Basic monitoring training (1)

system design:

1. 2 small and medium TV monitoring system

The usual TV monitoring system is not large in scale and its functions are relatively simple, but its scope of application is very wide. The monitored objects are not limited to the people, commodities, goods or vehicles that are thought of. Some application systems also involve monitoring such as natural gas tanks and high ink melon furnaces, while other application systems need to bend the factory chimney and sewage pipes Monitor. The TV monitoring system can be self-contained or combined with an anti-theft alarm system or an entrance and exit control system to form a comprehensive security monitoring system. Generally speaking, the camera monitoring points of a typical small and medium-sized TV monitoring system do not exceed 32, and the cost is mostly tens of thousands to hundreds of thousands of yuan.

1. 2. 1 Simple fixed-point monitoring system

The simplest fixed-point monitoring system is to install a fixed-point camera (the camera is equipped with a fixed-focus lens) on the monitoring site, and transmit the video signal to the monitor in the monitoring room through the coaxial cable. For example, a camera is placed at the gate of a small factory, and the video signal is transmitted to the monitor (or TV) in the factory office through the coaxial cable, and the manager can see who is late for work or leaves early. Whether the items in the factory were carried at the factory. If you configure another video recorder, you can also record the monitoring screen for future retrieval and verification.

This simple fixed-point monitoring system is suitable for a variety of applications. When the number of cameras is large, it can be monitored by multiplexer, screen splitter or system host. Take the headquarters of a famous foreign company as an example. The headquarters has lost high-end laptop computers many times. Later, all 12 exits on its floors were equipped with fixed-point cameras and equipped with three four-screen splitters and 24-hour real-time video recorders To prevent the above-mentioned theft.

A guest house also uses this simple fixed-point monitoring system. This is to install a fixed-point black and white camera at each end of the guest room channel on the 1st to 6th floors, plus a total of 16 cameras at 4 monitoring points such as the entrance, hall, back door, and parking lot, and then configure a 16-screen splitter, A 29-inch large-screen color TV and a 24-hour video recorder constitute a complete monitoring system.

When the number of monitoring points increases, the system scale will become larger, but if there is no other additional equipment and requirements, this type of monitoring system can still be classified as a simple fixed-point system. Take the CCTV monitoring system of a supermarket as an example. The business area is large (the upper and lower two floors total about 16000?), The shelves are more, and a total of 48 fixed-point black and white cameras are installed. The signals of these 48 cameras were divided into 3 groups, which were respectively connected to the corresponding 16-screen splitter, 17-inch black and white monitor and 24-hour video recorder (the supermarket's actual project additionally added an anti-theft alarm system and public broadcasting / background music System, omitted here). Figure 1-2 shows the composition of the supermarket TV monitoring system.

1. 2. 2 Simple all-round monitoring system

The omni-directional monitoring system is to replace the fixed-focus lens in the aforementioned fixed-point monitoring system with an electric zoom lens, and add an omni-directional pan / tilt (two motors inside the pan / tilt) that can move up, down, left, and right, so that the camera at each monitoring point can For the up, down, left, and right saccades, the focal length of the lens equipped with it can also be changed within a certain range (the surveillance scene can be zoomed in or out). Obviously, the movement of the gimbal and motorized lens needs to be controlled by the controller or the decoder that cooperates with the system host.

Compared with the simplest fixed-point monitoring system, the simplest omnidirectional monitoring system adds an omnidirectional pan-tilt head and electric zoom lens to the front end, and a controller such as SP3801 in the control room, and from the front end to the control room A multi-core (10-core or 12-core) control cable needs to be installed. Taking the monitoring system of a small garment factory as an example, two omnidirectional cameras were installed in its garment workshop, and an ordinary TV, a switcher and two controllers were installed in the factory manager ’s office. When you need to know the workshop situation, you only need to select the screen of a certain camera through the switch, and operate the controller to make the camera scan the entire monitoring site, and you can also perform spot monitoring on a certain part.

In practical applications, it is not necessary to configure every monitoring point in all directions. Usually, only a few special monitoring points in the entire monitoring system are equipped with all-round equipment. For example, in the aforementioned fixed-point monitoring system of a guest house, it may also be considered to change the fixed-point camera that monitors the parking lot situation to an omnidirectional camera (replace the electric zoom lens and add an omnidirectional pan / tilt), and then add a control in the control room Device, so that the monitoring range of the parking lot can be expanded, not only can scan the entire parking lot, but also can monitor a certain part. Especially when advancing the lens, you can also see the license plate number. Figure 1-3 shows the system structure of adding an all-round monitoring point to the fixed-point monitoring system.

1. 2. 3 Low-cost comprehensive monitoring system

Use the sub-control keyboard SP8050 to replace the PTZ lens controller, so that the system connection line is relatively simple. SP8050 can also remotely control the switch (SP2000 series) and the screen splitter. The switcher also has an alarm function. When there is an alarm, it can automatically switch out and record the on-site camera of the alarm. In terms of cost, it is lower than the system using the system host / matrix switcher.

1. 2. 4 Monitoring system with small host

There is no strict limit on how large a system is to be equipped with a system host. Generally speaking, when the number of omnidirectional cameras in the monitoring system reaches more than 3 ~ 4, you can consider using a small system host. Although multiple single-channel controllers or a multi-channel (such as 4-channel or 6-channel) controller can also be used to control the omnidirectional camera, this requires a large number of control cables (at least one for each channel) 10-core cable), and the length of the cable will be too long (the voltage drop caused by the long-line resistance may cause the gimbal and motorized lens to slow or not move), and the entire system will appear messy.

Generally speaking, the use of the system host will increase the cost of the entire monitoring system. This is because the cost of the system host is higher than that of the ordinary switch, and the price of the front-end decoder is higher than that of the ordinary single-channel controller. However, from the perspective of wiring, each decoder and the system host are connected by a bus, so the number of cables in the system is not large (only a two-core communication cable is required). In addition, most of the integrated system hosts have alarm detector interfaces, which can easily integrate the anti-theft alarm system with the TV monitoring system. When there is a detector alarm, the host can also automatically switch the main monitor screen to the screen shot by the on-site camera where the alarm occurs. Figures 1-5 show the structure of a small TV air surveillance system using the system host.

1. 2. 5 Monitoring system with sound monitoring

It is often necessary to monitor the live sound in the TV monitoring system (for example: a bank teller system), so from the perspective of the system structure, the entire TV monitoring system consists of two parts: image and sound. Due to the increase in the collection and transmission of sound signals, in a sense, the scale of the system is equivalent to double the pure fixed-point image monitoring system, and the synchronization of the image and sound signals should be ensured during the transmission process.

For a simple one-to-one structure (camera-video recorder-monitor), as long as the monitoring head and audio transmission line are added, the video and audio signals can be displayed, monitored and recorded together. For switching monitoring systems, it is necessary to configure the video and audio synchronization switch, which can switch from the multi-input video and audio signals and output the selected video and corresponding audio signals.

1. 3 large and medium TV monitoring system

The number of monitoring points of large and medium-sized TV monitoring systems has increased. In addition to containing a large number of omnidirectional monitoring points, they are often integrated with anti-theft alarm systems. Due to the large number of video and audio signals collected in the central control room, a variety of video and audio equipment is often required to combine. Many systems also require multiple sub-control centers (or sub-control points), so the system is relatively large.

1. 3. 1 Interpretation of large and medium-sized TV monitoring system

In principle, the large and medium TV monitoring system is the same as the aforementioned small and medium TV monitoring system. The so-called "large and medium" can have two meanings: one refers to the large scale of the system, such as the number of front-end cameras and the number of central control equipment, the scene of the central control room is also very large, and often has a side The huge monitor wall can display dozens or even dozens of real-time monitoring scenes of different sizes at the same time. In addition, there are many related departments with sub-control systems, sometimes with anti-theft alarm system or access control card system Linkage; Second, the system has high complexity, difficult operation, and poor transmission conditions, making the monitoring system of more than a dozen points more difficult than the construction and debugging of the monitoring system of the same ten or even hundreds of points in ordinary supermarkets or office buildings. .

1. 3. 2 Multi-host multi-level TV monitoring system,

Conventional TV monitoring systems generally have only one host. Even large and medium-sized systems, nothing more than increase the number of cameras and increase the number of sub-control systems. However, for some special applications, this single host plus several sub-controllers can not meet the needs of users. Taking the monitoring system of a large factory as an example, the user requires a closed-circuit television monitoring system to be installed in each relatively independent factory area. Each factory area has an independent monitoring room, and the management personnel can perform arbitrary operation control on the system. The whole factory also needs to establish a large-scale monitoring system, combine the subsystems of each plant area, and set up a large-scale TV monitoring center, where you can arbitrarily view the image of a camera in a plant area, and the cloud of the camera Taiwan and electric zoom lens to control. This puts forward the requirement that a large-scale TV monitoring system should be formed by multiple hosts in each plant area.

Since the internal structure and working principle of each host are the same, compared with the ordinary matrix host, each host of this multi-host system has an address identification code added, which can be selected and adjusted by the upper-level host. The image is selected and transferred to the monitor in the control room of the main center through two-level or three-level switching.