Research On Hybrid Three-Dimensional Registration Method In Marine Environment Mobile Augmented Reality And Its Application

With the development of marine economy, marine disasters, marine ecology,marine environment, etc.A lot of challenging problems are put forward for marine science research, these problems need to be solved urgently.However, the restriction of the actual marine situation in our country, the marine scientific research personnel lack of sufficient marine data, a lot of research work cannot be carried out smoothly.So, in order to break the deadlock, our country should strengthen and improve the marine monitoring construction by means of developing advanced marine monitoring technology.A large number of firsthand rich marine data can fundamentally strengthen the basis of marine science and technology.Compared with traditional monitoring mode, the offshore video monitoring mode has the advantages as low cost, strong adaptability and wide cover domain, which can monitor the dynamic variation of the offshore sea state in real-time, but it only shows the basic sea condition which the naked eye can identify,the more complex Marine information requires post-processing. ROMS(Regional Ocean Model System) as a new Marine Model System was widely applied in physical oceanography, marine geology and marine acoustics, etc. In the application of physical ocean,it can forecast marine flow field to reflect basic elements of the ocean flow field, but its information is not convenient and intuitional compared with video monitoring.Therefore, the marine environment mobile Augmented Reality system is put forward, which combines mobile video monitoring with ocean flow forecast information. The system can intuitively and dynamically reflect the more complex marine condition.The performance of Augmented Reality system directly depends on the precision of three-dimensional registration. The main task of three-dimensional registration is detecting the location of the user and the line of sight direction in real-time, computing coordinate system according to the calculation of the pose information with virtual information needed in the real three-dimensional space, overlaying the virtual information to the real video sequences.Three-dimensional registration method is mainly divided into two kinds: the based on computer vision and the based on sensors,the registration method based on computer vision has high matching precision withoutother hardware devices, but its image matching algorithm is complex, the system error is difficult to control and it has weak robustness. Three-dimensional registration method based on sensors has good tracking speed and robustness, but it is greatly influenced by the sensor precision, so its accuracy of tracking registered is not high.As a result, a single mode three-dimensional registration of Augmented Reality could not cope with the complexity of the realistic environment, the registration accuracy and effectiveness is restricted, the application of actual scene needs synthesizing multiple tracking methods,the comprehensive tracking mode is called hybrid three-dimensional registration.Therefore, the main work in this paper as follows:1、In view of one sensor can not provide a complete solution for tracking registration in marine environment Augmented Reality system, a mixed registration method was proposed, which integrates with multiple sensors including Assisted Global Positioning System(AGPS), electronic compass and acceleration sensor.Sea-Sky-Line feature rectify the attitude angle measured by sensor to improve the accuracy of tracking registration.2、In view of the problem that sea surface and sky have low contrast, the Hough transform Sea-Sky-Line extraction algorithm based on phase grouping was put forward to compensate for the shortcomings of Hough transform in identifying the low contrast Sea-Sky-Line.3、The prototype system was built in real marine environment with marine numerical forecasting, Android was used and the hybrid registration method was verified.Comparing the Hybrid three-dimensional registration method with the single sensor three-dimensional registration method in precision, as well as the testing of data transmission efficiency of the system. The results show that this technology framework and its registration method has strong availability and practicality, which will have extensive application prospect in marine dynamic environment augmented reality.