HD standard in CCTV.

The term HD (hi definition) video, that is, high-definition video, came to CCTV from the field of television and multimedia. At the beginning of the new century, the rapid development of liquid crystal and plasma display technologies — the ability to create inexpensive screens with a large diagonal — made it possible to appreciate the advantages of high-resolution images. Digital high-definition television formats have replaced the analog format.

Today, when buying a modern TV, we pay attention to the label with the inscription HD ready and the supported digital image standard: 720p, 1080i, etc., characterizing the image resolution.
The most common HD video standards today are:
720 p (1280 x 720 pc, image aspect ratio 16:9, progressive scan);
1080 p (1920 x 1080 pc, image aspect ratio 16:9, progressive scan).
In many Western European countries, high-definition television has long been commonplace. Television tuners have been developed to receive high-definition signals, digital interfaces (HDMI, DVI-D) for monitors that provide uncompressed digital signal transmission, and formats for information carriers (Blue Ray, HD DVD).
The Russian government plans that by 2015 television in our country will also switch to the HDTV standard.
Of course, the processes taking place in broadcast television, digital photo and video technology could not bypass applied television, which is CCTV. The possibility of transition to digital standards of high-definition video images opens up new possibilities for security video surveillance systems.
First of all, it is necessary to note the possibility of obtaining a highly detailed image with the possibility of subsequent scaling. Digital processing of megapixel images allows analyzing individual areas of the frame: for example, recognizing a car number or the face of an offender.

The second important advantage of the transition of CCTV to digital high-definition standards was the achievement of a balance between the resolution of the video image formed by the camera and the resolution of the monitor. The era of monitors with a cathode-ray tube has gone forever, but the analog video signal standard remains. Outputting an image of an analog standard to the screen of an LCD or plasma monitor is accompanied by a deterioration in the contrast and brightness of the image, and the color suffers. The need to use powerful image processors in monitors to compensate for artifacts unreasonably increases the cost of video panels. The resolution of megapixel cameras corresponds to the resolution of modern monitors and guarantees a high degree of image reliability and visual comfort for the operator.
Finally, a number of megapixel camera manufacturers implement the idea of ​​replacing several analog cameras installed side by side with one high-resolution digital camera in their products. There is some truth in this. Small objects – cafes, gas stations, small shops – can be equipped with one or two megapixel cameras with a specialized wide-angle lens. In conditions of a limited observation area, they can replace 3-4 analog standard TV cameras.
It should be noted that the penetration of high-definition video technologies into the CCTV field was associated with the need to solve a number of technical problems.
The most fundamental task was the need to select an image transmission interface. Unlike high-definition television, where satellite data transmission channels or optical cables are widely used, CCTV required a less expensive, more universal interface that would provide quick and easy system scaling. This interface was an information computing network based on the TCP/IP protocol stack. Indeed, an IP network is best suited for creating a high-definition video surveillance system. Data is transmitted digitally, which means we are not bound by any analog standard. The topology of an IP network can be so diverse and complex that scaling the system is not difficult. However, there are still difficulties, and until recently they were difficult to resolve.Having adopted HDTV standards (720 p, 1080 p), high-definition video surveillance systems faced the need to find an optimal image compression algorithm. The M-JPEG algorithm used for IP cameras with an analog resolution of 768 x 576 px is not optimal for HD IP cameras, since the data flow from a megapixel camera can be up to 30–40 Mbit (a camera with a resolution of 3 MP). Thus, to create a high-definition IP video system, it is necessary to use expensive gigabit network technologies. No less relevant for security systems is the issue of recording images to disk. Large amounts of information require serious expenses to create a long-term archive. Of course, there are more effective compression algorithms — MPEG4, H.264, but the implementation of these algorithms for megapixel cameras required the use of powerful and expensive processors. As a result, HD CCTV remained a beautiful dream and megapixel cameras were used mainly in applied tasks.
No less acute was the problem of a shortage of specialized lenses that provide the necessary resolution for megapixel video cameras. The market only had expensive optics for megapixel machine vision cameras with a format uncharacteristic for CCTV.
Technologies are developing. 2008 was a turning point for high-definition IP video surveillance systems. Almost all manufacturers of megapixel IP cameras for CCTV updated the range of solutions they offer. The efficient H.264 High Profile compression algorithm, capable of compressing a 2 MP camera video stream to 4 Mbit/s, is present in new models no longer as an alternative codec, but as the main one, having finally displaced M-JPEG. The computing power of universal processors made it possible to create workstations for decoding and visualizing several HD streams simultaneously. The software for HD video systems allows for efficient image analysis in different areas of the frame, creating separate “zones of interest” for the operator. Finally, all manufacturers of CCTV optics have launched the production of “megapixel” lenses, optimizing their cost.
Undoubtedly, this is a breakthrough and a new stage in the development of CCTV, as a fundamentally new level of quality has been reached. If until recently opponents of IP video surveillance systems objectively recognized only one advantage of a digital system – distribution, now the objectively high image quality is indisputable.
In fact, the thesis that the quality of a video system is determined by the quality of the weakest element of the system is becoming a thing of the past. Digital HD cameras are capable of generating high-quality high-resolution images, transmitting digital networks, and displaying images without loss of quality on monitors. And although not all issues have been resolved yet and the cost of an HD video system remains high compared to an analog quality system, no one has any doubts about the future of HD CCTV.