| Video surveillance system is the main method of city safety management and key area monitoring,and it is widely used in safe cities,military security and other fields.Due to the limitation of the camera's viewing angle,the video surveillance system can only monitor a certain angle at the same time,which cannot meet the requirements of full coverage and no blind spots for intelligent monitoring.The radar-guided video surveillance system can meet this demand,but the application scenario requires high security for video storage and transmission,and the continuous change of viewing angle results in a large amount of video data.Traditional video stream encryption technology cannot meet the needs of real-time video stream encryption.This article focuses on the coordination of multiple monitoring methods of the video surveillance system and the safe and efficient real-time video encryption technology,and proposes radar-guided video surveillance and a real-time video encryption scheme for continuously changing viewing angles.In the aspect of radar-guided video surveillance,a radar-guided video surveillance method is proposed to solve the problems of narrow video surveillance area and many blind spots to realize the integration of radar target discovery and video surveillance systems.According to the real-time feedback of the target position information from the radar,the azimuth angle,the pitch angle and the zoom factor relative to the camera are calculated,and the moving target is tracked through pan-tilt rotation and lens zoom,realizing real-time coordinated monitoring of the target.Aiming at the problem that the delay caused by "radar feedback first,camera control later" causes the camera to rotate lag and the target is lost in the picture,a radar-guided single target automatic fast tracking algorithm is proposed.According to the target information and delay time fed back by the radar,the problem is predicted The next location information of the target guides the camera to track and monitor.Experiments show that compared to the camera directly tracking the target information fed back by the radar,the matching accuracy of the camera center and the target is improved by 14.6%.Aiming at multiple target tracking scenarios,a radar-guided multi-target automatic tracking algorithm is proposed,and the monitoring warning area is defined.The speed,acceleration and distance between each target approaching the warning area and other attributes are comprehensively considered for weighting.Process to assess the degree of danger of each target relative to the warning area,adjust the azimuth angle and pitch angle of the camera to focus on monitoring the set of targets with the most dangerous degree.Experiments have shown that compared to the multi-target screening of a dangerous target for tracking,the monitoring failure rate is reduced by 80.1%.In terms of real-time video encryption with continuously changing viewing angles,the traditional selective encryption method based on H.264 encoding only selects the syntax element encryption of a single encoding stage in the video encoding process.There are few syntax elements in a single stage,and the protection of sensitive video information is weak.There is a problem of reconstruction of sensitive video information.In response to this problem,a multi-stage selective encryption method based on H.264 encoding is proposed.In the encoding process,the cipherability of the three encoding stages of intra prediction,transform encoding,and CAVLC is analyzed,and the video image reconstruction is filtered out.Encrypt multiple syntax elements that have large impact and small impact on video compression efficiency.Experiments show that compared with the single-stage selective encryption method,the quality evaluation parameters PSNR and SSIM of encrypted video using this method are reduced by 5.1% and 43.3% on average,respectively,which improves the security of video perception.In order to solve the problem that the high-dimensional chaotic mapping system generates a key sequence slowly,which leads to the low efficiency of the syntax element encryption in video encryption,a method of generating a key sequence by double PWLCM chaotic mapping is proposed.The first PWLCM generated key sequence is judged by the method.Whether the selected syntax element is encrypted,the second PWLCM generated key sequence encrypts the syntax element.Experiments show that compared with the high-dimensional chaotic mapping system,this method has a 66.7%increase in the key sequence generation speed and a 36.8% reduction in the encryption delay ratio,which is suitable for real-time application scenarios where the viewing angle is continuously changing.Based on the researched technology and solutions,this article analyzes the functional requirements of the video surveillance system,develops a radar-guided video surveillance system to ensure safe and efficient video encryption,and realizes basic functions such as data collection,monitoring display,video playback,and linkage alarms.The camera can automatically track the moving target through the rotation of the pan-tilt and the zoom of the lens.The system has been actually deployed and used in scenarios such as smart sentry and building security,verifying the feasibility of the proposed method. |
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