Research On Wake Image Digital Processing

With the development of military technology, marine vessel monitoring and submarines tracking have been listed as important research projects in many countries. Traditional sonar monitoring technology deploys sonar equipment on the seabed and surface ships to search the sound waves sent by submarines. Now lots of submarines use silencing technology so that sonar equipment is difficult to capture signals and difficult to perform monitoring tasks.Surface ships and submarines under the sea will form wake causing by fluctuations while sailing in the sea.According to the characteristics of the wake, non-acoustic detection of submarine hunting techniques are being studied in many countries, mainly using laser, infrared and satellite technology to hunt submarines. Hence, ship wake image digital processing research is a new field of study under this development.This thesis mainly studies four aspects of the ship wake image processing system:the image pre-processing, edge processing and segmentation, information processing and characteristic description. Main work is as follows:First of all, the image of the wake is pre-processed. Through the study of a variety of image pre-processing methods and characteristics, the ship wake image gray-scale transformation method, binary methods and smoothing methods are found fit for this system. According to characteristics of the wake, using the strengthened filter, filter out the noises generated by acquisition devices; then, compression encoding of the image, which has saved storage space.Secondly, wake edge processing and segmentation are done. Extract the image of wake edge using Watershed technique and got a splitting image; extract edge line by using mathematical morphology, then a clear curve of edge has been got.Finally:information and processing of the wake image and descriptions of its characteristics. A sample fitting of wake edge image has been made. Fitting out polynomial equation and image of the wake, describe the numerical value of chain code, the length of shaft, rectangular degree of polynomial image of the wake. The Fourier descriptor experiments have been done, thus getting restructuring wake images.