Analysis: What is missing from video surveillance in the digital high-definition era?

The concept of high-definition digital video surveillance has been recognized by more and more users and manufacturers. The ultra-high image quality and ultra-wide scenes brought by high definition give people a great visual shock. The clarity of high-definition network cameras can be said to be in a stage of rapid improvement. From megapixels to 2 million, then to 3 million, 5 million, etc., corresponding products have appeared on the market. With the increasing maturity of high-definition camera technology, video conferencing, factory monitoring and community security are inseparable from its presence. Digital monitoring is gradually replacing analog monitoring, standard definition is gradually moving towards high definition, and the application of monitoring technology is constantly expanding.

    Digital surveillance application expansion

    Since digital video surveillance conforms to the development trend of digitization, networking and intelligence in the current information society, digital wireless video surveillance is gradually replacing analog surveillance and is widely used in all walks of life.

    Easy to process by computer: Since the video images are digitized, the computer's fast processing capabilities can be fully utilized to compress, analyze, store and display them. Through video analysis, abnormal situations can be discovered in time and linked to alarms, thus achieving unattended operation.

    Suitable for long-distance transmission: Digital information has strong anti-interference ability, is not easily affected by the attenuation of transmission line signals, and can be encrypted for transmission, so it can monitor the scene in real time thousands of kilometers away. Especially when the scene environment is harsh or it is inconvenient to go deep into the scene directly, digital video monitoring can achieve the effect of being on the scene in person. Even if the scene is destroyed, the real record of the scene can still be obtained from a distance.

    Easy to search: In traditional analog monitoring systems, when a problem occurs, it takes a lot of time to watch the videotape to find the on-site records; in digital video monitoring systems, using the index established by the computer, the corresponding on-site records can be found within a few minutes.

    Improved image quality and monitoring efficiency: The computer can be used to remove noise and sharpen unclear images. By adjusting the image size and taking advantage of the high resolution of the display, clear high-quality images can be viewed. In addition, 16 or even 32 video images can be viewed simultaneously on one display.

    The system is easy to manage and maintain: The digital video surveillance system is mainly composed of electronic equipment with high integration, and wireless video transmission can utilize wired or wireless channels. In this way, the entire system is modular in structure, small in size, and easy to install, use and maintain.

    Digital surveillance development requirements

    Digital wireless video surveillance system not only conforms to the future development trend of the information industry, but also represents the future development direction of the surveillance industry. It contains huge business opportunities and economic benefits, and has become a digital product that has attracted much attention in the current information industry. Especially in recent years, with the advancement of technology and the continuous development of social economy, higher requirements have been put forward for the accuracy, effectiveness and convenience of the surveillance system. Specifically, it is mainly reflected in the following two aspects:

    First, the scope of video surveillance needs to be wider, from traditional security monitoring to management monitoring and production and operation monitoring, and higher requirements are also put forward for the coverage and implementation distance of the same system. In layman's terms, it is necessary to achieve more points and wider coverage.

    Secondly, it requires the monitoring system to be integrated with the management information system and network system to realize the compressed storage, transmission and automatic processing of large amounts of video data, thereby achieving resource sharing and providing convenient, fast and effective services for managers and decision makers at all levels.

    High-definition monitoring advantages

    In the case of high-definition surveillance, CMOS has a faster response speed than CCD and is more suitable for the large amount of data in high-definition surveillance. At the same time, CMOS has an unparalleled price advantage. Therefore, more and more high-definition surveillance manufacturers are choosing CMOS as the first choice for high-definition camera sensors. It can be predicted that the future high-definition camera market will be the market for CMOS cameras.

    For video surveillance, image clarity is undoubtedly the most critical technical indicator. The clearer the image, the more obvious the details, and the better the recognition effect. Its monitoring advantages mainly include the following aspects:

    1. Provide high-resolution images, obtain more video information, and realize intelligent analysis

    The improvement of the resolution of high-definition network cameras has made video-based intelligent analysis easier to implement. The rich information brought by high definition has greatly reduced the false alarms caused by the unclear images of traditional analog cameras, and also laid the most basic data foundation for high-level intelligent analysis. At present, common intelligent analysis functions include video occlusion detection, motion detection, abandoned object detection, vehicle reversal, illegal intrusion, population statistics, etc. These intelligent analysis functions have been widely used in many fields. The wide application of intelligent analysis functions has increased the demand for network high-definition cameras and brought more confidence to the popularization of network high-definition cameras.

    2. Video coverage is wider

    Under the condition that the monitoring coverage area is the same, one megapixel network camera can replace the original 2 or 3 standard definition cameras, or even more. For wide-angle and large-scale monitoring intensive places, such as airports, transportation, checkpoints, banks, perimeters, etc., only a small number of megapixel network cameras are needed to achieve the previous effect.

    3. Support higher frame rate and high image fluency

    Both 720p and 1080i/1080p can support 60 frames per second, and the image fluency is twice as high as that of standard definition. Support large-screen display and 16:9 widescreen display, which can greatly enhance the user's viewing experience.

    4. High-definition image quality provides favorable conditions for intelligent monitoring

    High-definition monitoring can provide high-definition images with more content and more details, thus creating conditions for the application of intelligent monitoring, providing more clear information for dangerous places, and improving safety assurance.

    High-definition surveillance technology development

    1. Improvement of resolution

    At present, analog cameras have reached their limit in terms of clarity, and it is difficult to have a major breakthrough in a short period of time. However, high-definition network cameras are still in a stage of rapid improvement in all aspects, whether it is full-time 720P or 1080P resolution cameras, from the traditional standard definition D1 resolution (ie 720×576 pixels) to 1080P resolution (1920×1080 pixels), the amount of picture information has increased by about 5 times, and the number of clarity lines has more than doubled.

    2. Improvement of coding efficiency

    As we all know, H.264 currently supports three main encoding methods, namely Highprofile, Mainprofile, and Baselineprofile, with encoding efficiency decreasing in turn. Under the same image quality, the bandwidth occupied by the video encoded by the Highprofile method is only 50% of that of the Baselineprofile. The reduction in bandwidth will bring about a series of reductions in the cost of building a security system. For example, when storing a 4M bit rate, 43.2G of space is required for one day, while a 2M bit rate only requires 21.6G of space, reducing the storage cost by half.

    3. Standardization of transmission protocols

    There are many domestic security brands, and the protocols used by high-definition network cameras are not unified. It is difficult for network monitoring equipment from different manufacturers to coexist in the same monitoring system. With the popularization of high-definition network cameras, standard network transmission protocols have been recognized by more and more manufacturers, and both ONVIF and PSIA have more and more followers. The popularization of standard network transmission protocols has gradually made it possible for monitoring systems from various manufacturers to be freely networked.

In the next few years, the adoption of standardized network transmission protocols will become the pass for high-definition network cameras to enter the market.

    4. High-performance image sensor

    Photosensitive devices play a pivotal role in the image quality of explosion-proof cameras. Currently, there are two main sensors on the market: CMOS and CCD. Compared with the two sensors, CMOS has excellent wide dynamic performance, which can reach more than 100db, while the dynamic range of common CCD is basically around 60db; with the development of CMOS technology, professional million-level monitoring dedicated CMOS sensors now also have higher sensitivity, which can meet most applications in terms of image brightness and low-light effects. Under normal light, the effect of CMOS is basically the same as that of CCD, and even exceeds the image quality of low-end and mid-end CCDs. However, because CCD has an independent DSP, CMOS cannot achieve the effect of high-end CCDs in the short term.