groups:

Contact recognition

In these systems it is necessary for a part of the person's body to come into contact with the biometric recognition terminal in order to validate the credential. They are the most common systems, and the ones that were first developed.

Within this group we find fingerprint recognition. fingerprint recognition. This system registers the fingerprint pattern of the fingers of people's hands. To identify oneself using this method, it is necessary to place one's finger on the surface that acts as a reader. In this system it is common to find two types of sensors:

  • Optical sensors: in this type of sensor the finger is placed on a transparent surface, usually made of glass or methacrylate, which is illuminated by an LED diode. The light emitted by this component is reflected on the different ridges of the finger, being registered by an image sensor, together with the dark zones generated between these ridges. Although theoretically this system works very simply, in practice it has some disadvantages, such as the alteration of the fingerprint image if the finger is wet, as well as being quite sensitive to dust, dirt or sunlight. These factors cause the reflection of the light from the LED to be altered. In addition, if the person's fingerprint is in poor condition, identification may not be possible.
  • optical sensors fingerprint
  • Capacitive sensors: In this type of sensor, the finger is placed on a silicon integrated circuit, the surface of which is made up of a large number of transducer elements, also called pixels. The typical resolution is around 500 dpi. In this case, the fingerprint image is generated by varying the capacitance of metal electrodes adjacent to the transducer elements: the capacitance is reduced more when detecting ridges, and less when detecting gaps between them. Due to this performance, this type of sensor is suitable for outdoor operation, unlike the previous ones. However, this system also has some limitations, such as working with zones with calluses or scars, as well as due to the presence of moisture, grease or dust.
  • Although it is true that the combination of these two systems covers most of the identification needs through fingerprinting, there may be environments with more restrictive conditions,, such as mechanical workshops or assembly lines, where it is common for workers to have grease on their hands or damaged fingerprints due to the development of their professional activity. For these situations, ZKTeco has developed a powerful optical sensor, known as Z-ID,, which can handle fingerprints in these conditions. In addition, it is also able to work in outdoor environments, even though it is an optical sensor.

    optical sensor Z-ID

Contactless recognition

In these systems it is not necessary for a part of the person's body to come into contact with the biometric recognition terminal in order to validate the credential. They are more advanced than the previous ones and stand out for their greater reliability and ease of use, in addition to improved hygiene during the identification process.

This group includes facial recognition and palm recognition systems.

Facial recognition systems:

with facial recognition, the pattern of a person's face is registered. To identify oneself using this method, it is necessary to place the face in front of the camera of the device that performs the verification.

Although fingerprint identification is valid in all types of environments thanks to the different sensors that can use this technique, it is true that there are jobs where it is necessary for safety reasons to wear gloves or other protective elements for the hands, so it is impossible to place the fingerprint naked in the readers. Because of this, facial recognition is presented as the immediate biometric alternative to the fingerprint.

The first devices using this type of biometrics had a single camera for verification. However, while the identification was effective, it was also easily fooled by being able to use a photo or video of the person in question to impersonate his or her identity. This was because, in the absence of dual cameras, it was not possible to verify depth and therefore could not differentiate a real image from a photograph or video. Thanks to the implementation of the dual camera in facial recognition, this security vulnerability could be overcome by implementing anti-spoofing technology in these devices.

facial recognition systems anti-spoofing technology

Facial recognition also has some limitations when it comes to verification, such as the need to immobilize the face in front of the camera or to present the face in front of the camera. In this regard, manufacturers such as ZKTeco have developed a powerful and innovative technology, called Visible Light, to overcome these limitations. Thanks to this technology, the identification of people's faces can be performed proactively, i.e. without stopping in front of the camera, as well as showing the face at an angle, both horizontally and vertically. All this is possible thanks to the Deep Learning algorithm it uses.

As was the case with hands, in certain environments it is also necessary to protect the respiratory tract by using masks, such as in laboratories or medical centers. Facial recognition technology has evolved to the point where people can be identified only through the upper half of the face. This has made it possible to combine the use of face masks with facial recognition.

Hand palm recognition systems:

This system records the pattern of a person's palm. As with facial recognition, palm recognition works by placing the front of the hand in front of the camera of the device that performs the verification.

For this biometric method it is not necessary to use any additional or special camera compared to those used for facial recognition, only to have a double camera to check the depth of the image.

Although biometrics has clear advantages over traditional identification methods, this system is not completely infallible. This is not due to the quality of the different modes of verification, but to the different constitution of individuals. In some cases, facial features or the arrangement of fingerprints may exceed common standards, and the device may not be able to identify them. However, this is not a problem, since all biometric devices have several identification systems, either different biometric methods or biometric methods and conventional methods. This ensures that in any device with biometrics, no person will ever be unidentifiable.

In conclusion, the equipment for access control and time&attendance control with biometric identification are the best choice to cover any need for verification of people in any facility, due to its convenient and fast technology and the ease of transport and security of their credentials.  

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