background

　　

The video surveillance system is mainly used to better observe the actual situation in the community, protect the assets of the community from loss, prevent theft by outsiders, protect personal safety, and implement automated security management for the community. The video surveillance system is the most important part of the entire residential community security system. Set up cameras at the perimeter, entrances and exits of the community, main roads, etc. for video tracking, automatic recording, and post event review. Establish a comprehensive and powerful technical defense system using technical defense measures to meet customers' security requirements. At the same time, cooperate with personnel management to achieve unity and coordination between civil defense and technical defense, in order to achieve the goal of safe and efficient management.

　　

The design of the video surveillance system for this construction is based on a high-definition network system architecture, applying multimedia control and management technology based on computer networks. The control, storage, transmission, and query of surveillance video images are integrated into the unified management of the computer network, jointly building a practical, efficient, and fast security monitoring system. Provide advanced technological means for security monitoring systems to ensure the safety of the entire area. At the same time, combined with the trend of informationization, networking, and digitalization in today's society, a complete comprehensive video surveillance system based on internal LAN is proposed to be established within its regulatory scope.

　　

The design of this video surveillance system is a fully digital high-definition network monitoring system based on TCP/IP transmission. The signal line uses CAT6UTP and is reserved in the comprehensive cabling. Digital network video signal display, using an 8-channel network video decoder to display the video signal on the TV wall. The network digital video storage device uses NVR storage, and the recording time is saved for 30 days.

　　

　　System Architecture　　

　　

Design Notes:

　　

The entire video surveillance system adopts a network digital architecture form;

　　

The front-end camera adopts corresponding high-definition network gun cameras and high-definition network spherical cameras according to different environmental locations;

　　

The front-end network camera collects signals, encodes and compresses them into digital IP signals, and transmits them to the monitoring center NVR for storage through the network, which is then directed by the streaming media server to the disk array for storage;

　　

◆ The center is equipped with high-definition decoders, streaming media servers, network video recorders (NVRs) and other devices for global management, multi-user access, and storage requirements;

　　

The high-definition decoder configured in the center can decode up to 8 1080P network videos simultaneously, and supports three different interfaces: DVI, VGA, and HDMI for output. The output image has a segmentation method, which can be configured with 1 or 4 image segmentation methods;

　　

Network switches are equipped with 100Mbps and 1G switches according to actual needs to achieve redundant transmission and switching of network data.

　　

　　System Composition

　　

This system mainly consists of front-end cameras, transmission links, and central control/display parts. The cameras at each monitoring point send video image signals to the monitoring center through the network, and store them through devices such as network video recorders (NVRs). Computers can query monitoring video recording and other data through the client; On the other hand, multiple monitoring images are displayed in real-time in front of the on duty personnel through the display unit set up in the control center.

　　

1. Front end video capture system

　　

The front-end video capture system is designed to observe and collect information. The front-end monitoring equipment can adopt high-definition network cameras based on the standard H.264 algorithm according to the actual needs of users. The compressed resolution of high-definition network cameras reaches 1280 * 720. Due to the standard 16:9 widescreen display ratio of high-definition network cameras, they have a larger visual range than traditional analog videos. Moreover, due to their higher effective pixels and resolution, the resulting video images are clearer than traditional analog cameras.

　　

2. Video transmission system

　　

The transmission private network for videos is to ensure smooth video flow, similar to the "blood vessels" of the human body, which need to be ensured not to be blocked. The main equipment includes access switches, fiber optic transceivers, aggregation switches, core switches, backbone transmission optical cables, and video access using Category 5e (Category 6) unshielded twisted pair cables. The construction of a dedicated video transmission network needs to consider bandwidth, packet forwarding rate, backplane bandwidth, multicast, and QoS technologies. If the video transmission network requires external network access, security and antivirus measures need to be taken, and a firewall needs to be added in the private network system.

　　

In terms of the relative relationship between video quality and access bandwidth for monitoring, an upstream bandwidth of 384Kbps can transmit clear and smooth CIF resolution images, an upstream bandwidth of 512Kbps can transmit clear and smooth 2CIF resolution images, and an upstream bandwidth of 1.5Mbps can transmit clear and smooth D1 resolution images. The video bandwidth for high-definition 720P transmission is approximately 2.5Mbps-6.6Mbps. Select different switches for exchange and transmission based on the actual number and bandwidth of cameras.

　　

3. Central management control system

　　

The monitoring center is the core of the entire system, connecting various monitoring resources and managing, storing, calling, and displaying them accordingly. Its main purpose is to improve security prevention and provide a centralized application venue for decision-making, command and dispatch, and evidence collection by leaders at all levels. The central control design of this system consists of three parts:

　　

1) Control section

　　

The control part of this system consists of NVR and high-definition decoder stations, mainly responsible for media scheduling and video forwarding, central storage and network management, and other application interface services. A high-definition decoder is a specialized device used for video control switching to the wall, controlling image processing functions such as video display and stitching.

　　

2) Network storage section

　　

The storage of videos plays an important role in ensuring the retrieval of historical alarm events and facilitating post event evidence collection. So the resolution of the image is crucial, and the backend video storage devices mainly include network hard disk recorders and video dedicated hard disks. The stability of the device determines the overall performance of the system, so the storage requirements for backend videos are based on the UNIX operating system. The image resolution must reach 720P (1280 * 720) or higher to ensure the clarity of video playback details. This design features a centralized storage system consisting of disk arrays.

　　

◆ Video capacity storage calculation

　　

Calculated based on single channel 720P image quality, 4M/S bitrate, and 30 day video storage:

　　

Single channel capacity=3600 seconds x 24 hours x 30 days x 1 channel x 4M ÷ 1024 ÷ 1024 ÷ 8=1.24T

　　

151 channel capacity=1.24T × 151 (channels)=187.24, with an additional redundancy of 15%;

　　

Total capacity=216T

　　

3) Display section

　　

The image display unit consists of 20 26 inch monitors and 1 60 inch monitor.

　　

　System functions

　　

1. Monitor/Large Screen Display

　　

◆ Real time display of high-quality images;

　　

◆ Support multi-channel combination switching and rotation screen display mode;

　　

Utilize cameras installed at various points to monitor the environment in real-time within all monitoring areas;

　　

◆ It can display images of different sizes according to changes in camera focal length (zoom camera), and can display monitoring images from various directions according to changes in angle (ball camera).

　　

The brightness, chromaticity, contrast, and grayscale of the image can be adjusted;

　　

2. Screen switching

　　

Users can switch the monitoring screen arbitrarily. They can switch the video from any camera to the monitor screen, or switch the video from one camera to any monitor display.

　　

3. Group switching

　　

Group switching refers to simultaneously switching multiple video inputs to multiple consecutive outputs. Multiple independent groups (group switching), each consisting of multiple video outputs (each with a target and an auxiliary touchpoint action), can be called manually or as part of a general patrol.

　　

4. Screen rotation

　　

Patrol is a sequence of multiple camera positions. Operators can define outputs for patrols at any time. Each camera position includes an associated preset scene, image, and/or auxiliary touch point action. The same video input can be inserted into multiple locations of the same patrol. Inspection can run in either forward or reverse direction. The video input that has been cut off by the monitor will not be displayed.

　　

5. Pan tilt control rotation

　　

Users can control the up, down, left, and right rotation of the ball machine to obtain monitoring images from different directions, providing better monitoring of the equipment scene.

　　

6. Preset position function

　　

Users can set preset positions for ball machines or gimbals with preset positions. Users can set preset positions for points that require special observation (the number of preset positions is determined by the selected integrated ball machine and gimbals), and multiple preset positions can be set (determined by specific matrix models). Users can input the command to call the preset position to view the preset position screen that needs to be monitored. Users can also incorporate preset positions into the inspection screen and display them on the monitor.

　　

7. Video playback

　　

Provide convenient video retrieval and query methods, which can retrieve and replay images based on information such as time, location, and alarm type.

　　

The playback user interface is user-friendly, allowing users to intuitively reflect the status of the recorded data for the date being checked, and can also click to play. When users choose to watch a video that is currently being recorded, they can choose to package and play it for the user, which can achieve the function of downloading videos by file and time segment.

　　

7. System features

　　

① The front-end is equipped with a high-definition network camera with a maximum resolution of 1280 * 720P, 25 frames per second in real-time, clear and natural images, short network latency, and the ability to monitor from a large angle and over a wide range;

　　

② The high-definition decoder can flexibly call and control data, and can achieve the operation functions of display, splicing, and other large screens;

　　

③ The system adopts modular design, with flexible structure and strong scalability. Both front-end and central expansion can fully utilize early resources and reduce expansion investment costs;

　　

④ The system management platform implements hierarchical control over the same monitoring point or group of monitoring points according to different permissions and levels. Has multi-level, multi permission, and multi password control. Among them, the local is Z advanced, with all operational permissions based on the password. The usage permissions of other users are uniformly set and managed by the command center, and strict login and user permission management systems are implemented on the digital platform.

　　

⑤ The core hardware devices and management software of the system are independently developed, which can provide timely and good after-sales service, respond to users' special needs, and tailor functions according to users' requirements.