Research On Wavefront Measurement And Spatial Characteristics Based On Image Recognition

In the wave experiment,the observation of wave elements is an important research content.The measurement of wave height is the most basic of wave elements.The main research object of this paper is the wave tank in the laboratory,and the measurement system is adapted to the large-size wave tank,and a wave surface measurement method based on image recognition is proposed.The main research contents of this paper are as follows:First,this article analyzes the application scenarios,measurement accuracy,range,and stability of wave height measurement methods commonly used in wave observation,and introduces the application of image recognition-based measurement methods in the field of wave measurement,and concludes that image recognition is used in wave measurement.Compared with the unique advantages of traditional measuring instruments,a new laboratory wavefront measurement method--a wavefront measurement method based on image recognition is proposed.Secondly,the principle of image recognition and measurement of the wave surface is introduced: the wall and wave surface of the wave tank are taken from the top view,the continuous wave surface image is obtained by the camera,and the wave height value is extracted by the threshold segmentation to extract the wave surface level value.Use this basic principle and according to the requirements of wave measurement: image distortion correction,image region of interest setting,image grayscale processing,image filtering and enhancement,image binarization,image morphology processing for wavefront pixel coordinate extraction,through The image calibration relationship converts the pixel value into the water level value,and calculates the wave height and periodic wave elements using the zero-crossing method.Then introduce the image recognition and measurement wave height system,according to the requirements of large-scale wave tank wave measurement,select the parameters of the camera in the measurement system layout,spray the ruler on the wave tank wall,and collect video data.Finally,the standard wave height control group was established through manual readings and the data measured by the capacitive wave height sensor were compared with the image recognition wave height measurement results.It was concluded that the image recognition wave height measurement method had better measurement accuracy and met the wave measurement requirements in the wave test.Thirdly,using the results of wave recognition to analyze the nonlinear characteristic quantities of waves in the space and time domains,and count the asymmetry,kurtosis,and skewness of the distribution of the respective wave heights in the space and time domains under regular wave conditions.,And the statistical results of the data show that the trend of the two non-linear characteristic quantities is consistent in the spatial domain and the time domain,and the kurtosis and asymmetry of the spatial domain are larger than the calculated value in the time domain in numerical terms,while the spatial domain The calculated value of skewness on is smaller than its calculated value in the time domain.Under the conditions of the same period and different wave heights,the three characteristic quantities all have a tendency to increase with the increase of wave height.Under the conditions of the same wave height and different periods,the skewness decreases with the increase of the period,and the asymmetry and kurtosis increase with the increase of the period.This conclusion has certain reference significance for future wave morphology research..And using the measurement results of the space wave surface,the regular wave and the irregular wave are separated into and reflected from the wave,which has high application value for the wave separation in the engineering test.Finally,the method of image measurement of wave height is summarized,the cause of measurement error is analyzed,the direction of optimization is proposed,and the application scenarios of the measurement system are analyzed.