Research On The Key Technology Of Multi-beams Measured Data Processing

Undersea terrain detection is the foundation of marine resource development and engineering construction. The multi-beam bathymetric system is one of the main equipment to obtain seafloor topography. At present, most of them we use are introduced from oversea and there is no knowing what the intermediate results of data processing and its technologies are. So, the research on key technologies of multi-beam measured data processing can not only contribute to fully understanding and learning of their data processing methods, but also be able to obtain the intermediate results of data processing. Furthermore, the research works will also provide theoretical references for development on our multi-beam data processing technologies and widen the scope of the measured data.The multi-beam measured data mainly include bathymetric data and image data. Currently, the original data format is not fully open and there are many mistakes for the multi-beam system from oversea. In this paper, taking Simrad EM300X series multi-beam measured original data as experiment object, we have developed the data extraction system based on the storage mode and structures of measured data by manually analyzing large amounts of raw binary data files. The system is able to produce text or excel format file that contain bathymetric data, echo intensity data, location data, attitude data and sound speed profile. It will provide foundation for the study of the multi-beam data processing technology.In this paper, we have studied the technologies of the depth data consolidating, location computing, data filtering, data re-sampling and discussed the data thinning method in detail. We have proposed a new data thinning method which combined the angle-chord joint criterion with the point cloud dispersion thinning method. Based on the mathematical simulation typical terrain and multi-beam measured swath data, the experiments have done and the results showed that the geometric features of bathymetric data are well preserved and the data thinning rate remained at a high level.The major techniques of the multi-beam image data processing, such as formation principle, error sources, correction and graphical representation methods, have been researched. The original sonar image is obtained by calculating the position and the echo intensity data. The test applied conventional image processing methods to sonar image have done and its results show that the median-filtering and wavelet analysis denoising can be better smoothing and histogram correction techniques can significantly protruding image features.The main principle of the multi-beam data processing and mapping software abroad has been achieved by studying the key technologies of the multi-beam data processing and it will lay the foundation for development on our multi-beam data processing system with self-owned intellectual property rights.