Research And Visualization Of Underwater Acoustic Data Based On Volume Rendering

There are many types of underwater acoustic data,which contain a lot of information.Researchers need to process the received sonar signal through a series of methods to extract useful information.The underwater environment is complex,and the sea surface and the sea floor will reflect sound waves,so that there is noise in the received sonar signal,so the signal needs to be reduced in noise.In addition,the underwater sound source will emit sound waves in a horizontal 360-degree direction.If viewed from a vertical section,the sound waves propagate through simple harmonic-like methods.Understanding the propagation method of sound waves in the underwater acoustic field will help a variety of underwater detection activities Therefore,the visual presentation of the underwater sound field is of great significance.This article mainly studies these two aspects,the main research content and results are as follows:Firstly,for the phenomenon that the signal received by passive sonar contains environmental noise,this paper improves the traditional wavelet threshold noise reduction algorithm and applies it to the passive noise reduction signal preprocessing.The algorithm applies the hyperbolic function and exponential function to the wavelet threshold function.The wavelet coefficients within the positive and negative thresholds are processed using the exponential function,and the wavelet coefficients outside the positive and negative thresholds are processed using the hyperbolic function.The threshold function is continuous,so it can overcome the pseudo Gibbs phenomenon caused by the direct truncation of the hard threshold function,and the asymptotic slope of the hyperbolic function used by the threshold function is 1,so it can overcome the existence of the soft threshold function.There is a constant deviation between the original wavelet coefficient and the original wavelet coefficient,so that the noise reduction effect is not ideal.Experiments show that the improved wavelet threshold denoising function has been used in passive sonar signal denoising to achieve good results.Secondly,this paper designs a visualization method of underwater sound field based on ray casting algorithm,and in order to make the underwater sound field have better visualization effect,after analyzing the three-dimensional data of underwater sound field,the corresponding color value transfer function and opacity are designed.Transfer Function.First,the scalar value in the underwater acoustic field,that is,the transmission loss value,is mapped to 64 colors in the reverse jet color mode in MATLAB using a ramp-type transfer function.Then calculate the gradient amplitude of the underwater acoustic field data,set an appropriate threshold,and the data points with a gradient amplitude greater than the threshold are considered as boundaries.This part will be mapped to opacity through a logarithmic transfer function.The rest The data point is considered to be an internal point,and the transfer loss value is mapped to opacity through a ramp-type transfer function,and finally the two are combined to obtain the final drawing effect.The above transfer function is applied to the visual presentation of the underwater sound field,a good rendering effect is achieved.The experimental results show that the research work in this paper can remove the environmental noise to a certain extent and make the boundary of the visualization of the underwater sound field clear,and the image is clear and easy to observe.