Abstract: TV monitoring technology comes from non-broadcast TV technology. With the appearance of television, television is divided into two technologies. One is radio and television technology, which records and edits (such as TV dramas broadcast by TV stations), but it does not reflect reality and can be broadcast to the public. The other is non-broadcast TV technology, which develops synchronously with broadcasting technology. Up to now, it is not inferior to broadcasting technology in breadth and depth. Non-broadcast TV technology is also used in the field of computer TV, which is very important in the whole electronic field. Non-broadcast TV technology has developed from the beginning of the twentieth century to the present, and has completely entered the high-tech field under the impact of many technological changes. The field of non-broadcast TV (TV monitoring technology) is divided into three stages: analog stage, digital-analog combination stage and all-digital stage.

Keywords: TV monitoring system multimedia technology network transmission technology development

1, TV monitoring technology comes from non-broadcast TV technology. With the appearance of television, television is divided into two technologies. One is radio and television technology, which records and edits (such as TV dramas broadcast by TV stations), but it does not reflect reality and can be broadcast to the public. The other is non-broadcast TV technology, which develops synchronously with broadcasting technology. Up to now, it is not inferior to broadcasting technology in breadth and depth. Non-broadcast TV technology is also used in the field of computer TV, which is very important in the whole electronic field. Non-broadcast TV technology has developed from the beginning of the twentieth century to the present, and has completely entered the high-tech field under the impact of many technological changes. The field of non-broadcast TV (TV monitoring technology) is divided into three stages: analog stage, digital-analog combination stage and all-digital stage. The initial CCTV monitoring system in the analog CCTV stage is simple and large-scale. There is no central control equipment in the whole monitoring system, and every monitoring is realized by a camera corresponding to a TV. There are as many cameras and televisions as there are surveillance places. For example, in Chaplin's time, there were many vacuum tube TVs and vacuum tube cameras in the factory director's office. A camera is pointed at a place, and there are 100 workshops. It takes 100 TV sets to see the images of each workshop. Its characteristics are: real-time, used for specific purposes, the image is not modified, it directly reflects the essence of the system, but this technology is both wasteful and easy to bring fatigue. In the 1960s, with the advent of microprocessors, TV monitoring can switch camera images and further control the pan/tilt, and control the positioning and tracking of the pan/tilt. However, due to the limitation of single chip microcomputer, the functional capacity and running speed of the system are limited and it is easy to crash. In the stage of digital-analog combination, due to the enhancement and improvement of the functions and performance of microprocessors and microcomputers, the emergence of various special LSIC and ASIC, and the application of multimedia technology, the functions, performance, reliability and structure of system control equipment have changed greatly, the composition of application TV system is more convenient and flexible, the interface with other technical systems tends to be standardized, and the human-computer interaction interface is more friendly. At this stage, the TV monitoring host can realize the following functions: 1, audio-visual matrix switching 2, remote control 3, alarm input and linkage; 4. Video information superposition. Many scientific research units and manufacturers at home and abroad are actively developing system hosts. Representative systems are: American AD, PELCO, VICON, ADEMCO, JAVELLIN, PHILIP, Panasonic of Japan, etc. Technical features: analog switching, multimedia console management and computer coordination. International and domestic level: the typical analog matrix host system is mainly developed internationally, and the typical technologies such as analog matrix switching are mature technologies. The system is also made in China, but there is a gap in the isolation of analog signals. In the multimedia monitoring system of computer image processing, which is changing from analog system to digital system, domestic products started early and the technical level was low. In this paper, the author led the development of the earliest multimedia monitoring system in China at 1992- 1993, which was two years ahead of similar products abroad, and its performance far exceeded that of American ad, JAVELLIN and other multimedia monitoring systems. Successful promotion in China has a great impact. With the development of TV monitoring technology, it can be said that the classic application TV system with camera technology as the core has reached a high level, and the camera technology, transmission technology and system control technology have made great progress. The appearance of CCD camera and optical fiber communication technology is epoch-making, which has greatly changed the face of applied TV, but these changes are not revolutionary as far as applied TV is concerned. There is no essential catch-up between the classic mode of applied TV and the monitoring system in the American film Modern Times directed by Chaplin: (1) The information flow form in the applied TV system has not changed, and it is still an analog video signal. (2) The network structure of the system has not changed, and it is mainly a single-function, one-way and lumped information collection network characterized by special media. (3) The working mode of the application TV has not changed, and the image is mainly displayed through the video monitor, and the direct observation of people is used as a method (information sink) to extract swimming information from the image. (4) The control equipment of the system is mainly front-end management (front-end equipment control and remote control, signal distribution and switching). During the whole process, the video signal output by the camera is basically not processed. Therefore, the classic application TV system is centered on the camera (imaging technology). (5) For the important remote transmission function, the existing technology is still analog private line transmission. To sum up, non-broadcast application TV system is in the transition stage to digital system, and it is a mixed digital-analog application TV system. All-digital analog video equipment has developed to a very high level and has no potential to be tapped. To meet higher requirements, digitalization is the only way. Digital signal has the characteristics of high spectral efficiency, strong anti-interference and small distortion, and is also the premise of image processing such as compression processing. Digital TV monitoring system has innovated the theory and technical route of all-digital non-broadcast application TV system, and comprehensively applied image processing technology, active video processing technology, network communication technology and network streaming media broadcasting technology. The new generation of digital video host and DVR have reached a new level. Related nouns What is multimedia? Multimedia technology is aimed at a single media. Video is an independent media. From the computer's point of view, it is a character terminal, a very rough character, and there is no connection between them. Now technology is merging these single media. Seeing moving videos, real-time sounds and changing words on the computer and displaying them in a fused way, all images, sounds and words are fused in real time, which is called multimedia. The combination of multimedia and network. Network transmission technology uses digital technology to transmit remote scene images to the desktop. Several important standards on the network: telephone line: H.324 network: H.323 network protocol: TCP/IP video recording system technology used to be video tape, with limited storage capacity. A tape can be recorded for 3 hours in real time, but it can't record continuous images with long delay, so many tapes need to be stored. Now with digital video recording technology, a small disk can record completely real-time images, and the hard disk is easy to save, which embodies the height, precision and sharpness. 2. Technical indicators related to digital TV monitoring (taking bank teller monitoring as an example) Monitor the clarity of the main interface ● Video recording and display can reach 768*576 image quality; ● Video shooting is 384*288, and playback can reach 704*576 resolution; ● Any local stepless electronic amplification can be performed during playback, and details can be clearly seen when searching and recording frames. Real-time performance of the system ● Display, playback and video recording can be carried out at the same time, and real-time display, real-time video recording and real-time playback of 25 frames/second should be realized in any way. System reliability ● Less resources are occupied, and the single CPU system works reliably and smoothly; ● It comes with complete password image protection function, which is safe and reliable; Software and hardware watchdog double insurance to ensure that the system does not crash. Digital multimedia monitoring system function ● Monitor VHS quality in real time with 16 channel ***480 frames/second; ● Stand-alone 16 channel ***480 frames/second, and hard disk video recording, which will not affect the video quality when playing; ● Video recording can be pre-recorded 5 seconds in advance; ● Video data can be captured and stored at will during playback; ● Unique functional software cannot handle details clearly; ● Hardware image alarm function, software video alarm, dual-function disconnection prevention, 8-way isolation and 8-way IO; ● Large compression ratio: 50-450m/h for video and 40m/h for audio. ● Multi-channel audio-visual synchronous real-time recording, single-channel audio-visual synchronous playback, each with its own sound. Relevant technical indicators of multimedia matrix host ● Magnificent image acquisition capability, realizing single-machine simultaneous acquisition of 1- 128 audio and video signals, and matrix input can be extended to 1024 channels; Powerful image processing function, which can easily control all kinds of complex systems at the same time. 1) A single machine can process at most 128 images at the same time, and realize the simultaneous display of single-screen 1- 128 high-definition images. Every picture is real-time and can be enlarged to VHS quality. (2) Single machine and single screen display 1- 128. At the same time, the host can handle 1- 128 image alarm and hard disk video recording at the same time. The three functions do not interfere with each other when processing at the same time, and the display/recording/playback are all VHS real-time images, with 25 frames per second; ● Split-screen control technology breaks through the limit: Matrix output can not only display 4 /8 /9/16 HD pictures on every unit of TV wall (such as monitor) at the same time, but also realize 4 /8 /9/16 HD pictures on the local split-screen control and network split-screen control of Walker multimedia matrix host. ● Powerful network function: In addition to working independently, each host also supports network monitoring of multiple hosts. Comparison between analog system and digital system 1. The analog monitoring system is an analog series with video matrix, divider and video recorder as the core, supplemented by other sensors. Traditional monitoring systems can only use special mechanical video recorders and tape recorders. The typical structure of the existing system: the front end: fixed camera, spherical high-speed pan/tilt, infrared detector and other centers; Matrix switching host output: monitor, video recorder, printer, leading analog signal keyboard, etc. 2. Digital monitoring system is a new video monitoring system with computer technology and image and video compression as its core, which is composed of computer, camera and network equipment (modem, ISDN, network card, etc.). ), video compression acquisition, infrared detector, controller, image coding and decoding software and communication software package. From the above analysis, it can be seen that the banking industry has an urgent need for digital security monitoring system. It is the general trend to combine digital monitoring system with Internet to replace analog monitoring system. At present, the analog monitoring compression technology, DSP (digital signal processing) processing technology and FPAG application technology have been innovated, and combined with the Internet, it should have a very broad prospect to develop into the field of remote wireless digital monitoring and biometrics. Four. The transformation of TV monitoring system from analog system to digital system. Analog video equipment has developed to a very high level, and there is no potential to be tapped. To meet higher requirements, digitalization is the only way. Digital signal has the characteristics of high spectral efficiency, strong anti-interference and small distortion, and is also the premise of image processing such as compression processing. 1. The analog monitoring system is mainly based on analog signal processing technology, which has some limitations, such as: ● The transmission distance of analog video signal is very sensitive, and when the transmission distance exceeds 1000 meters, the signal is prone to distortion and attenuation; ● Monitoring networking is difficult, and only point-to-point on-site monitoring can be carried out; ● Although a long delay video recorder is used, it still needs a lot of storage media; ● Due to the point-to-point monitoring mode, the amount of wiring is large and the cost is high, so it is impossible to use the ready-made LAN system; ● Although remote monitoring can be realized by wireless means, the cost is generally high and the reliability is not ideal. 2. Digital CCTV monitoring system adopts digital technology and computer network technology, which overcomes the above limitations of analog system. Its advantages are as follows: ● Due to the adoption of digital signal processing technology, digital video signals and audio signals are not easily disturbed by the outside world, and the signal quality is easy to ensure; Due to the adoption of networking technologies such as computer local area network and wide area network, the monitoring distance of digital multimedia remote network is not limited by distance; ● Due to the adoption of large-capacity disk array memory or optical disk memory, a large number of magnetic tape storage media can be saved, which is beneficial to the system to realize multimedia information query; ● Digitalization is a recognized development direction in all fields of the world. The adoption of digital multimedia remote network monitoring conforms to the technical development trend of digitalization, networking and intelligence. To sum up, non-broadcast application TV system is in the transition stage to digital system, but the existing product development plan in the world is not a shortcut to digitalization, but a mixed digital-analog application TV system. The key point is that although digital devices such as digital cameras and digital multi-screen display processors have been applied, the input/output signals of connected devices are still analog signals, which have the limitations of resolution and speed of analog signals. It is urgent to transition to all-digital systems to solve the above problems. V. Development Status of Digital TV Monitoring System Products At present, various manufacturers at home and abroad have introduced different hard disk video products, such as hard disk video systems with M-Jpeg or H.26 1 as the mainstream compression mode from European and American manufacturers, Mpeg- 1 compressed products from South Korea, imported products from domestic OEMs, Japan and South Korea, and video products developed by domestic manufacturers. There are many good products with high cost performance, but some products do not have excellent technical indicators and professional monitoring functions, but make a fuss about the surface indicators of products and mislead consumers. Hard disk video recording system is a high-tech product, and the quality of a hard disk video recording system needs to be measured from the following angles: compression algorithm At present, the common compression algorithms of hard disk video mainly include MJPEG, MPEG, H.26 1 and so on. The following is a comparison of these methods. MJPEG is a simple intra JPEG compression. Although there is no mosaic phenomenon, it cannot be compressed on a large scale due to the technical limitation of this method. Video recording space is per hour 1-2G, and network transmission requires 2M bandwidth. So using this method, both video recording and network transmission will consume a lot of hard disk and bandwidth. Unless there is a special monitoring network, it is not suitable for online monitoring video of banks. MJPEG hardware support is not extensive, and it is difficult to guarantee the maintenance and upgrade of equipment. H.26 1 is an intra-frame compression algorithm based on pre-and post-frame prediction. Because only the last 1 frame is predicted, it has an advantage in delay speed and can achieve a relatively small delay, but it is difficult to achieve high definition in image quality, and it has no advantage in video recording, and it is impossible to achieve video recording with large compression ratio and variable rate. Mpeg- 1 is a multi-frame prediction compression algorithm, which has great compression flexibility, can compress real-time video at a rate as low as 256K, and can save storage space during variable-rate compression (dynamic detection), so the video space varies from 80M/ h to 400 m/h according to different video environments, and different compression qualities can be set according to different occasions, so it is the first choice for hard disk video recording at present. Hard disk video with monitoring function is a sharp weapon for bank evidence collection, but if the video recording system is only video recording, its flexibility will be greatly reduced. Professional hard disk video recording host should at least have alarm input and output and various pan-tilt control functions, so as to automatically start video recording and control the camera to record at a predetermined position in case of an accident. If it has matrix control function, it will give full play to the function of hard disk video recording and realize network remote monitoring and video recording. Support for sound If you "only see the person, but can't hear his voice", then the video recording system is only perfunctory to the user. There is no reason to mute the video of the bank. How to save sound and synchronize playback while recording multi-channels? This has always been a problem in this industry. At present, there are not many products on the market that can solve simultaneous video recording with sound, and it is rare to solve simultaneous video recording with multiple sounds. At present, the DS25 series hard disk video recorder introduced by Walker Company has the function of 16 channels of sound synchronous recording, and this technology has reached the advanced level in the industry. Due to the limitation of foreign chip technology, some other Korean products can only record 8 channels of audio. Some early products didn't even have sound support or could only rely on computer sound cards to keep one sound, and some manufacturers mixed multiple sounds into one sound through mixing equipment to solve the most professional needs in the most unprofessional way! Remote video recording supported by network is a newly developed video recording method, which can ensure that the recorded things will not be destroyed. Smart criminals don't leave any clues, but who knows that all the crimes have been spread to remote places through the internet and preserved? Therefore, the remote video recording function will be widely used in the financial security system of network monitoring. At present, some manufacturers can't solve the technical problems themselves and can't guarantee the long-term continuous normal operation of the system, so they use manual control to restart the system regularly. Although this hardly affects the normal operation of the system, it is impossible to record during the startup process, but it is indeed a security loophole, and perhaps the critical moment will occur during the restart process. Therefore, it is not advisable to obtain stable guarantee in this way. The price factor depends on price, so it depends on cost. From the source of products, there are three kinds of hard disk video products on the market at present: 1) direct reference to foreign products or OEM products with domestic brands, (2) secondary development products assembled by domestic manufacturers, (3) boards and application software developed by domestic manufacturers themselves, which should be (1) > (2) > ③, so the prices are the same. Therefore, under the premise of equivalent technical content, the products developed by domestic manufacturers should have the highest cost performance, and because all technical cores are developed by themselves, they have unparalleled advantages in maintenance cycle and parts update. Relevant considerations when intransitive verbs choose digital TV monitoring system. The technical factors of system selection can test the level of central system from the following four aspects: Does the system use multimedia technology? How many multimedia technologies are there? Is the system designed for local or network? Video recording system is the latest digital system, digital hard disk video recording system or video recording system? Do you consider the comprehensiveness of public security work and whether it is a comprehensive system? How integrated is it? There are also four indicators: is the product reliable and meets the national standards? Is it in line with the development trend? Is the product advanced? Is the application flexible and can it be applied to other fields? Does it conform to the trend of computerization and networking and integrate the command center? 2. Digital video technology should have the following characteristics: (1) The central controller of the digital integrated CCTV system should be compatible with all the functions of the analog system, and has been used to and tested by practice. That is, digital processing, image detection, recognition and control are performed while managing multi-channel video through digital methods. At the same time, different video streams must be processed at the same time, network transmission and storage are supported at the same time, and the data stream mode can be switched, so it can no longer be converted into video. (2) To have the full digital remote image transmission function, we must reach the image quality of the analog system-the analog system is used to its uncompressed definition. That is to say, high-resolution image compression/decompression must be realized by digital method, and it should be able to adapt to various communication lines. At the same time, multiple groups of video streams must be transmitted at the same time, received and switched by data streams, and cannot be converted into video. (3) All-digital video recording technology must be compatible with and surpass all the functions of analog systems-analog systems have long been used to video recording, that is, multi-channel videos must be recorded simultaneously by digital methods, and retrieved, processed and played back separately. (4) Full-digital display technology The multimedia operating system must be compatible with and surpass the analog multi-screen display function, so as to realize the display with various definitions including high definition. Single digital image technology is easy to realize. When multiple multimedia operations are carried out concurrently, it is a key problem to have a specially designed multimedia operating system schedule. (5) Research on cross-platform architecture of all-digital system. The leading monitoring terminal must be able to apply various computing platforms, not only designed for PCX86 architecture, but also take care of civilian non-professional users, such as non-professional users who use ordinary TV, and can enjoy the existing technology without changing TV and work habits. Attachment: The application of digital multimedia related application (1) in political security requires the development of both police force and criminal technology. It reflects the performance and achievements of leaders. Criminals have used high-tech means to commit crimes. It is a modern organization, modern equipment, and a very prominent crime. It is necessary to demand technology from the police force and improve the importance of applying technology to the police. If online shopping is used, a large number of illegally obtained funds are paid through the Internet, and online shopping has no invoices and accounts, and illegal income is sold online and converted into legal income. Criminal means have entered high technology. If public security personnel want to achieve the magic height of one foot and ten feet, they must arm themselves with higher technology and take the lead in letting themselves enter new technical fields. (2) The emergency response of the public security department is the top priority. After the emergency, there are loopholes in the original telephone, video tape and written report, which can't convey information in time, but images can convey important information at any time. (3) Applications in economic insurance: image storage, long-term video recording, robbery prevention, theft prevention, remote image monitoring of cash-carrying vehicles ... Comparison of various remote image transmission means ... The long-term video recording and robbery prevention means of banks can accurately record video for a long time and obtain accurate evidence. In the past, video tape was used to record video, which required a lot of tapes, because the analog mode did not compress the image and the image size was large, so there were many tapes. Moreover, after the video recorder repeatedly reads and writes, the magnetic head needs to be cleaned, the tape image will become more and more blurred, and the tape will become moldy in wet places. There is a case in Hunan. The gangster robbed a bank in Hunan and went to Guangdong to save money. Banks in Guangdong have installed video systems and recorded their images. Hunan police went to Guangdong to handle a case, found the bank, immediately recognized the customer from the retrieved image, and soon solved the case. Video recording system is very important, it provides strong evidence, and this kind of recording can only be well used through digital technology. (4) armored car system In the past, armored cars used GPS system to know the specific location of the car at any time, but they couldn't see the inside of the car. In view of the large number of cases of armored vehicles, it is very difficult to solve the case because the command center does not know the situation inside the vehicle. The former technology can't solve it, because the simulation technology relies on infinite electric emission and microwave emission. Because the microwave emission is linear, it is impossible to see the image when the car is walking in the building. Now you can put it in the car with VCD. When the car is walking, the center can receive images and know what is happening in the car. (5) Application in criminal investigation: on-site fingerprint collection, transmission, remote database comparison, blurred image post-processing, ... Image digital watermark anti-counterfeiting technology (6) Application in traffic: If an illegal vehicle runs a red light in the electronic police system at night, the police don't have to intervene, and the digital camera automatically captures the illegal vehicle and transmits it to the center. Every month, traffic personnel can check the records and issue illegal fines to illegal car owners. In the past, with traditional technology, it was not clear to capture photos at night. Although there are many photos, there are few effective photos. Using a digital camera to shoot the front of the car can get high-definition images even at night. Avoid the problem that people can't see clearly because the car lights are on. Similarly, on the expressway, at the junction of Henan and Hubei, many vehicles pass by every day. There used to be accident vehicles running between two cities. After this system is equipped, if it is a vehicle that caused an accident in Henan, it can be found that the illegal vehicle is now in Hubei by querying the database, and Henan public security personnel can directly query in Hubei Province through the network, which greatly saves time. (7) Application of unclassified new technical fields: license plate recognition, face recognition, application of mobile phone positioning in automobile management, automobile management and tracking; Application of digital anti-counterfeiting technology; The application of WEB-based crime database: the application of videophone and network video conference; The application and management of interactive TV/TV broadcast VOD in training and other fields can be divided into three parts: car management and mobile phone management.