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What are “PAL format” and “NTSC format”, “field” and “frame”?

What are PAL format and NTSC format, field and frame

“PAL” and “NTSC”

Although the issue of “standard” is not mentioned much now, it is a very important concept in the era of analog video surveillance, just like the basic standard of whether a motor vehicle runs on the left or on the right.

PAL (Phase Alternating Line) is a TV system established in 1965 and is mainly used in China, Hong Kong, the Middle East and Europe. The color bandwidth of this format is 4.43Mz, the audio bandwidth is 6.5MHz, and the picture is 25 frames per second.

The NTSC (National Television System Committee, National Television System Committee) format is a color television broadcasting standard formulated by the National Television Development Committee of the United States in 1952. The United States, Canada, as well as China Taiwan, South Korea, the Philippines and other countries use this format. The color bandwidth of this system is 3.58MHz, the audio bandwidth is 6.0MHz, and the picture is 30 frames per second.

The reason why the NTSC system is 30 frames per second and the PAL system is 25 frames per second is because the mains electricity in the countries where NTSC is adopted is 110V/60Hz, so the field frequency signal in the TV directly samples the frequency of the AC power supply at 60Hz. Because two fields make up one frame, 60 divided by 2 equals 30, which is exactly the number of frames of the TV, and China’s mains electricity is 220V/50Hz, so the reason is the same as the above is 25 frames per second.

“Field” and “Frame”

In traditional CRT analog TV, a line scan, scanning in the vertical direction is called “field”, or “field scan”. Each TV frame is produced by scanning the screen twice, with the lines of the second scan filling the gaps left by the first scan. So a TV picture of 25 frames/s is actually 50 fields/s (30 frames/s and 60 fields/s respectively for NTSC).

The idea of “frame” comes from the early movies, a still image is called a “frame” (Frame). The picture in the film is 25 frames per second, because the persistence of vision of the human eye just meets the standard of 25 frames per second. Generally speaking, the number of frames, simply put, is the number of frames of pictures transmitted in 1s. It can also be understood that the graphics processor can refresh several times per second, usually expressed in FPS (Frames Per Second). Each frame is a still image, and displaying frames in rapid succession creates the illusion of motion. Higher frame rates result in smoother, more realistic animations. The more frames per second (fps), the smoother the motion displayed.

When a computer plays a video on a monitor, it just displays a series of full frames, without the TV trick of interleaving fields. So neither video formats nor MPEG compression techniques designed for computer monitors use fields. Traditional analog systems use a CRT monitor (similar to a TV) for monitoring, which involves “fields” and “frames.” The digital system uses LCD or a more advanced display (similar to a computer display) to process images using computer technology, so it only involves “frames”, which is also the difference between a digital monitoring system and an analog monitoring system.

Even in the era of artificial intelligence, “frame” is still a very important concept, and how to extract effective “frames” in continuous pictures is crucial. When extracting features of the same face, license plate, human body, and vehicle, how to avoid repeated extraction and extract the clearest picture lies in the “frame extraction” technology.

Four eras of video surveillance system development

Four eras of video surveillance system development
Four eras of video surveillance system development
Four eras of video surveillance system development

Since 2017, people have clearly felt that they are in the fourth industrial revolution. The core of the revolution is artificial intelligence. No AI is not safe, no AI is not smart, and no AI is not video. Artificial intelligence has been developed for more than 70 years, and the real historical impact on the development of video surveillance systems was in 2017. 2017 can be called the first year of this era. The commercial mature application of face recognition technology is the detonation of the birth of this era. point.

Summarizing the development history of video surveillance for more than 60 years, the development of video surveillance can be roughly divided into four eras: the analog era, the digital era, the intelligent era, and the data era.

①The simulation era (1957-2004)
3 see: invisible, unclear, unintelligible
There are three characteristics of the simulation era:
Invisible. Limited by many factors such as cost, technology, etc., many places where monitoring equipment should be installed in the simulation era are not installed, which makes it invisible.
Can’t see clearly. The resolution of analog surveillance is based on TV. 380TVL, 420TVL, 480TVL, and 540TVL are all mainstream resolutions, which are far below the standard of high-definition surveillance. It is more obvious after the analog conversion (the lossy compression of DVR hard disk video recorder is especially obvious).
can not read. The analog video signal has almost no analysis and intelligent functions, and usually realizes the motion detection function of the picture (full picture or partial area).
The main functions of video surveillance in the analog era are surveillance, recording and playback of recordings.

②Digital era (2004-2017)
4 Full: full domain coverage, full network sharing, full-time availability, full-process controllable
Thanks to the advancement of network technology and IT technology, the digital era has improved some of the shortcomings of the analog era, with the following four characteristics:
Global coverage. The video surveillance coverage of key public areas will reach 100%, and the proportion of newly built and rebuilt HD cameras will reach 100%; the video surveillance coverage of important parts of key industries and fields will reach 100%, and the number of new and rebuilt HD cameras will be gradually increased.
Shared across the network. The video surveillance networking rate in key public areas reaches 100%; the video image resource networking rate in key industries and fields involving public areas reaches 100%.
Available all time. The integrity rate of video surveillance cameras installed in key public areas reached 98%, and the integrity rate of video surveillance cameras installed in key industries and fields involving public areas reached 95%, realizing the all-weather application of video image information.
The whole process is controllable. The hierarchical security system for networked applications of public security video surveillance systems has been basically completed, so that important video image information is not out of control, and sensitive video image information is not leaked.
The digital age has expanded large-scale cluster applications, emphasizing coverage and large-scale networking applications, making each “closed-circuit” surveillance system a powerful video surveillance resource network.

③The era of intelligence (beginning in 2017)
3 See: can see, see clearly, understand
Thanks to the development of artificial intelligence technology, video surveillance has undergone qualitative changes after entering the intelligent era:
visible. In the case of global coverage, video surveillance is basically covered without blind spots to ensure that video can be seen in every place that needs to be monitored. Video surveillance is like human eyes to the city, otherwise there will be management blind spots.
Can see clearly. At present, the cameras used in mainstream applications are all networked, with pixels up to 2 million, 3 million, resolutions up to 1080P or 4K, or even higher resolution (such as 8K), and there are also cameras with large viewing angles such as panoramic and fisheye to ensure The picture you see is high-definition, wide, and can be used for intelligent analysis.
understand. Thanks to the development of computer perspective technology such as license plate, vehicle, face, human body, and object feature recognition in the past two years, the computer can automatically recognize this video or image with functions similar to the human eye, and has human brain intelligence.
In the intelligent era, video surveillance already possesses part of the functions of the human brain to realize video analysis and intelligent applications.

④The era of data (starting in 2018)
4 Full: panoramic data, full data, global data, holographic data
Cloud computing and big data are no longer fashionable vocabulary, they have penetrated into all aspects of social governance. After unstructured video image data is structured, big video image data can be formed. These data can be divided into four categories:
Panorama data. Contains data such as people, cars, things, mobile phones, access control, WiFi, IoT perception, maps, addresses, house numbers, grids, population, houses, units, urban parts, etc. in the spatial dimension.
Full amount of data. On the basis of panoramic data, it includes time dimension, full-time and spatial data, including trajectory, activity, event and other data.
Global data. The association between data is built on panoramic data, which belongs to multi-dimensional association information, which is collected from multiple channels, multiple perspectives, and multiple sides. The model that contains all the information of the system, realizes the association, collision and multi-dimensional perception of data.
Holographic data. The global data and video images are merged to produce three-dimensional, multi-dimensional, and interconnected full-time and spatial data. Typical applications include 3D holographic projection, virtual display VR, and enhanced display AR.

The Industrial Revolution

The Industrial Revolution

There are four recognized industrial revolutions, and we are currently in the fourth industrial revolution. The seemingly unrelated fourth industrial revolution has truly affected the progress of video surveillance systems toward intelligence.

The first industrial revolution refers to the technological revolution initiated in Britain in the 1860s. It was a huge revolution in the history of technological development. It opened the era of replacing manual labor with machines. This is not only a technological reform, but also a profound social change. The first industrial revolution revolution started with the birth of working machines, marked by the widespread use of steam engines as power machines. This technological revolution and the related changes in social relations are called the first industrial revolution or industrial revolution. The first industrial revolution allowed the factory system to replace manual workshops and machines to replace manual labor: in terms of social relations, the Industrial Revolution eliminated the self-cultivating class attached to backward production methods, and the industrial bourgeoisie and industrial proletariat formed and grew. stand up.

The second industrial revolution refers to the completion of bourgeois revolutions or reforms in European countries, the United States, and Japan in the mid-nineteenth century, which promoted economic development. In the late 1860s, the second industrial revolution began. Mankind has entered the “Electrical Age”. The second industrial revolution greatly promoted the development of social productive forces and had a profound impact on the economy, politics, culture, military, science and technology, and productivity of human society. The socialization of capitalist production has been greatly strengthened, and monopoly organizations have emerged. The second industrial revolution made the capitalist countries uneven in their economic, cultural, political, military and other aspects. The imperialist struggles for market economy and world hegemony became more intense. The second industrial revolution promoted the formation of the world colonial system, and finally established the capitalist world system, and the world gradually became a whole.

The third industrial revolution is another major leap in the field of science and technology after the steam technology revolution and the power technology revolution in the history of human civilization. The third scientific and technological revolution is marked by the invention and application of atomic energy, electronic computers, space technology, and biological engineering. Information control technology revolution. The third scientific and technological revolution not only greatly promoted the transformation of human society, economy, politics, and culture, but also affected the way of life and thinking of mankind. With the continuous advancement of science and technology, Major changes have also taken place in all aspects of daily life. The third scientific and technological revolution aggravated the uneven development of capitalist countries and brought about new changes in the international status of capitalist countries. In the struggle of socialist countries against Western capitalist countries, the gap between the rich and the poor gradually widened. Promoted changes in social production relations worldwide.

The fourth industrial revolution is a new technological revolution. A new technological revolution based on artificial intelligence, clean energy, robotics, quantum information technology, virtual reality, augmented reality, and biotechnology. In fact, the fourth industrial revolution was also called Industry 4.0, which was first proposed by Germany. Opening the door to the future with artificial intelligence is exactly what this book will discuss in detail, especially its impact on video surveillance systems.

Video surveillance system development history

Video surveillance system development history

In 1951, some companies, mainly American Radio Corporation, began to develop video recorders and video tapes. In December 1953, the Pentax Roussby Institute took the lead in launching the color multi-track video tape and its playback system by using the multi-track method, but the broadcast picture was relatively blurry and could not be put into use immediately. In April 1956, the American Ampere Company took the lead in developing the world’s first practical commercial video tape recorder and named it “Ampere VRX-1000”.

In 1957, Panasonic developed the first electronic picture tube camera, and then introduced the 1-inch camera WV-010 in 1962, the three-color tube camera in 1970, the CCD color camera in 1985, and the WJ-FS50 video recorder in 1992. In 2001, the WJ-HD500 16-channel hard disk video recorder was launched. For nearly 40 years, Panasonic has been at the forefront of the security monitoring technology revolution, with super dynamic technology, automatic dark zone compensation technology, automatic rear focus adjustment technology, and lock tracking technology. , Intelligent analysis technology has led the development of the industry all the way. When it comes to video surveillance, there is another company that cannot be avoided that is Sony, and Sony’s core influence in the field of video surveillance comes from CCD.

In 1969, the Bell Telephone Research Institute in the United States invented the CCD. It is a magician who converts “light” information into “electric” information. In the Sony development team at that time, a young man named Yue Zhi Chengzhi was very interested in CCD and began his research on CCD. However, because this research is still far from commercialization, the more intelligent it becomes, the more it can only do research silently alone. In 1973, Iwama, the then-Vice President of Sony Corporation, a uniquely discerning operator discovered Ochi’s research and said with excitement: “This should be the subject of Sony’s semiconductor department! Okay, let’s do it. Cultivate this seedling!” At that time, Ochi only realized a rough “S” drawn with 64 pixels. However, Iwama put a puzzling sentence on Yue Zhi: “Use CCD to make a camera.” After that, the booming surveillance industry was born.

In November 1973, CCD finally set up a project in Sony, and established a development team centered on Yuezhi. In March 1978, Sony manufactured an integrated block that was considered “impossible” with 110,000 components on a circuit board, creating the world’s first CCD color camera. In 1985, the first 8mm camera “CCD-V8” was born. Afterwards, the development and launch of CCD were on track. Sony introduced HAD sensors in the early 1980s, ON-CHIP MICRO LENS in the late 1980s, SUPER HAD CCDs in the mid-1990s, NEW STRUCTURE CCDs in 1998, and EXVIEW HAD CCDs in 1999. CCD has also been widely used in the field of video surveillance.

CMOS image sensors and CCD image sensors appeared almost simultaneously in the 1960s. After 1990, the passive pixel CMOS image sensor entered the market as the first-generation CMOS image sensor, and then gradually became the mainstream sensor solution for cameras. This is something later.

In 1996, Axis launched the world’s first network camera. In 2008, Axis, together with Bosch and Sony, announced the establishment of ONVIF (Open Network Video Interface Forum), and jointly formulated open industry standards based on the principles of openness and openness, which promoted the development and popularization of network video surveillance systems. In October 2011, GoTV released the first video summary system; in May 2016, Jiadu Technology launched the “Video Cloud +” large application platform V1.0; in March 2018, Yuncong Technology officially released the high-performance AI camera “torch eye” smart face recognition camera.

When it comes to the development history of video surveillance, there are two other companies that have come from behind to mention, that is, China’s Hikvision and Dahua. According to the Nikkei (Chinese version: Nikkei Chinese website), the 2017 “Survey on Global Market Share of Major Goods and Services” was compiled. Among the 71 categories included in the survey, the products of Chinese companies have the largest market share in 9 categories. Among them, the number one camera, Hikvision, has a share of 31.3%, and the second number Dahua has a share of 11.8%. The two companies have a combined share of 43.1%, which means that almost half of the world’s cameras are owned by these two companies. made.

Hikvision was founded in 2001. In 2002, it released the DS-4000M video and audio compression card and DS-8000 network hard disk video recorder, which started Hikvision’s video surveillance journey. This journey lasted 16 years. After that, in 2003, the industry first implemented the H.264 algorithm on the DSP, and based on the H.264 algorithm, it was the first to launch the DS-4000H board with independent intellectual property rights and the network hard disk video recorder DS-8000M, opening a new era of H.264. In 2007, the first infrared barrel series camera was launched. With this camera, it successfully broke into the Chinese camera market and quickly became one of the mainstream infrared camera brands in the market, realizing the leap from DVR to camera. In 2009, the Public Security Industry Solutions Business Department was formally established, and the iVMS-8200 Safe City Comprehensive Application Management Platform product was released, successfully transforming from a product supplier to an overall solution provider. In 2012, the launch of the first civilian product-“Xiaoweishi” marked the beginning of the industry application of video surveillance to small and micro enterprises and home micro-video applications. In 2015, based on the concept of “Smart Security 2.0”, cross-border products represented by industrial cameras and drones were released to promote security from safety to efficiency to benefit. In 2017, Haikang released the AI ​​Cloud cloud edge integration strategy to march towards AI and promote the development of the industry.

Dahua Co., Ltd. was founded in 1993 and established a joint-stock company in 2001. In the early days, Dahua mainly produced hard disk video recorders. At that time, the DVR products on the market were all board-type, and all the core technologies depended on imports. Not only was the price high, ordinary consumers could not afford it, but also caused the long-term impact of national enterprises. suppress. In 2002, Dahua launched the industry’s first self-developed 8-channel audio and video synchronous embedded DVR, creating the first brand of embedded DVR, and making security begin to bloom everywhere. Since then, Dahua has continued to focus on video surveillance technology and has gradually grown to become the second largest company in the world in terms of camera market share. There are several important milestones in the development history of Dahua: Going overseas in 2003, launching the intelligent transportation all-in-one machine in 2007, becoming the de facto standard of China’s electronic police, focusing on image processing technology and network technology in 2008, and introducing CMOS in 2010 Technology and launched the high-definition high-power movement. In 2011, the concept of “cloud” was introduced. In 2012, HDCVI technology was adopted by the HDcctv alliance as the first international standard in China’s security industry. In 2014, the Le Orange brand was established, entered the civilian market, and established as the first in the United States. An overseas branch company, established an artificial intelligence research institute in 2016, and launched a cloud ecology and smart future strategy of “full intelligence, full computing, full perception, and full ecology”. It is expected that in the future, with video capabilities as the core and artificial intelligence as the backing, it will provide smart IoT solutions and operational services, and actively deploy smart video surveillance systems.

Intelligent video surveillance

Intelligent video surveillance

Surveillance system is called CCTV (Closed Circuit Television Surveillance System), which has slowly faded in the past 5 years, and has been gradually replaced by Video Surveillance System. With the advancement of technology, video surveillance systems have undergone significant changes. The first is the scale, ranging from dozens of cameras to hundreds, tens of thousands, and even millions of video networking applications, so there are Safe City, Skynet Project (from “Skynet recovery without leakage”), Xueliang Engineering (from “the eyes of the masses are discerning”) such a large-scale city-level video surveillance project; second is the degree of intelligence, from the initial surveillance to the motion detection alarm, then to the leftover alarm, cross-line alarm, and then to the near Two years of relatively hot face recognition, human body recognition, vehicle recognition, object feature recognition, etc.; finally, the application range of video surveillance is getting wider and wider. Video can be used for card-free parking lot access, access control, attendance, consumption, and even use In the intrusion alarm system.

The impact of artificial intelligence on video surveillance makes the system more intelligent, so it can be called an Intelligent Video Surveillance System (Intelligent Video Surveillance System). “GB/T 28181-2011 Security and protection video monitoring network system information transmission, exchange, control technical requirements” defines “Security and protection video monitoring network system (Security and protection video monitoring network system)” as “for the purpose of security precautions, Comprehensive application of video and audio monitoring, communication, computer network, system integration and other technologies, built in cities and large venues with information collection, transmission, control, display, storage, processing and other functions can realize the interconnection of different equipment and systems, An integrated network system with intercommunication and control.
“GB/T 50348-2018 Safety Protection Engineering Technical Specification” defines “Video Surveillance & Control System (VSCS, Video Surveillance & Control System)” as “electronics that uses video technology to detect and monitor fortified areas and display and record on-site images in real time. System and network.” From the definition of English, the control function has been added.

Broadly speaking, the intelligent video surveillance system also covers images (Image, for example, the bayonet system mainly uploads picture information), audio, so the intelligent video surveillance system can also be called the intelligent audio and video image surveillance system.

What is a CCTV system

What is a CCTV system

In the 1994 edition of the national standard “GB 50198 Civil CCTV System Engineering Technical Specifications”, CCTV system is defined as:
“Civilian CCTV system refers to the CCTV system used for anti-theft, disaster prevention, inquiry, visitor, monitoring, etc. in civil facilities. It is characterized by the transmission of image signals within a specific range by means of cables or optical cables to achieve long-distance surveillance. Purpose. The system format should be consistent with the general television format. Closed-circuit surveillance television should use a black and white television system; when color signals need to be observed, a color television system can be used. The system should be composed of four main parts: camera, transmission, display and control. When it is necessary to record the image of the surveillance target, a tape recording device should be installed. While monitoring the target, when the sound needs to be monitored, a sound transmission, monitoring and recording system can be configured.

In 2009, the author of this book gave a new definition:
“Closed-Circuit Television (CCTV) is one of the important components of the security system. It uses cameras to transmit audio and video signals to display, control and recording equipment through transmission lines. The front-end system and the local transmission system , Local display system, local control system, remote transmission system, and remote control system. The closed-circuit monitoring television system is different from the traditional radio and television system. The traditional radio and television system is one-point transmission and multi-point reception, which is an open The CCTV system (Opened), and the CCTV system is not publicly disseminated (Closed), one point is sent and many points are received (authorization is required), although some monitoring points provide public access services. CCTV systems are often used for security Demand for specific places, such as banks, casinos, entertainment venues, factories, communities, buildings, electricity, highways, airports, or military facilities. With the maturity of technology and the reduction of equipment costs, more and more places adopt surveillance System, such as the construction of a safe city.

The closed-circuit television monitoring system has three basic functions: monitoring, recording and playback. Surveillance mainly means that you can see the real-time pictures of the scene, video recording means recording the video images that can be monitored, and playback means playing the recorded video image data. The functions of image analysis, pre-warning, and post-event prevention can also be realized through more advanced technical means. After expansion, the CCTV system can have audio functions, which can monitor, record and playback audio signals. At the same time, the CCTV system has some intrusion alarm functions. Especially with the development of video analysis technology, to some extent, cameras can replace alarms. Probe.

In fact, after nearly 60 years of development, closed-circuit television monitoring systems have made revolutionary progress from analog systems to digitization, networking, and intelligence. With the influence of cloud computing and big data technology, coupled with the empowerment of artificial intelligence (AI, Artificial Intelligence) technology, the name, definition, and content of closed-circuit television monitoring systems can no longer adapt to the development of the new era, and more advanced systems are needed. , Namely the intelligent video surveillance system.