Research On Micro-terrain Exploring Technology Based On Deep-ocean Cobalt-rich Crusts Exploitation (in The Phase Of Shallow Water Experiment)

Deep-ocean cobalt-rich crusts (CRC) is the shell covering top-flat mountains, the top or the slop of sea plateau, under the sea ranging from 500 to 3000 meters deep. Generally, the crust is 2～6 centimeters thick, and it can be 10～20 centimeters thick in high enriched areas which is 800～1500 meters deep under the water. CRC contains manganese, nickel, iron, copper and other common metals. Especially, it is rich in rare and precious metals such as cobalt, platinum and so on. That makes it one of important strategic mineral resources. China has designated an area of 75 thousand square kilometers on the Pacific seafloor as the strategic metal resource base. Thus, the research on the exploiting techniques and equipments is of great economic value and strategic importance.To efficiently control the ore dilution is one of the key techniques to successfully exploit cobalt-rich crusts. When the seam thickness of cobalt-rich crusts and the surface feature of micro-terrain are known, the best cutting depth can be acquired.The main research of the project "Research on detection technology of deep-ocean cobalt-rich crusts micro-terrain and best cutting-depth controlling model"(NO.50474052), supported by the National Natural Science Foundation of China, is to find methods and techniques of detecting the micro-terrain of seafloor which is suitable to exploit CRC. Under the background of the project, the research of this dissertation, from the selection of detecting plan to the construction of micro-terrain DEM, consistently revolved around the two fundamental requirements of good detecting real-time property and high detecting precision in order to provide theoretical guide and experimental basis to construct practical equipment to detect seafloor micro- terrain.The author started with the underwater detecting plan of micro-terrain and put forward a detecting method with a pendulum single beam after consulting a large quantity of acoustic, optical and electronic technique materials on detecting underwater micro-terrain and considering the specific surrounding and methods of exploiting CRC. Then the pendulum single beam bathymeter was constructed. A series of detecting experiments were performed using this equipment. These experiments provided necessary testifying data for the subsequent pretreatment of elevation data and DEM construction.Secondly, the pretreatment of elevation data was realized. Abnormal elevation data is the chief factor leading to produce pseudo-terrain. Additionally, the back side of the slope is unable to be probed by ultrasound, regular grid DEM model must be constructed and other constraints exist. It is necessary to pre-treat elevation data, including rejecting abnormal elevation data, forecasting and revising elevation data and so forth. In terms with these, the author obtained many achievements and inventions as follows:1. Am improved method of data window was used to eliminate abnormal elevation values when the pendulum single beam bathymeter was detecting.2. The filtering of elevation data was conducted by improved median filtering algorithm.3. Support vector machine was used to forecast elevation values in X-axis direction detecting trajectory.4. Forecasted elevation was checked and rectified in the light of slope information.The pretreated elevation data simplified the interpolation of regular grid DEM model of micro-terrain. The elevation of arbitrary interval in X-axis direction was able to be forecasted by way of support vector machine, only the interpolation of elevation in Y-axis direction was under consideration. However, candidate points settled on the line of forecasted elevation in Y-axis direction. The regular grid DEM model of resolution of 25mm can be constructed by way of linear interpolation. The author testified by geometric calculation and verisimilitude assessment that the micro-terrain constructed in above method was qualified to the precision level as practical engineering required.Finally, the author enclosed the VMTerrain visualizing module using VC++ in the AVS/Express software environment, and visualized micro-terrain DEM through this module.