頁籤選單縮合
題名 | 應用頻譜分析於推估衛星影像中的波向及水深=Determination of Wave Rays and Bathymetry Using Spectral Analysis on Satellite Images |
---|---|
作者 | 張憲國; 陳台穎; 陳蔚瑋; | 書刊名 | 海洋工程學刊 |
卷期 | 15:3 2015.09[民104.09] |
頁次 | 頁155-167 |
分類號 | 440.98 |
關鍵詞 | 頻譜分析; 衛星影像; 波向線; 水深推估; Fast Fourier transform; Satellite image; Wave ray; Bathymetric estimation; |
語文 | 中文(Chinese) |
中文摘要 | 本文運用直方均化及Butter Worth高通濾波的影像前置處理技術來明示出影像中波峰及波谷的灰階值差異,容易確定傅立葉轉換影像灰階值的頻譜峰值的位置,進而精準地計算波向及波長。本文再利用波浪折射理論來修正原擷取的波長,並由線性波理論的分散關係計算波向線上的局部水深。本文以屏東縣枋寮海岸的實測水深評估本模式推算水深之精度,由結果發現於-4 m至-10 m的計算水深高於實測水深,而在-10 m至-12 m間兩者接近,-12 m以下的水深則略低於實測水深。在選擇9個剖面的估算水深與實測水深的均方根誤差平均值約為0.49 m。若不考慮波紋線較凌亂不規則的部分其均方根誤差則降低至0.31 m,此結果顯示本估算水深的方法是可信的。 |
英文摘要 | Wave rays and bathymetry is determined from preprocessed panchromatic satellite images, in which the techniques of image processing includes histogram equalization and Butter Worth high-pass filter, using the Fast Fourier transformation in this paper. The proposed method is assessed valid for estimating water depth by a comparison of bathymetric variations on 9 chosen beach profiles at the Pingtung coast. The estimated water depths are higher than the measured at between the depths from -4 m to -10 m. However, for deep water exceeding -12 m, the estimated water depths are slightly lower than the measured. Both results are approximate between the depths from -10 m to -12 m. Average of root mean square error between the estimated and measured water depths for nine profiles is 0.49 m. Neglecting three large RMSEs mean RMSE of the remainders is only 0.31 m. The method is evaluated to be suitable for estimating bathymetry and applicable for the planning of coastal engineering in the future. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。