Brief introduction of monitoring system equipment
â‘ Gimbal In the previous introduction, we often mentioned the gimbal, but some people have no perceptual knowledge about it. In fact, the gimbal is an installation platform composed of two alternating currents, which can move horizontally and vertically. What we call the gimbal is different from the gimbal in the camera equipment. The gimbal of the camera equipment is generally just a tripod, which can only be adjusted by hand; the gimbal of the monitoring system is at the far end through the control system. Can control the direction of rotation. There are many types of gimbals: There are indoor and outdoor types according to the use environment. The main difference is that the outdoor type has good sealing performance, waterproof, dustproof, and heavy load. According to the installation method, it is divided into side installation and ceiling installation, that is, whether the gimbal is installed on the ceiling or on the wall. According to the shape, it is divided into ordinary type and spherical type. The spherical gimbal is placed in a hemispherical and spherical protective cover. In addition to preventing dust from interfering with the image, it is also concealed, beautiful and fast. When selecting the gimbal, you must consider the installation environment, installation method, working voltage, and load size, as well as the price-performance ratio and whether the appearance is beautiful.
②Bracket If the camera is only fixed to monitor a certain position without turning, then only the camera bracket can meet the requirements. Ordinary camera brackets are simple to install, inexpensive, and have a wide variety. Ordinary brackets are short, long, straight, and curved. Choose different models according to different requirements. The outdoor bracket mainly considers whether the load capacity meets the requirements, and then there is the installation position, because from practice we have found that many outdoor cameras are installed in special positions, some are installed on telephone poles, some are standing on tower cranes, and some are installed on iron On the shelf ... For various reasons, the existing bracket may be difficult to meet the requirements, and additional processing or improvement is required, so I wo n’t go into details here.
â‘¢Protective cover Protective cover is also one of the most commonly used equipment in monitoring system, mainly divided into indoor and outdoor. The main difference between indoor protective cover is the size, whether the appearance is beautiful, and whether the surface treatment is qualified. The function is mainly to prevent dust and damage. The sealing performance of the outdoor protective cover must be good to ensure that rainwater cannot enter the inside of the protective cover to erode the camera. Some outdoor protective covers are also equipped with exhaust fans, heating plates, and wipers to better protect the equipment. When the weather is too hot, the exhaust fan works automatically; when it is too cold, the heating plate works automatically; when there is rain on the protective cover glass, the wiper can be activated through the control system. When selecting the protective cover, first look at the overall structure. The fewer the installation holes, the better the waterproof. Then look at whether the internal wiring is easy to connect. Finally, you need to consider the appearance, weight, mounting seat, and so on.
â‘£Monitor The monitor is the standard output of the monitoring system. Only with the monitor can we view the images sent by the front end. The monitor is divided into color and black and white, and the sizes are 9, 10, 12, 14, 15, 17, 21 inches, etc., the commonly used is 14 inches. The monitor also has a resolution, which is expressed by the number of lines as the camera. In actual use, the number of lines of the monitor is generally required to match the camera. In addition, some monitors also have audio input, S-video input, RGB component input, etc. In addition to the audio input monitoring system, the rest of the functions are mostly used for image processing, and will not be described here.
⑤ Video amplifier When the video transmission distance is relatively long, it is best to use a thicker video cable, and at the same time can increase the video amplifier in the line to enhance the signal strength to achieve the purpose of long-distance transmission. The video amplifier can enhance the brightness, chroma and synchronization signal of the video, but the interference signal in the line will also be amplified. In addition, too many video amplifiers cannot be connected in series in the loop, otherwise saturation will occur, resulting in image distortion.
â‘¥ Video distributor One channel of video signal corresponds to a monitor or video recorder. If you want to send the image of a camera to multiple managers, it is best to choose a video distributor. Because of the large attenuation of the parallel video signal, the image will be severely distorted due to impedance mismatch and other reasons after being sent to multiple output devices, and the line is also unstable. In addition to impedance matching, the video splitter also has video gain so that the video signal can be sent to multiple output devices simultaneously without being affected.
⑦Multi-channel video signal of the video switcher should be sent to the same place for monitoring. One channel of video corresponds to one monitor, but the monitor occupies a large area and is expensive. If you do not require constant monitoring, you can add a switch in the monitoring room The output signal of the switch is connected to the input terminal of the switch, the output terminal of the switch is connected to the monitor, the input terminal of the switch is divided into 2, 4, 6, 8, 12, 16 channels, and the output terminal is divided into single channel and Two-way, but also can switch audio simultaneously (depending on the model). The switcher has two working modes: manual switching and automatic switching. The manual mode is to switch the switch to the desired way; the automatic mode is to delay the preset video in sequence, and the switching time can be adjusted by a knob. Generally between 1 second and 35 seconds. The price of the switch is cheap (generally only three or five hundred yuan), the connection is simple, and the operation is convenient, but only one image in the input can be seen in a time period. To view multiple camera images on one monitor at the same time, you need to use a picture splitter.
⑧ Screen splitter There are four types of screen splitter: nine, sixteen, and sixteen. The images of 4, 9, and 16 cameras can be displayed on one monitor at the same time, and they can also be sent to the recorder for recording. Quad-segmentation is one of the most commonly used equipment, its performance and price ratio is also good, and the quality and continuity of the image can meet most of the requirements. Nine-segmentation and sixteen-segmentation are more expensive, and the resolution and continuity of each image will be reduced after the division, and the recording effect is not good. In addition, there are six-segment, eight-segment, and double-four-segment devices, but the image ratio, sharpness, and continuity are not ideal, and the market utilization rate is smaller. In addition to displaying images at the same time, most of the splitters can also display a single picture, which can superimpose time and characters, set automatic switching, and connect to alarm equipment.
⑨The most commonly used recording equipment in the video recorder monitoring system is civilian video recorders and long delay video recorders, because the operation is simple and easy to learn, and the video tape is also easy to save and buy. Different from home video recorders, delayed video recorders can work for a long time, can record 24 hours (using ordinary VHS video tapes) or even hundreds of hours of images, can be connected to alarm equipment, and automatically start recording when the alarm signal is received. Automatic recording program of the recorder, choose the recording speed, whether the video tape automatically stops or rewinds when it reaches the end ... Although the performance of the delay recorder is outstanding, it is expensive, and the current resolution is not very high. A part of it will be lost, and the playback images are skipped one by one.
Introduction of front-end monitoring equipment
Camera: Adopting advanced charge-coupled device CCD image sensing technology. Cameras with automatic iris interface, automatic white balance, electronic shutter, illumination requirements, backlight compensation, standard definition or high resolution image are suitable for users to choose from. It can be divided into:
Black and white camera: economical and practical, with superb clarity and sensitivity;
Color camera: high-definition and color form a sharp image contrast;
Hemisphere black and white / color camera: economical and convenient, with its own lens and mounting bracket, which can be coordinated with the surrounding atmosphere;
Lens: By changing the lens to adjust the camera range to obtain a suitable image, the lens can cooperate with a series of cameras. Divided into: fixed focus lens and zoom lens. Fixed-focus lenses are available in wide-angle, standard, and long focal lengths. You can also choose a manual iris lens suitable for places with constant lighting conditions or an automatic iris lens suitable for places where lighting changes frequently; Field of view requirements.
Infrared light projector: Provides the lighting needed for the camera to work at night.
Camera protective cover and bracket: Effectively prevent man-made damage to the camera, play a role of waterproof, dustproof, fixed. Omni-directional pan / tilt: It can rotate up, down, left and right to realize all-round surveillance.
PTZ lens controller: remotely control the on-site pan-tilt rotation and adjust the focal length and aperture of the camera lens.
Monitor head: While monitoring the live image, you can monitor the live sound with high sensitivity.
Monitor: Displays the image picked up by the camera with high quality. There are multiple sizes of black and white and color monitors to choose from.
Introduction of terminal monitoring equipment
Sequential video and audio switcher: It can switch the camera images and corresponding audio signals from 2 to 12 channels in sequence, and the timing switching image signals are automatically displayed on the monitor in sequence, and the switching time can be adjusted. You can also manually switch the selection or bypass to isolate the image display of a certain designated camera.
Video image processor: With the video image processor, multiple images can be split and displayed on a monitor screen at the same time, or one of the multiple images can be selected for full-screen display. With alarm input interface, it can automatically switch to display the full-screen image of the corresponding camera when alarming. More advanced model processor with video playback control function.
Matrix switching controller: pre-programmed to control video and manage alarm input and output.
Professional video recorder: Use a box of ordinary household video tapes to conveniently record all the camera images and audio signals of the system for 24 hours or even 168 hours up to 960 hours, and the management is simple and convenient; during video playback, with the video image processor, it can display multi-screen segmentation The image can be manually switched to display the full-screen image of a certain camera; abnormal image confirmation can be performed in high-speed playback; when the alarm signal of the sensor is received, the recorder can be automatically started or switched to the real-time recording state; the monitor displays the operating program and function menu.
Mobile Phone Headset is a pair of switching units that accept the electrical signals from a media player or receiver and convert them into audible sound waves using a speaker close to the ear. The headset is typically detachable from the media player and is connected by a plug. The advantage is that you can listen to the sound alone without affecting others; you can also separate the sound of the surrounding environment.
Mobile phone headset maintenance and care notes:
1: Be sure to lower the volume before use. If the volume of your output device is too large, not only damage ears, but also diaphragm folds, or even burne the voice coil of the earphone.
2: The earphones are away from strong magnets. The magnetic properties of the magnet of the unit will drop, and the sensitivity will decrease over time.
3: The earphones are away from moisture. The pads in the earphone unit will be rusted, the resistance will increase, and your earphones will be biased.
4: Keep away from chemicals. The outer casing of the earphone is very soluble in organic chemicals, so it is not good to look at it.
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