The Research Of Wave Measurement Based On Optical Method In Wave Characteristics

In the process of researching and using of the ocean resources,the description of wave characteristics is the most important.The measurement of wave height in laboratory is studied in this paper,and is applied in the large wave flume.First of all,the existing methods of the wave measurement are introduced,including the work principle,the environment of application,the measuring range and the precision,the stability,high consumption,maintenance and other aspects.Based on the advantages and disadvantages,a new method of laboratory wave measurement based on optics is put forward.Secondly,the working principle of measurement method based on optics is: a digital camera is set on the edge of the flume,the surface of the wave and the side wall of the flume are filmed.Images are selected according to the given sampling frequency.Then through the calibration of scale,image segmentation,image graying,image filtering,wave recognition,the wave height can be acquired,based on which wave height and wave period can be obtained with the zero crossing method.The resistance type sensor of wave height and the wave measurement method based on optics were compared.The conclusion is: the precision of measurement method based on optics can be reached 3mm(with a focal length of 8mm).The sampling frequency is 25 frames/sec,which fully meets the demand of laboratory linear wave and nonlinear wave.Again,wave characteristics are analyzed with the results measured above.The analysis of wave shape: the spatial form of wave in large wave flume can be obtained with two temporal forms of wave observed in the large wave flume.Changes of wave height,wave period and wave energy can be more visually observed.Analysis of the wave group propagation process: mainly through the calculation of wave parameters and wave energy process line,changes of parameters of wave group and wave energy can be more visually observed,which can be important factors in ocean engineering.Separation the incident and reflected waves: the incident wave and reflected wave are separated with the method of two points,in order to get the reflection coefficient,which is an important factor in the basic research of marine and coastal hydrodynamics.Finally,the wave measurement based on optics is summarized,and the factors that may cause measurement error are analyzed,and the improvement is pointed out,and the market adaptability is analyzed.