Research On Forward-looking Scanning Sonar Technology Based On 3D Terrain

ROV pilot training simulator is an equipment using virtual reality thecnology which can simulate ROV's movement and task in the water.As one part of ROV pilot training simulator,forward-looking scanning sonar simulation explores the ROV surroundings.Based on the visual 3D terrain,this paper mainly researches the algnotithm of generating sonar echoes,the algnotithm of inner bounding box,the calculation of target strength,and the analysis of target strength's fluctuation.The article proposes a new algnotithm to improve the effect on removing noise based on the wavelet transform.The main works and innovations are as follows:The article acquires the data of 3D model and calculates echoes' s position of object based on ray-triangle intersection.An improved algorithm based on inner bounding box technology was presented.Experiments showed that the improved algorithm increases the speed of echoes' solving process.This paper uses boundary searching algorithm to draw the outline of discrete points.The article analyzes the parameters of sonar equation and researches the energy loss of acoustic in the spread process.Combining the spread loss model with the planar elements method,the article calculates the ehco intensity of sonar signal.TS distribution model of target strength was deduced based on the generation process of sonar cross section and the fluctuant characteristic of target strength was analyzed.According to the characteristics of underwater noise distribution,this paper proposes a new method of wavelet threshold denoising.In this method,improved wiener flitering is applied to preprocess the image firstly,and then proposes a new threshold function on the basis of soft and hard threshold functions.The new function is applied in wavelet threshold denoising to process the image.Experiment results show that this new method is better than traditional wavelet threshold denoising method.This paper simulates the sonar echo image and non-gaussian distribution noise based on OPENGL.Result shows that the sonar echo simulation method is reliable.