Research On Method Of Side Scan Sonar Image Mosaic

The earth is rich in marine resources.With the development and innovation of science and technology,mankind is paying more and more attention to the development and utilization of marine resources.Side scan sonar plays a very important role in ocean exploration,allowing rapid mapping of seabed topography.In this paper,the two parts of side scan sonar image stitching and high resolution imaging are studied,and the principles and methods are analyzed and discussed.The main research contents of the thesis are as follows:(1)By analyzing the working principle of side scan sonar,combined with the mechanism of image distortion,image geometric distortion correction is completed,and the preprocessing of side scan sonar image is realized.Speed distortion correction and slant range distortion correction are performed on the side scan sonar image to eliminate longitudinal and lateral deformation and accurately display the seabed topography.(2)For the problem that the sound image blur can not use the feature points for image stitching,the side scan sonar image data and the coordinate data are combined to realize the geocoding and complete the seamless mapping of the image.Firstly,the latitude and longitude coordinates are transformed into plane coordinates,and the cubic spline function is used to complete the smoothing of the track.Secondly,the side of the triangulation affine transformation is proposed for the problem that the quality of the side scan sonar image obtained by the gap filling method is not high.The information entropy,signal-to-noise ratio and average gradient are used to quantitatively evaluate the image quality.The triangulation affine transformation method can improve the image quality and maintain certain details.(3)The high-resolution imaging method of side scan sonar is studied.Firstly,the signal emission model,probability layer and echo intensity layer in the probabilistic model method are studied.Secondly,this paper proposes a weighted probabilistic model high-resolution imaging method.The pixel method is used to more accurately describe the probability distribution of pixel points in the model.In the process of calculating the gray value of pixel points,the weight of each model is considered by weighting method.Experimental results show that this method can improve the resolution of side scan sonar imaging.