A novel nonlinear gray transform method is proposed to enhance the contrast of a typhoon cloud image.Generally,the typhoon cloud image obtained by a satellite cannot be directly used to make an accurate prediction of ...A novel nonlinear gray transform method is proposed to enhance the contrast of a typhoon cloud image.Generally,the typhoon cloud image obtained by a satellite cannot be directly used to make an accurate prediction of the typhoon＇s center or intensity because the contrast of the received typhoon cloud image may be bad.Our aim is to extrude the typhoon＇s eye in the typhoon cloud image.A normalized arc-tangent transformation operation is designed to enhance global contrast of the typhoon cloud image.Differential evolution algorithm is used to choose the optimal nonlinear transform parameter.Finally,geodesic activity contour model is used to extract the typhoon＇s eye to verify the performance of the proposed method.Experimental results show that the proposed method can efficiently enhance the global contrast of the typhoon cloud image while greatly extruding the typhoon＇s eye.展开更多
舰船辐射噪声由于包含舰船声源吨位、航速、螺旋桨特征等信息,一直是舰船识别研究的重点与难点,对国计民生具有重大意义。本文以舰船辐射噪声为主要对象,针对Alpha稳定分布噪声环境下舰船识别的问题进行研究。选用反正切非线性变换的方...舰船辐射噪声由于包含舰船声源吨位、航速、螺旋桨特征等信息,一直是舰船识别研究的重点与难点,对国计民生具有重大意义。本文以舰船辐射噪声为主要对象,针对Alpha稳定分布噪声环境下舰船识别的问题进行研究。选用反正切非线性变换的方法抑制背景噪声的影响,再提取1.5维谱特征输入基于粒子群优化算法的识别器进行识别。仿真实验表明,当混合信噪比高于-5 d B时,舰船辐射噪声的识别率高于90%。实际舰船辐射噪声信号实验进一步验证了本文算法的有效性。展开更多
本文提出了一种混合滤波器的方法,采用扩展的Sigmoid变换,使缺陷及边界的灰度值得到加强,再通过LoG(Laplacian of a Gaussian)算子进行目标轮廓检测和相似区域的分割,最后进行细化。结果表明,该方法相对传统的中值滤波阈值分割方法能取...本文提出了一种混合滤波器的方法,采用扩展的Sigmoid变换,使缺陷及边界的灰度值得到加强,再通过LoG(Laplacian of a Gaussian)算子进行目标轮廓检测和相似区域的分割,最后进行细化。结果表明,该方法相对传统的中值滤波阈值分割方法能取得较好的检测效果。展开更多
基金supported by National Natural Science Foundation of China (No. 40805048,No. 11026226)Typhoon Research Foundation of Shanghai Typhoon Institute/China Meteorological Administration (No. 2008ST01)+1 种基金Research Foundation of State Key Laboratory of Remote Sensing Science,Jointly sponsored by the Instituteof Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University (No. 2009KFJJ013)Research Foundation of State Key Laboratory of Severe Weather/Chinese Academy of Meteorological Sciences (No. 2008LASW-B03)
文摘A novel nonlinear gray transform method is proposed to enhance the contrast of a typhoon cloud image.Generally,the typhoon cloud image obtained by a satellite cannot be directly used to make an accurate prediction of the typhoon＇s center or intensity because the contrast of the received typhoon cloud image may be bad.Our aim is to extrude the typhoon＇s eye in the typhoon cloud image.A normalized arc-tangent transformation operation is designed to enhance global contrast of the typhoon cloud image.Differential evolution algorithm is used to choose the optimal nonlinear transform parameter.Finally,geodesic activity contour model is used to extract the typhoon＇s eye to verify the performance of the proposed method.Experimental results show that the proposed method can efficiently enhance the global contrast of the typhoon cloud image while greatly extruding the typhoon＇s eye.
文摘舰船辐射噪声由于包含舰船声源吨位、航速、螺旋桨特征等信息,一直是舰船识别研究的重点与难点,对国计民生具有重大意义。本文以舰船辐射噪声为主要对象,针对Alpha稳定分布噪声环境下舰船识别的问题进行研究。选用反正切非线性变换的方法抑制背景噪声的影响,再提取1.5维谱特征输入基于粒子群优化算法的识别器进行识别。仿真实验表明,当混合信噪比高于-5 d B时,舰船辐射噪声的识别率高于90%。实际舰船辐射噪声信号实验进一步验证了本文算法的有效性。
