The construction of a safe city began as a pilot project in four cities in Xuanwu District in Beijing, Jinan in Shandong, Hangzhou in Zhejiang, and Suzhou in Jiangsu. In June 2004, the Ministry of Public Security and the Ministry of Science and Technology initiated the establishment of the first batch of science and technology strong police demonstration cities in 21 cities including Beijing and Shanghai in order to comprehensively advance the implementation of the science and technology strengthening police strategy. In August 2005, the Ministry of Public Security further proposed the construction of a “3111 pilot project†to select the 22 provinces to carry out pilot projects for the construction of alarm and monitoring systems at the provincial, city, and county levels. Today, the construction of safe cities is still in full swing.
The various systems such as the alarm and monitoring in the Safe City project are naturally inseparable from modern digital electronic technology. Modern digital electronic technology is an important means and technical support for improving the level of urban public safety management. With the application of information technology in various subsystems of urban alarm and monitoring systems, the development and application of digital electronic technology and multi-technology integration has become a new type. The Inevitable Trend of Intelligent City Public Safety Management. Due to the differences in economic and social environment, various modes have been adopted for the construction of city surveillance and warning systems in different regions. However, a large number of mature digital technologies have been used throughout the country to build systems. These include:
First, video surveillance technology Video surveillance is an important part of the security system, it is a comprehensive system with strong prevention capabilities. Video surveillance is widely used in many occasions for its intuitive, accurate, timely and rich information content.
1. Fixed Video Surveillance Technology In the construction of urban surveillance and alarm systems, the fixed front-end video surveillance technology is the most widely used. Common fixed video surveillance solutions can be divided into two categories: First, all-digital solutions, video signals directly converted to digital signals after the acquisition, transmission and storage processes are all digital. All-digital solution wiring is simple, but there will be data loss during information data compression and transmission. At the same time, high network transmission requirements and unstable network conditions occur. The second is the combination of digital simulation. The front end of this solution uses an analog camera to save and transmit images through a hard disk video recorder. It can directly restore analog video from a hard disk video recorder. Signal output, but also through the network PC to restore the video signal output.
2, mobile video surveillance technology in the city monitoring and alarm system construction no matter how high the video monitoring point coverage, there will always be the existence of monitoring blind spots, especially if there will always be links or power can not be solved, then Mobile video surveillance has become an indispensable and important part of urban surveillance and alarm systems. At present, the transmission of mobile video surveillance is mainly divided into the public satellites, or relying on 3G networks, but can be used to convert the received signals into analog images and then use digital encoding to join the backbone network of urban monitoring and alarm systems. Go to.
With the increase of mobile wireless network bandwidth, the imminent deployment of 3G mobile communication systems and the continuous enhancement of mobile terminal information processing capabilities, mobile video surveillance systems born out of traditional network video surveillance technologies have become a hot spot in the current surveillance field. Compared with professional and mysterious surveillance products, if mobile phones can be used to achieve mobile video surveillance, it is possible to make professional video surveillance more widely used, thus pushing network video surveillance to a new height of mobile video surveillance. .
Second, electronic alarm technology Electronic alarm technology refers to the electronic technology that can send an alarm signal in the event of a dangerous situation. In the event of an emergency, it is possible to accurately display the location of the incident in the security control center through the sound and light alarm signal, so that emergency measures can be taken promptly. According to the different state of the defense target, it can be divided into fixed target alarm technology and mobile target alarm technology:
1. Fixed target alarm technology The fixed target alarm system is mainly composed of alarms, detectors, sensors, channels, and alarm controllers. The fixed target alarm technology is that the detector transmits the detected electrical signal through the channel to the alarm control center in the duty room. After an alarm occurs in the alarm system, security guards can promptly take necessary measures to deal with emergencies and effectively stop illegal intrusions and damages according to the situation.
2. Mobile target alarm technology The mobile target alarm technology is a kind of protection technology that is specially used to guarantee the safety of important and precious mobile objects. It comprehensively uses alarm technology, positioning technology, wireless communication technology, GIS geographic information technology and computer technology, and can be networked with public security 110, emergency 120, and traffic accident 122 to realize a wide range of mobile body security services. The mobile target alarm technology is currently mainly used for the prevention of important and valuable vehicles (or ships) such as bank transport vehicles.
Third, video image recognition technology Video image recognition as the name suggests is based on the acquisition of video images to obtain relevant information technology. At present, in the Safe City project, it is mainly embodied in vehicle brand identification technology and behavior identification technology.
1. Vehicle number plate identification technology The vehicle number plate identification system has the functions of automatically capturing and identifying license plates of vehicles passing through pre-set areas, and automatically comparing them with the database of suspected “blacklist†databases, alarms and video tracking. For accurate, stable and all-weather detection and recording of vehicle information on the road, public security organs can quickly dispatch, control and handle corresponding alarm situations through the system's alarm platform, enabling timely deployment and rapid response of technical functions.
License plate recognition technology is based on digital image processing, pattern recognition, computer vision and other technologies, and analyzes the images or video sequences of the vehicles captured by the camera to obtain the unique license plate number of each car, thereby completing the recognition process. Through some follow-up processing means, it is possible to realize the functions of parking lot charging management, traffic flow control index measurement, vehicle positioning, car theft prevention, and super-speed super-speed supervision. For the maintenance of traffic safety, urban security, and prevention of traffic jams, the realization of automated traffic management has practical significance.
The system collects the video image captured by the camera including the license plate through the video capture interface, and then processes the dynamically acquired image to overcome the image interference, improves the recognition effect, and then automatically finds the position of the license plate in the dynamically acquired image, that is, the edge detection. , And divides out the rectangular area of ​​the single character, then carries on the binarization to the license plate, finally recognizes the regular character input character recognition system.
2. Behavior Recognition Technology Behavior recognition technology, especially face recognition technology, has been researched since the early 1980s and has now achieved breakthroughs. Face recognition refers to the biometric identification technology that uses identity analysis to compare facial features. The main technologies include face image collection, face location, face recognition preprocessing, identity verification, and identity search.
The problem of face recognition due to different light sources, different viewing angles, and the influence of the natural environment on the recognition rate has not been well resolved. The face recognition system using infrared illumination has made some progress and is not widely used in the construction of alarm and monitoring systems in various cities. There is still much work to be done in the wide application of this technology.
The various systems such as the alarm and monitoring in the Safe City project are naturally inseparable from modern digital electronic technology. Modern digital electronic technology is an important means and technical support for improving the level of urban public safety management. With the application of information technology in various subsystems of urban alarm and monitoring systems, the development and application of digital electronic technology and multi-technology integration has become a new type. The Inevitable Trend of Intelligent City Public Safety Management. Due to the differences in economic and social environment, various modes have been adopted for the construction of city surveillance and warning systems in different regions. However, a large number of mature digital technologies have been used throughout the country to build systems. These include:
First, video surveillance technology Video surveillance is an important part of the security system, it is a comprehensive system with strong prevention capabilities. Video surveillance is widely used in many occasions for its intuitive, accurate, timely and rich information content.
1. Fixed Video Surveillance Technology In the construction of urban surveillance and alarm systems, the fixed front-end video surveillance technology is the most widely used. Common fixed video surveillance solutions can be divided into two categories: First, all-digital solutions, video signals directly converted to digital signals after the acquisition, transmission and storage processes are all digital. All-digital solution wiring is simple, but there will be data loss during information data compression and transmission. At the same time, high network transmission requirements and unstable network conditions occur. The second is the combination of digital simulation. The front end of this solution uses an analog camera to save and transmit images through a hard disk video recorder. It can directly restore analog video from a hard disk video recorder. Signal output, but also through the network PC to restore the video signal output.
2, mobile video surveillance technology in the city monitoring and alarm system construction no matter how high the video monitoring point coverage, there will always be the existence of monitoring blind spots, especially if there will always be links or power can not be solved, then Mobile video surveillance has become an indispensable and important part of urban surveillance and alarm systems. At present, the transmission of mobile video surveillance is mainly divided into the public satellites, or relying on 3G networks, but can be used to convert the received signals into analog images and then use digital encoding to join the backbone network of urban monitoring and alarm systems. Go to.
With the increase of mobile wireless network bandwidth, the imminent deployment of 3G mobile communication systems and the continuous enhancement of mobile terminal information processing capabilities, mobile video surveillance systems born out of traditional network video surveillance technologies have become a hot spot in the current surveillance field. Compared with professional and mysterious surveillance products, if mobile phones can be used to achieve mobile video surveillance, it is possible to make professional video surveillance more widely used, thus pushing network video surveillance to a new height of mobile video surveillance. .
Second, electronic alarm technology Electronic alarm technology refers to the electronic technology that can send an alarm signal in the event of a dangerous situation. In the event of an emergency, it is possible to accurately display the location of the incident in the security control center through the sound and light alarm signal, so that emergency measures can be taken promptly. According to the different state of the defense target, it can be divided into fixed target alarm technology and mobile target alarm technology:
1. Fixed target alarm technology The fixed target alarm system is mainly composed of alarms, detectors, sensors, channels, and alarm controllers. The fixed target alarm technology is that the detector transmits the detected electrical signal through the channel to the alarm control center in the duty room. After an alarm occurs in the alarm system, security guards can promptly take necessary measures to deal with emergencies and effectively stop illegal intrusions and damages according to the situation.
2. Mobile target alarm technology The mobile target alarm technology is a kind of protection technology that is specially used to guarantee the safety of important and precious mobile objects. It comprehensively uses alarm technology, positioning technology, wireless communication technology, GIS geographic information technology and computer technology, and can be networked with public security 110, emergency 120, and traffic accident 122 to realize a wide range of mobile body security services. The mobile target alarm technology is currently mainly used for the prevention of important and valuable vehicles (or ships) such as bank transport vehicles.
Third, video image recognition technology Video image recognition as the name suggests is based on the acquisition of video images to obtain relevant information technology. At present, in the Safe City project, it is mainly embodied in vehicle brand identification technology and behavior identification technology.
1. Vehicle number plate identification technology The vehicle number plate identification system has the functions of automatically capturing and identifying license plates of vehicles passing through pre-set areas, and automatically comparing them with the database of suspected “blacklist†databases, alarms and video tracking. For accurate, stable and all-weather detection and recording of vehicle information on the road, public security organs can quickly dispatch, control and handle corresponding alarm situations through the system's alarm platform, enabling timely deployment and rapid response of technical functions.
License plate recognition technology is based on digital image processing, pattern recognition, computer vision and other technologies, and analyzes the images or video sequences of the vehicles captured by the camera to obtain the unique license plate number of each car, thereby completing the recognition process. Through some follow-up processing means, it is possible to realize the functions of parking lot charging management, traffic flow control index measurement, vehicle positioning, car theft prevention, and super-speed super-speed supervision. For the maintenance of traffic safety, urban security, and prevention of traffic jams, the realization of automated traffic management has practical significance.
The system collects the video image captured by the camera including the license plate through the video capture interface, and then processes the dynamically acquired image to overcome the image interference, improves the recognition effect, and then automatically finds the position of the license plate in the dynamically acquired image, that is, the edge detection. , And divides out the rectangular area of ​​the single character, then carries on the binarization to the license plate, finally recognizes the regular character input character recognition system.
2. Behavior Recognition Technology Behavior recognition technology, especially face recognition technology, has been researched since the early 1980s and has now achieved breakthroughs. Face recognition refers to the biometric identification technology that uses identity analysis to compare facial features. The main technologies include face image collection, face location, face recognition preprocessing, identity verification, and identity search.
The problem of face recognition due to different light sources, different viewing angles, and the influence of the natural environment on the recognition rate has not been well resolved. The face recognition system using infrared illumination has made some progress and is not widely used in the construction of alarm and monitoring systems in various cities. There is still much work to be done in the wide application of this technology.
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