| ZHA Guozhen,HE Qingyou,GUAN Changlong,SUN Jian,HE Mingxia. 2016. Speckle suppression in synthetic aperture radar ocean internal solitary wave images with curvelet transform. Acta Oceanologica Sinica, 35(9):13－21 |
| Speckle suppression in synthetic aperture radar ocean internal solitary wave images with curvelet transform |
| 一种基于Curvelet变换的合成孔径雷达海洋内波图像的斑点噪声抑制方法 |
| Received:June 21, 2015 Revised:January 22, 2016 |
| DOI：10.1007/s13131-016-0929-3 |
| Key words:curvelet transform internal solitary wave remote sensing speckle noise synthetic aperture radar |
| 中文关键词: 曲波变换 内孤立波 合成孔径雷达 斑点噪声 遥感 |
| 基金项目: |
| Author Name | Affiliation | E-mail | | ZHA Guozhen | College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China | clguan@ouc.edu.cn | | HE Qingyou | University of Chinese Academy of Sciences, Beijing 100049, China
Physical Oceanography Laboratory, Ocean University of China, Qingdao 266100, China | | | GUAN Changlong | College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China | | | SUN Jian | College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China | | | HE Mingxia | Ocean Remote Sensing Institute, Ocean University of China, Qingdao 266100, China | |
|
| Hits: 2337 |
| Download times: 1151 |
| Abstract: |
| This paper proposes a speckle-suppression method for ocean internal solitary wave (ISW) synthetic aperture radar (SAR) images by using the curvelet transform. The band-shaped signatures of ocean ISWs in SAR images show obvious scale and directional characteristics. The curvelet transform possesses a very high scale and directional sensitivity. Therefore, the curvelet transform is very efficient in analyzing wave signals in SAR images. A noisy ocean ISW SAR image can be decomposed at different scales, directions, and positions using the curvelet transform. The information of the ISWs is centralized in the curvelet coefficients of certain directions under certain scales, whereas the speckle noise is distributed in every scale and direction. By manipulating the curvelet coefficients, the signals of the ISWs can be extracted from the noisy SAR image. Finally, the speckle noise is suppressed and the ISW feature is enhanced by adding the signals of the ISWs back to the original SAR image. Experiments demonstrate the effectiveness of this method. |
| 中文摘要: |
| 合成孔径雷达是海洋内波研究中最重要的工具之一。雷达图像中的斑点噪声会严重降低图像的质量，这一问题在处理和分析信号较弱的二模态内波信号和上升型内波信号时极为明显。合成孔径雷达图像中的海洋内孤立波的信号具有明显的尺度性和方向性。同时，curvelet变换作为一种同时具备尺度分辨率和方向分辨率的数学变换，能够对一幅雷达图像在不同尺度、不同方向和不同位置上进行分析。本文给出了一个基于curvelet变换的合成孔径雷达海洋内孤立波图像的斑点噪声抑制方法。该方法可简述为：(1)对一幅合成孔径雷达海洋内孤立波图像进行curvelet变换，获得curvelet系数；(2)分别仅仅保留一个尺度的系数，将其它尺度的系数置为零，利用处理之后的系数分别重建图像，得到仅仅用一个尺度的系数重建的图像；(3)分别计算上一步中得到的图像的均方差，根据波浪理论，图像的方差代表能量，方差越大则能量越大，以此可以确定内波信息集中的尺度；(4)在每个尺度下，分别计算每个方向的curvelet系数矩阵的平均值，以此确定内孤立波信号集中的方向；(5)在上两步工作的基础上，仅仅保留内波信号集中的尺度和方向的系数，而将其它尺度和方向的系数置为0，得到一幅提取主波信息的图像；(6)将上一步得到的提取主波信息的图像加回到原始图像中，从而达到增强波浪信息并抑制斑点噪声的目的。大量的实验验证表明，该方法不仅能有效地压制斑点噪声，而且能有效地增强波浪信号。 |
|
HTML
View Full Text
View/Add Comment Download reader |
| Close |
|
|
|
