基于小波分析的微尺度波斜率波数谱计算

The Computation Method of Micro-Scale Slope Wave Number Spectrum Based on Wavelet Analysis

海面微结构光学测量装置能够获得以颜色表示的海面毛细波和毛细重力波的斜率信息的图像.可以从局部图像计算微尺度波的斜率波数谱.但图像大小有限引起的空间截断导致谱分析时出现频率混叠,表现为数学上的Gibbs现象.本文利用小波分析方法滤除造成频率混叠的重力波,得到海面微尺度波的斜率波数谱.

A sea surface microstructure optical measuring device can be used to obtain images color-coding slope information of capillary and capillary-gravity surface waves on the water surface.According to the slope of local region on the water surface,the slope wave number spectrum of the original image is computed.Because the size of the image is limited,the gravity waves are cut off within a period and the phenomenon of frequency aliasing will appear. This is called Gibbs phenomenon mathematically.So,the wavelet analysis is employed to filter the gravity waves, which can lead to the frequency aliasing. Then the slope wave number spectrum of the micro-scale wave is computed.