Video Surveillance System

Image Acquisition

The camera, as the front - end device of video surveillance, has an image sensor at its core. CMOS (Complementary Metal - Oxide - Semiconductor) image sensors have become the mainstream choice due to their advantages such as high resolution, low power consumption, and high cost - effectiveness. It can efficiently convert optical signals into electrical signals, providing the original data for subsequent image processing. For example, in urban road monitoring, high - resolution CMOS image sensors can clearly capture the details of vehicles and pedestrians, facilitating accident tracing and public security management. The lens determines the shooting angle and imaging quality of the camera. Optical lenses, focusing motors, and other components work together to achieve precise focusing and clear imaging in different scenarios. In addition, infrared LED lights are used for night - vision functions. In low - light or no - light environments, they emit invisible infrared light to the human eye, enabling the camera to obtain clear images and ensuring round - the - clock monitoring.

Video Processing and Transmission

The IPC SoC (IP Camera System on Chip) chip is the core of the video - surveillance network camera. It is responsible for processing and encoding the original video data collected by the front - end image sensor of the camera, ensuring the efficient transmission of video data over the network. In complex security - monitoring scenarios, such as large shopping malls and enterprise parks, where multiple video streams are transmitted simultaneously, the IPC SoC chip compresses and encodes the video through advanced algorithms, reducing the data volume and the pressure on network bandwidth. The video encoder converts analog video signals into digital signals and compresses them for convenient network transmission and storage. At the same time, to ensure the stability of video transmission, electronic components such as signal amplifiers and network transformers are used to enhance the signal strength, isolate, and match the network interface, ensuring that the video data is accurately transmitted to the back - end storage and display devices.

Storage and Display

The NVR (Network Video Recorder) SoC chip, as the core of the network video recorder, is responsible for receiving the digital video code stream transmitted by the network camera, and performing decoding, storage, management, and playback. In large public places, such as airports and railway stations, a large amount of surveillance video data needs to be stored for a long time. The efficient storage management function of the NVR SoC chip can ensure the reliability of data storage and fast retrieval. The storage device itself, such as a hard disk drive (HDD) or solid - state drive (SSD), is used to actually store video data. In the display link, the display screen and related driver chips present the decoded video images for security personnel to view in real - time. For example, the large - screen splicing display system in the monitoring center combines multiple display screens to achieve panoramic and high - definition video display, facilitating real - time monitoring and management of large - area regions.

Intrusion Alarm System

Sensor Detection

The intrusion alarm system relies on various sensors to sense abnormal situations. Infrared detectors utilize the infrared - radiation characteristics of the human body. When a person enters the detection area, the infrared radiation of the human body differs from that of the environment. After the detector detects this change, it triggers an alarm signal. Door - magnetic sensors are installed on doors and windows. By detecting the opening and closing state of doors and windows, once the doors and windows are illegally opened, an alarm signal is immediately sent. Vibration sensors are used to monitor the vibration of objects, such as safes and fences. When abnormal vibration occurs, the sensor converts the vibration signal into an electrical signal and transmits it to the alarm host. These sensors usually adopt MEMS (Micro - Electro - Mechanical Systems) technology and integrate electronic components such as sensitive elements and signal - conditioning circuits. They have the characteristics of high sensitivity, low power consumption, and miniaturization, and can accurately and timely detect intrusion behaviors.

Alarm Host Processing

The alarm host is the core control unit of the intrusion alarm system. It receives signals from various sensors and analyzes and processes them. The microprocessor inside the host judges whether an intrusion event has occurred according to the preset alarm rules. If an intrusion is confirmed, the host sends alarm information to relevant personnel through communication modules, such as GSM (Global System for Mobile Communications) modules and Ethernet modules, such as sending text messages to property security personnel and pushing messages to the monitoring - center software. At the same time, the alarm host can also control devices such as audible and visual alarms to emit loud alarm sounds and flashing lights, deterring intruders and attracting the attention of surrounding people. The alarm host also integrates a power - management module to ensure that the backup battery can continuously power the system when the mains power fails, ensuring the uninterrupted operation of the system.

Transmission and Linkage

The transmission of alarm signals requires reliable communication lines and the support of electronic components. In wired transmission methods, twisted - pair wires and coaxial cables are used to connect sensors and alarm hosts. During the signal - transmission process, components such as signal amplifiers and isolators are required to ensure the stability and accuracy of the signal. Wireless transmission relies on wireless communication technologies such as WiFi, Bluetooth, and ZigBee. The relevant wireless modules and antennas are responsible for signal transmission and reception. In addition, the intrusion alarm system can also be linked with other security systems. For example, it can be linked with the video - surveillance system. When an alarm event occurs, it automatically triggers the cameras in the relevant area to record and capture images, providing evidence for subsequent investigations. In intelligent buildings, the alarm system can also be linked with the access - control system. When an intrusion is detected, the entrances and exits of the relevant area are immediately blocked to prevent intruders from fleeing.

Access Control System

Identity Recognition

The card reader is a key device for identity recognition in the access - control system. The RF - card reader communicates with the RF card carried by the user through radio - frequency identification technology and reads the identity information stored in the card. Its working principle is based on electromagnetic induction. The card reader emits a specific - frequency radio - frequency signal. The coil in the RF card generates an electric current when it senses the signal, driving the chip in the card to work, and modulating and feedbacking the stored information to the card reader. Biometric technologies are also increasingly used in access - control systems. The fingerprint - recognition module collects and compares the fingerprint feature points of users, and the face - recognition camera analyzes face features using image - recognition algorithms to achieve high - precision identity verification. These identification devices integrate sensors, signal processors, and other electronic components, which can quickly and accurately identify user identities, ensuring that only authorized personnel can enter the corresponding area.

Control Execution

The access - control controller judges whether the user has access rights according to the identity information transmitted by the card reader or biometric device. If the user has the right, the controller controls the actions of electromagnetic locks or electric - bolt locks and other actuators through relays to open the access control. The relay, as an electrical control device, realizes the closing and opening of contacts through electromagnetic force, thereby controlling the on - off of the door - lock power supply. For example, in the access - control system of an office building, after an employee swipes a card or has their face scanned for identity verification, the access - control controller controls the relay to act, and the electromagnetic lock is powered off and released, allowing the employee to open the door and enter. To ensure the security of the access - control system, a backup power supply, such as an uninterruptible power supply (UPS), is also equipped. When the mains power fails, it ensures that the access - control system can still operate normally and prevents the access control from getting out of control due to a power outage.

System Management

The access - control management software is the management core of the entire access - control system and runs on a computer or server. The software communicates with the access - control controller through the network interface to achieve centralized management of the access - control system. It can input, modify, and delete user information, set the rights of different users, such as the areas and time periods allowed to enter. At the same time, the software can also record and query all access - control operation records, including information such as the time and location of personnel entry and exit, facilitating security audits and management traceability. Network devices such as network switches and routers are used to build the communication network of the access - control system, ensuring the fast and stable transmission of data between the access - control controller, management software, and other related devices. In large enterprises or parks, there may be multiple access - control controllers. Through network devices, they are connected into a unified access - control management network to achieve efficient and convenient management.

Intelligent Security System

Artificial Intelligence Chips

With the in - depth application of artificial intelligence technology in the security field, artificial intelligence chips have become the core driving force of intelligent security systems. These chips are specially designed to run complex artificial intelligence algorithms, realizing intelligent analysis of video images, behavior recognition, and anomaly detection. For example, deep - learning chips can quickly process and analyze the massive data in surveillance videos, identify the behavior patterns of people, such as loitering, running, fighting, and other abnormal behaviors, and issue alarms in a timely manner. In urban security, artificial intelligence chips are used to monitor and analyze traffic flow in real - time, enabling intelligent traffic management, optimizing traffic - signal timing, and improving road - traffic efficiency. At the same time, in video surveillance, artificial intelligence chips can also be used for applications such as license - plate recognition and face recognition, improving the intelligence level and accuracy of security systems.

Edge Computing Devices

Edge computing devices play an important role in intelligent security systems. They are close to the data - collection end and can perform real - time processing and analysis of the collected data locally, reducing data transmission volume and network latency. For example, edge - computing cameras integrate computing chips and storage modules and can directly perform intelligent analysis of video images at the camera end, such as detecting target objects and identifying behaviors. Only when abnormal situations are detected will the relevant data be uploaded to the cloud or back - end server. This not only improves the response speed of the system but also reduces the pressure on network transmission and cloud storage. In some security scenarios with high real - time requirements, such as banks and prisons, edge - computing devices can quickly and accurately process and respond to alarm events, ensuring the safety of the 场所.

Internet of Things Communication Modules

Intelligent security systems achieve interconnection and data sharing among devices through the Internet of Things technology. Internet of Things communication modules, such as NB - IoT (Narrowband Internet of Things) and LoRa (Long Range), are used to connect various security devices to the Internet of Things. These modules have the characteristics of low power consumption and wide coverage, which are suitable for the communication needs of a large number of security sensors and devices distributed in different locations. For example, in smart - home security, door - and - window sensors, smoke alarms, and other devices are connected to the home gateway through Internet of Things communication modules, and then the data is uploaded to the cloud server through the gateway. Users can view the security status of their homes at any time and anywhere through the mobile APP. In large commercial buildings or parks, through Internet of Things communication technology, access - control systems, video - surveillance systems, alarm systems, and other subsystems can be integrated together to achieve unified management and intelligent linkage, improving the overall efficiency of the security system.