Research On Sonar Image Enhancement Based On Improved Model Of Partial Differential Equation

Ocean exploration is a hot research field in recent years.Due to the particularity of the marine environment,sonar equipment has become an important tool for the development and utilization of the ocean and its resources.The sonar image can reflect the underwater environment,for the scientific research work to provide convenience,but by the influence of imaging method,the underwater acoustic channel and environmental factors such as noise,echo intensity is obtained according to the sonar image is often accompanied by abnormal noise and gray distribution problem.In order to follow the target recognition,image interpretation and other work,it is necessary to denoise and balance the gray level of the sonar image.Image denoising method based on partial differential equation(PDE)has been widely applied in optical image,but its application in acoustic image is relatively few.On the one hand,based on the PM model,TV model,PM regularization model,fourth order YK model and other classical partial differential denoising research model,proposed the improved PDE model of diffusion function and threshold,and the noise reduction effect of simulation results of these models in sonar image,the noise reduction effect of the comparison of the models;on the other hand,the sonar image enhancement in common histogram equalization,gray correction,heading Retinex enhancement and study the gray balance method based on PDE,by adding the direction of diffusion in the partial differential equation of gray balance,the noise and the gray balance in a process synchronization,and sonar image simulation experiments to compare various methods to improve the gray distribution of abnormal.To evaluate the degree of improvement in various methods of sonar image quality in contrast,combining the subjective and objective image quality evaluation standards,strengthen the comprehensive analysis of the effect of multiple images,noise reduction and validation using gray balance effect was measured in the lake and pool experiment real sonar image.Conclusion: the TV model and regularization PM model is suitable for sonar image denoising,denoising and PDE improved model has better noise reduction effect for image polluted;add improved PDE gray balance method of direction diffusion can maintain the image edge details at the same time,to achieve noise reduction and gray equalization,the the sonar image enhancement effect is better.In practical applications,the most suitable enhancement method should be selected in combination with specific enhancement requirements and image features.