Beijing Haiyitai Technology Co., Ltd.

   Editor's Note: The author of this article, Shu Lifu, is a researcher at the Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, a leading expert in forest fire research, an expert in the expert group of the National Forest Fire Prevention Headquarters, and the deputy director of the Forest Fire Prevention Professional Committee of the China Forestry Society. He has presided over multiple forest fire prevention research projects, published 5 monographs, and authored 56 papers, with 7 papers indexed by SCI and 5 papers indexed by EI. As the deputy director of the National Technical Committee on Forest Fire Prevention Standardization, Shu Lifu participated in the standard development work of the "Technical Specifications for Forest Fire Prevention Video Surveillance System" compilation group. This article is his interpretation of some important contents of the "Technical Specifications for Forest Fire Prevention Video Surveillance System" and an expansion of his viewpoints. It proposes the utilization and application of the "standard" and forward-looking thinking on industry development. His insightful opinions provide a new perspective for readers to deeply understand the connotation of the "standard".

The "Technical Specifications for Forest Fire Prevention Video Surveillance System" (hereinafter referred to as the "Standard") was issued by the State Forestry Administration on January 18, 2016, and officially implemented on June 1, 2016, after two years of unremitting efforts by the National Technical Committee on Forest Fire Prevention Standardization, the preparation team, and related units. The Standard was proposed by the Office of the National Forest Fire Prevention Command and is under the jurisdiction of the National Technical Committee on Forest Fire Prevention Standardization (SAC/TC 523). The implementation of the "Standard" will have a profound impact on the informatization construction of forestry video surveillance for fire prevention nationwide.

Background: Uneven Equipment and Industry Standards in Need of ImprovementCurrently, the forest fire prevention video surveillance system software available in the market boasts diverse functions, but the hardware equipment varies greatly, lacking a unified design, production, and application standard. This has affected the uniformity and business applicability of the construction of forest fire prevention video surveillance systems nationwide, posing obstacles to the interconnection and interoperability of such systems in the future. Meanwhile, the introduction of new technologies such as high-definition video transmission and image recognition processing can effectively enhance the performance of forest fire prevention video surveillance systems. The establishment of industry standards will accelerate the diffusion of technological achievements and regulate market competition order.

Product development: Three stages towards maturity. The forest fire prevention video surveillance system has become one of the important means for forest fire prevention and monitoring in China. Its development has gone through three stages towards maturity.

Phase 1: Traditional urban security video surveillance products are used, and the command center adopts manual video inspection methods. This approach has a limited monitoring range, blurred images, and the system cannot perform identification and positioning. It relies entirely on manual inspection and only solves the problem of "seeing".

Phase 2: Based on the foundation established in Phase 1, the video surveillance system has enhanced the performance of the pan-tilt-zoom (PTZ) and incorporated a basic smoke and fire recognition algorithm, enabling preliminary location of fire points. However, the system still faces challenges such as poor recognition capabilities, lengthy patrol times, and significant errors in fire point localization. The equipment struggles to meet the fire prevention requirements in the harsh environment of forest areas, and while it is "usable," it is not "user-friendly.".

Stage 3: With the advancement of technology, video surveillance systems have also entered the era of intelligence. The new generation of front-end equipment incorporates high-precision spherical turntables and comprehensive intelligent smoke and fire recognition algorithms, reducing equipment patrol time and enhancing positioning accuracy and recognition capabilities. The system is capable of achieving "early detection, accurate alarming, and precise positioning" of fires. The forest fire prevention video surveillance system has entered a stage of "ease of use" and "effectiveness".

Currently, the quality of forest fire prevention video surveillance products varies, encompassing standards from three distinct stages. In light of this, the "Technical Specifications for Forest Fire Prevention Video Surveillance Systems" have been implemented, standardizing industry technical criteria and aligning with the goal of "preventing fires early, addressing small fires, and containing large fires" in forest fire prevention. This is of great significance for enhancing the informatization level of forest fire prevention. Simultaneously, it addresses the absence of technical standards for video surveillance systems in forest fire prevention applications, promoting the normalization and standardization of the construction of forest fire prevention video surveillance systems.

Indicator interpretation: Five indicators directly point to the key to fire prevention. Cruising cycle - the cruising cycle of the entire monitoring area is not more than 30 minutes

To detect forest fires as early as possible and buy time for fire suppression, research suggests that the maximum time for timely fire detection should not exceed 30 minutes. If the time spent on fire detection is too long, missing the optimal opportunity for suppression will result in greater losses to forest resources. From a technical implementation perspective, in forest fire prevention applications, taking a coverage radius of 15 kilometers as an example, equipment from individual manufacturers within the industry can complete effective identification within 20 minutes. Therefore, it is appropriate to define the "standard" cruise cycle as 30 minutes.

Fire detection rate - false alarm rate not exceeding 1%; false alarms per 10,000 hectares per day not exceeding 3

The primary function of the forest fire prevention video surveillance system is to trigger an alarm after accurately and effectively identifying smoke and fire. The identification capability indicators should meet the following requirements: when the contrast ratio is greater than or equal to 10%, the minimum visible light identification capability indicator for smoke and fire should not exceed 10×10 pixels, and the minimum infrared thermal imaging identification capability indicator for smoke and fire should not exceed 2×2 pixels.

Currently, the development of intelligent recognition technology has not yet achieved "perfection". There may be instances of missed and false alarms during fire detection. To balance the current technical level and meet the needs of forest fire prevention operations, the "standard" requires that the missed alarm rate of the system must not exceed 1%. The false alarm rate of the system must be acceptable to the personnel on duty, with a maximum of 3 false alarms per 10,000 hectares per day.

Positioning accuracy - positioning error not exceeding 100 meters

In the process of forest fire suppression, especially when the fire occurs in a large forest area, accurately determining the location of the fire point will directly affect whether the command and suppression personnel can choose the correct suppression path, reasonably allocate surrounding suppression resources, and grasp the optimal suppression time. In principle, the requirement for the accuracy of fire point positioning is that the error should be as small as possible. However, due to limitations imposed by major factors such as equipment production and processing, engineering installation, and GIS errors, the "standard" specifies an indicator of positioning accuracy better than 100 meters. This not only takes into account the actual application effect but also considers the difficulties of equipment production, implementation, and system construction costs.

Visible light and infrared - The system should have the ability to automatically recognize visible light smoke and fire; the system should have the ability to automatically recognize infrared smoke and fire

Currently, forest fire prevention video surveillance systems predominantly utilize a dual-lens monitoring approach, incorporating both visible light and uncooled infrared technologies. This integration is relatively scientific, primarily due to the distinct characteristics of the two methods. The visible light system boasts clear images, high resolution, and low cost, closely aligning with human visual perception. During the day, it offers long-range monitoring and is highly sensitive to smoke, enabling early detection of fires through smoke recognition. However, in dense fog or at night, it becomes challenging to identify smoke from a distance. Under high-illumination weather conditions, distinguishing between strong light and firelight becomes difficult. The uncooled infrared thermal imager is sensitive to visible heat sources and excels in penetrating fog compared to visible light, offering superior fire detection capabilities at night. However, it lacks sensitivity to smoke recognition, operates within a shorter monitoring range, and faces challenges in detecting fires under non-line-of-sight conditions, day or night.

To ensure that the forest fire prevention video surveillance system can perform round-the-clock forest fire prevention monitoring and early warning, the system should be equipped with a combination of visible light and infrared thermal imaging devices. This allows for round-the-clock cross-confirmation and identification of smoke and fire. Currently, some equipment manufacturers have achieved this, and they also possess capabilities such as pre-processing recognition algorithms and multispectral fusion recognition.

Front-end monitoring equipment protection safety - overall protection level not less than IP66; lens and camera protection chamber protection level not less than IP67

The natural environment in the forest area is harsh and complex, often subject to rain, snow, sandstorms, and other incursions. This requires that the overall protection level of front-end monitoring equipment must reach IP66 to fully prevent dust, rainwater, and other substances from infiltrating the equipment, thus ensuring its normal operation. Lenses and cameras are important components of the system for video capture. According to the "standard", the protection level of the protective cabin must reach IP67 to eliminate condensation on the visible light window caused by temperature changes. At the same time, it can effectively protect the working environment of the lenses and cameras, extending their service life.

The above indicators, including fire detection rate, equipment accuracy, cruise cycle, and optical imaging, are crucial and mutually restrictive. When the system is operating, even the best recognition algorithm cannot demonstrate its recognition ability without the combination of good equipment accuracy and a good optical imaging system as a foundation, making it difficult to support early and accurate detection of fires. Without algorithms with multi-dimensional fusion recognition capabilities, even the best hardware equipment cannot ensure that the cruise cycle meets the requirements, making it impossible to accurately locate the fire point. Therefore, production enterprises and fire prevention departments should comprehensively consider these key factors when designing and using the system.

Construction Guarantee to Ensure Investment Efficiency and Safe OperationGiven the vast forest areas in our country, most of which are located in uninhabited regions and lack communication and power supply systems, the investment in transmission and power supply systems, as well as engineering infrastructure, accounts for a significantly high proportion in the construction of forest fire prevention video surveillance systems. On the premise of fully ensuring the monitoring coverage, prioritizing the use of large-radius video surveillance equipment will reduce construction investment costs and subsequent operation and maintenance costs. At the same time, it enables the application of wireless communication equipment, drone relay equipment, small meteorological equipment, and other devices, enhancing the operational safety and intelligence level of monitoring stations, thereby improving the overall operational efficiency of the system.

Development Trends: Enhancing Technical Capabilities to Showcase Better Prospects. As the "Technical Specifications for Forest Fire Prevention Video Surveillance Systems" is being implemented for the first time, the "standard" has taken into account the current practical level to accommodate more manufacturing enterprises to achieve compliance. However, it is foreseeable that as the industry development level improves and the pace of modernization in forest fire prevention accelerates, the standard will continue to evolve with the situation. Therefore, here we specifically introduce some products and technologies that are currently at the forefront of domestic industry development for sharing with everyone.

Spherical Turntable: The working environment of front-end equipment for forest fire prevention video surveillance systems is similar to that of border and coastal defense systems. The monitoring technology requirements for border and coastal defense systems stipulate that when the application involves a monitoring radius of more than 3 kilometers, the positioning accuracy and wind resistance requirements for identifying targets such as vehicles and people must be met. It is recommended to use spherical turntable equipment. This is because the wind load factor of the spherical structure is basically equal in any direction, and it is minimally affected by wind forces from all directions. Compared to the commonly used gimbal structure, the spherical turntable has stronger wind resistance under the same wind environment. At the same time, the spherical turntable adopts a high-precision servo control system, which has faster rotation speed and higher positioning accuracy compared to the gimbal. Therefore, it is recommended that the design concept of military products be referenced for front-end equipment for forest fire prevention video surveillance to enhance the overall technical application capability.

Algorithm prepositioning: The integration of intelligent image recognition algorithms with high-precision spherical turntables is crucial for ensuring accurate fire detection and precise positioning. The front-end equipment employs embedded recognition algorithms. During the operation of the recognition algorithm, the system can greatly enhance its recognition capability as the image does not need to be compressed and transmitted, maintaining its quality without loss. Even in situations where bandwidth is limited or network transmission is interrupted, it can still operate normally locally and monitor fire conditions, while storing fire alarm information at the front end. Additionally, the equipment adopts an embedded hardware design, simplifying the hardware system for fire detection, making the structure more compact and more stable. Due to the high demand for manufacturers' R&D technical capabilities in front-end embedded algorithm design, only a very small number of manufacturers in the industry have achieved breakthroughs in this skill. Looking at technological development, algorithm prepositioning is the key to solving the accuracy of smoke and fire detection, and it is also the necessary path for the intelligent evolution of forest fire prevention video surveillance.

Standardized design: Currently, the construction of forest fire prevention video surveillance across the country is primarily centered at the grassroots level, without achieving multi-level system networking from county to city and city to province. The standardized, open, and compatible design of front-end hardware is the prerequisite for achieving video surveillance system networking and the fundamental guarantee for unified command and dispatch in forest fire prevention.

Standardization is a crucial tool for advancing the modernization of national governance. The implementation of standards such as the "Technical Specifications for Forest Fire Prevention Video Surveillance Systems" has injected a "new breeze" into the modernization of China's forest fire prevention efforts. We wish for the introduction of more standards in the forestry sector, in order to expedite the modernization of forestry construction and development.