Introduction to Access Control Technology
With the continuous development and breakthroughs of biometric technology in recent years, its application in access control systems has become increasingly mature and widely used in scenarios such as banks, hotels, parking lot management, computer rooms, armories, residential areas, confidential rooms, factories, etc.
There are many new technologies such as biometric access control systems, mainly based on human biometric features as recognition conditions. Currently, China's biometric access control systems are divided into facial recognition, fingerprint recognition, iris recognition, palm print recognition, finger vein recognition, voiceprint recognition, etc.
Let's take a look at the widely used facial recognition access control system, fingerprint recognition access control system, iris recognition access control system, palm print recognition access control system, and QR code access control system in China:
1. Facial recognition access control system
Compared to other recognition technologies, facial recognition technology has advantages in the application process, such as being more convenient in image information collection and gradually becoming the most direct and natural biometric recognition technology. It has become the focus of current artificial intelligence and pattern recognition, and has also been widely used in access control systems.
The facial recognition access control system collects facial information of all personnel allowed to access the access control system and stores it in a facial database. When a person accesses the access control system, the facial recognition access control system will first obtain portrait information through the camera, and then input the collected portrait information into the computer for facial recognition. This process system preprocesses the visitor's portrait information to avoid the influence of facial expressions, lighting, and input devices on the results. The preprocessed portrait is subjected to feature extraction, and the extracted information is recognized and compared with the facial information in the database, and the recognition results are recorded. Once facial information that can be successfully compared is identified in the database, the access control system will receive the computer's door opening command and allow visitors to enter through the hardware part of the access control system; Otherwise, the computer will not issue the command to open the door, the access control system will not open, and the visitor's facial information will be recorded for future reference and supervision.
Due to the ability of facial recognition access control systems to recognize and record faces remotely, quickly, and contactless, in buildings and communities where conditions permit, the access control system can be connected to blacklist databases or public security databases and compared in real time to detect suspicious individuals in a timely manner and automatically issue warnings, achieving intelligent security management.
2. Palmprint recognition access control system
Palm prints contain rich information, and by utilizing the line features, point features, texture features, and geometric features of palm prints, one can determine a person's identity. The foundation of palmprint recognition technology is palm geometry recognition. Palm geometry recognition is achieved by measuring the physical characteristics of the user's palm and fingers, and advanced products can also recognize three-dimensional images.
Palm geometry recognition is relatively convenient to use. It is suitable for scenarios with a large number of users or easy acceptance, with very high accuracy. Within less than 1 second, the user's identity is confirmed by detecting three-dimensional features such as the size, shape, and surface area of their palm to ensure that only authorized personnel can enter specific areas, thus achieving the purpose of access control. As an alternative to RF card access control systems, palmprint access control systems save users the cost of using and managing cards, and can also be combined with other access control systems to increase security. Compared with fingerprint recognition systems, palm recognition systems have features such as dirt and scars that do not affect measurement, easy alignment of hands and placement in the correct position of the scanner, making it easy for users to accept.
3. Iris recognition access control system
The iris recognition access control system determines people's identity and decides whether to unlock the door by comparing the similarity between iris image features. The process of iris recognition technology generally includes four steps: firstly, using specific camera equipment to capture images of the human eye, obtaining iris images, and transmitting them to the image preprocessing software of the iris recognition system. Secondly, locate the iris and determine the positions of the inner circle, outer circle, and quadratic curve in the image; Adjust the iris size in the image to the system settings parameters and perform image enhancement together. The third is to use specific algorithms to extract feature points required for iris recognition from iris images and encode them. The fourth step is to match the feature codes obtained from feature extraction with the iris image feature codes in the database one by one, to determine whether they are the same iris, thus achieving the purpose of identity recognition. Iris recognition access control system does not require physical contact, with low misidentification rate and high reliability; But it is difficult to miniaturize front-end devices, the cost is high, and it is difficult to promote on a large scale.
4. QR code access control system
The QR code access control system is an access control system controlled and managed by mobile QR codes, integrating WeChat, cloud services, QR code recognition, and entrance and exit management. Users can send control commands to the access control system through their mobile phones, enabling QR code opening, remote control of door opening, authorization management, sending invitation codes to specific personnel, checking door opening and closing records, and querying system logs. Users can implement specific operations through WeChat official account or WeChat applet. After successful registration by ordinary users and approval by the administrator, they can use the access permissions represented by the generated QR code. Advanced users or administrators can review new user applications and choose to reject or approve them. Users can either scan the QR code at the entrance and exit through WeChat to unlock the door, or fill in the information of the invitee, set the validity time of the QR code, and send the generated QR code to the invitee through WeChat. Scan this QR code through the camera on the access control within the valid time to open the corresponding door lock and allow passage.
The two-dimension code access control system is characterized by that it can directly build servers and databases in the cloud, and customize the service platform to connect to the WeChat official account interface or applet; Adopting a dynamically variable QR code method, each user is assigned an encrypted QR code in real time, and the refresh time of the QR code can be set. If the QR code is not scanned, it will be immediately refreshed to prevent intentional copying and theft; By linking to cloud servers through WeChat or web pages, administrators or advanced users can remotely open doors through their mobile phones; Foreign visitors can obtain access to the entrance in advance; Administrators can directly log in to the backend management system through the webpage to carry out management, and can achieve functions such as project authorization, user review, and event inquiry. They can view and manage visitors' applications and entry and exit records anytime and anywhere; It is relatively easy to use. Considering the real name registration system for mobile phones and the binding of mobile payments and bank accounts. There is unlikely to be a possibility of borrowing a mobile phone, and it is basically possible to confirm the binding to ensure the safety of personnel.
5. Fingerprint recognition access control system
The hardware of the fingerprint access control system mainly consists of microprocessors, fingerprint recognition modules, LCD display modules, keyboards, clock/calendar chips, electronic locks, and power supplies. The microprocessor serves as the upper computer of the system, controlling the entire system. The fingerprint recognition module mainly completes functions such as collecting, comparing, storing, and deleting fingerprint features. The LCD display module is used to display information such as door opening records, real-time clock, and operation prompts, and is combined with the keyboard to form the human-machine interface.
The fingerprint reading device (collector) uses photoelectric technology or capacitive technology to collect fingerprint information, then extracts features and compares them with stored feature information to complete the recognition process. This process is entirely completed in the reading device, or the reading device can only perform fingerprint collection and then transmit it to the backend device (such as PC) for feature extraction and recognition. The device for individual fingerprint collection is easy to miniaturize, convenient to use, and has a fast system recognition speed. The requirement for fingerprint feature collection is to establish a specified relationship between the human fingers and the collector during operation So the system is slightly less user-friendly.
Biostatistics shows that fingerprints have a high degree of similarity, and the probability of the same fingerprint appearing between people is very low, so the security is high, but there is still a risk of being copied. So, products with live fingerprint collection capabilities have emerged, mainly by increasing the detection of temperature, elasticity, and microvessels to confirm the authenticity of the collected fingerprints. In addition to fingerprint recognition, other identification methods such as passwords should also be added to enhance the security of the access control system with security requirements.