基于相位相关的匀速直线运动模糊图像位移参数估计

为估算匀速直线运动模糊图像的运动参数,提出了一种基于相位相关分析的图像配准方法。该方法利用傅里叶变换的平移特性,对产生平移的目标图像进行傅里叶变换并计算归一化互功率谱,其傅里叶逆变换对应二维脉冲函数,通过计算脉冲函数峰值坐标获取位移图像之间的亚像元级位移量。结合相位相关配准原理和线性空间不变退化模型,给出了匀速直线运动点扩散函数及其光学传递函数的数学描述;讨论了匀速直线运动模糊对相位相关配准结果的影响,证明了图像经过匀速直线运动退化后,位移图像之间归一化互功率谱具有不变性。实验结果表明：动态运动模糊图像最大检测误差为0.489 pixel,标准差为0.16 pixel。     

集成SIFT算法与检测模型优化的UAV影像匹配方法

低空无人机(UAV)测量凭借着低成本、高效率、高精度的数据采集模式,可快速获取高空间分辨率的影像数据,已经成为遥感领域的一种重要技术手段.其中,影像匹配技术是UAV影像数据处理的重要步骤,图像间的匹配直接影响后期三维场景的精度及视觉效果.针对高原山地的高差起伏变化大地形复杂,植被覆被率高及地物分布不规则等问题存在,致使...     

连续激光干扰效果评估方法北大核心CSCD

采用改进后的图像相关度计算方法,在精确配准干扰前后图像的基础上,以像素为单位计算图像相关度,根据人眼识别效果在评估前确定干扰阈值,计算图像有效干扰像元统计值,定量描述激光干扰效果;开展多波段激光干扰成像系统试验,采集不同干扰功率下的激光干扰图像,评估干扰效果。结果表明,该方法能精确识别图像局部变化,客观反映图像质量变化,对各波段不同功率下的激光干扰成像图像给出科学评估结果,对单对图像的处理速度优于s级,具有一定的工程应用价值。     

基于三幅子图的干涉合成孔径雷达数据处理方法研究

现有干涉合成孔径雷达(InSAR)数据处理方法需要单视复图像对包含的所有四幅子图信息, 且生成的干涉相位图去相关噪声非常严重。提出了基于三幅子图的InSAR数据处理方法：等值线相关干涉法, 包括图像对配准和干涉相位图生成。首先介绍了条纹方向图和条纹等值线窗口求取的方法, 并对算法进行了改进, 然后采用相关的方法详细推导了在等值线窗口内InSAR图像的配准和干涉相位图生成的公式。模拟和实测数据表明, 等值线相关干涉法(CCI方法)仅需用InSAR复数图像对的4个实虚部子图中任意3个能得到基本无斑点噪声、无模糊效应的干涉相位图, 并且减少了数据的传输和处理量, 是一种InSAR数据处理的全新方法。     

扩散张量成像的人脑模板构建

扩散张量脑模板包含丰富的大脑白质组织信息,在空间标准化或者脑图谱创建中具有重要价值,然而基于扩散张量模型构建的脑模板精度不高,特别是在脑部复杂的神经元微观结构区域中应用受到限制.针对这一问题,研究者们提出了基于高分辨率扩散成像构建大脑模板的方法.本文对使用扩散张量成像方法进行脑模板构建的研究进展进行了综述,首先介绍了扩散张量脑模板构建的发展进程,阐述了脑模板构建中解决的技术问题及同时存在的局限性;接着详细论述了基于扩散频谱成像及高角度分辨率扩散成像构建脑模板的不同方法间的差异,并总结了这些研究方法取得的重要进展;最后通过分析目前研究进展提出该研究问题中存在的不足以及未来的发展趋势.     

基于特征点的对数极坐标变换图像配准算法

介绍了一种新的图像配准算法,可以很好地解决图像配准中的平移、旋转和缩放问题。算法的实现是首先使用SUSAN算子提取两幅图像的特征角点,剔除虚假的特征点(噪声点),然后使用改进对数极坐标变换和投影相关匹配算法实现特征点匹配;结合亚像素定位技术,可以进一步提高算法的精度。     

一种基于边缘特征的亚像素投影配准算法

为了提高红外图像配准准确度,充分利用图像的边缘信息,结合线性插值,对原有的投影算法引入新的图像相似性评价函数——均方误差函数(Mean Sequare Erron,MSE),提出了基于边缘特征的亚像素投影配准算法.提取图像边缘特征明显的部分做配准能提高匹配概率,引入积分投影能有效降低算法的计算复杂度.算法中还运用了线性插值,使配准准确度达到亚像素级水平.     

三通道偏振成像系统及系统误差校正方法

为了解决现有偏振成像系统难以满足目标检测和跟踪等实时图像处理领域的要求,提出一种实时三通道偏振成像系统,并对该系统存在的视场差异和非一致性误差提出了校正方法.该系统采用三个独立通道采集0°、60°和120°方向上的偏振图像,针对三个独立通道之间存在的视场差异提出了采用尺度不变特征转换配准法进行校正的方法;同时针对三个独立通道之间的灰度响应非一致性现象,根据积分球的退偏特性和探测器的线性响应模型,利用积分球产生完全非偏振光对灰度响应非一致性误差进行了校正.对比实验证明:1)本文提出的三通道偏振成像系统进行校正后的成像效果能够接近单通道偏振成像系统的水平;2)该系统能够在实时采集图像的同时,克服了多通道带来的偏振图像质量下降问题,提高了实用性.     

Four decades of nuclear tracks research in India

The science of solid state nuclear track detectors (SSNTDs)—“Trackology”—developed by R.L. Fleischer, P.B. Price and R.M. Walker in the early 1960s of the last century is an interesting and potentially useful concept with something to offer to almost all branches of science and technology. In fact nuclear tracks find applications wherever solid state damage occurs. Apart from the direct applications of far reaching consequences in nuclear physics, other areas as diverse as bio-medical sciences, cosmic rays and space physics, environmental research, geological sciences, material science, microanalysis, mine safety, nuclear technology, uranium prospecting, etc. have been greatly influenced by SSNTDs.

In this presentation, we attempt to provide an overview of the growth of nuclear tracks research in India over the last four decades and the contributions of various groups from Universities, Institutes, Nuclear Track Society of India and the Department of Atomic Energy in nurturing nuclear track research in the country. Finally, a summary of the significant contributions made by Indian scientists is also presented in this paper along with the overall impact it has made at the national and international level in many areas of basic and applied sciences such as cosmic rays and space physics, fusion–fission and particle evaporation, heavy ion ranges and energy-loss measurements, country-wide indoor radon–thoron survey, geochronology, environmental sciences, track-etch membranes and ion tracks technology, material science, physics and chemistry of fission, etc.     

Super-resolution reconstruction face recognition based on multi-level FFD registration

Super-resolution (SR) reconstruction is an effective method to solve the problem, that the face image resolution is too low to be recognized in video, but the non-rigid change of deformed face and expression changes greatly affect the accuracy of registration and reconstruction. To solve these problems, a method of multi-level model free form deformation (FFD) elastic registration algorithm based on B spline is proposed. It first use low-resolution FFD grid for global registration, to emphasize the contribution of edge information for registration, we introduce edge registration measure into the sum of squared difference (SSD) criterion. Then divide the global registration image and reference image into a series of corresponding sub-image pairs and calculate the correlation coefficient of each pair; at the same time, we do local registration with high-resolution FFD grid to the small value correlation coefficient sub-image pairs. In the registration process of optimization, the paper uses adaptive step length gradient descent method algorithm based on chaotic variables to improve optimization efficiency. After registration, the algorithm of project onto convex sets (POCS) is used to reconstruct SR face image through several low resolution image sequences, and then recognized these SR face images by support vector machines (SVM) classifier. Experimental results from standard video database and self-built video database show that this method can register and reconstruct face image accurately in the condition of great face deformation and expression change, while the face recognition accuracy is also improved.