Research On Underwater Target Detection Based Laser And Ultrasound

In recent years,the detection activities of human to the ocean is increasing along with the continuous improvement of marine strategic status.The rapid detection and accurate recognition of underwater targets has gradually been a hot research in the field of modern defense and ocean engineering.Currently,sonar detection is still one of the most popular methods which performs well at detecting medium distance and long distance seabed,even in poor underwater environment.But the low sailing speed of ships is a great limitation to its detection efficiency which makes it difficult to carry out a large area and high speed search.Especially for fast-moving and flexible underwater sound targets,can't achieve effective identification and tracking.Therefore,it is of great significance to study more effective detection methods for the detection of underwater targets.In this research,an underwater target detection method combining with ultrasonic and laser is studied,realizing a more effective and comprehensive detection.Using the multi-beam sonar,obtain the characteristic information of the underwater targets,such as contour,location and size.Simultaneously,study a new efficient aerial telemetry technique,achieving non-contact detection of underwater acoustic targets,obtain the frequency characteristic information of the underwater targets.The main contents include the following:Firstly,the basic principle of multi-beam sonar is introduced,including the sounding and water target imaging method.By simulation,the multi-beam sonar is simulated and a high-accuracy underwater sonar detection simulation system is established.Then obtain the sonar image through the simulation and process the image to extract some parameters,such as contour,position and size of the object in the sonar image.The initial location and recognition of the underwater target are realized.Secondly,the underwater acoustic target aerial telemetry technique based on laser Doppler interference is studied.The basic principle of laser interferometry for detecting surface acoustic wave is introduced.Then the time domain and frequency domain characteristics of the scattered light and the reference light interference signal are analyzed by simulation.To get the accurate underwater acoustic signal frequency,methods based on Wavelet Transform and Hilbert-Huang Transform are proposed in this paper and the effectiveness of the methods is verified.In order to classify the underwater sound sources exactly,a method based on Hilbert-Huang Transform and Support Vector Machines is proposed.Finally,an underwater target detection system combining with ultrasonic and laser is built,including the sonar detection system,the underwater acoustic signal laserdetection system and some parameters of the targets in the water.Then collect and separately deal with the underwater ultrasound image and water surface wave interference signal,from which the relevant information of the underwater targets are obtained.The experiments verify the feasibility and accuracy of the algorithm and thereby provide a more favorable basis for the identification of underwater targets.In this paper,the method of underwater target detection is studied from simulation and experiment.The feasibility and effectiveness of the method are described in this paper,which realizes a more effective and comprehensive detection and provides a new idea for positioning and identification of underwater targets.