In this paper, the novel methods and problems of Concave Hull are given through the scattered points set. The -Concave Hull algorithms, which simply connected region, are proposed based on Graham's scanning of Convex Hull. By the -Hull definition, the Convex Hull is the case when . The -Concave Hull algorithms and Graham's scanning are equivalent when . The experiment of the fault plane extraction of 3D seismic showed that the algorithm is an effective method for the extracting the fault plane problems under the appropriate conditions.

In order to extract the regular interference contained in the multibeam echosounding and eliminate random noise, the novel Envelope Locally Weighted Best Estimation (ELWBE) and the improved NLMF (X-metric non local-mean filter, X-NLMF) methods are proposed. The experimental results show that ELWBE and X-NLMF can not only eliminate the random noise but also give the local optimal estimation on preserving details. Through the experiment, we discover a neglected interference existing in the local area of the central line of the heading. Such interference comes from the heaving and dipping errors, induced fluctuation errors caused by rolling and pitch and some unidentified error sources. The proposed methods lay a good foundation for the further offset correction.

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