基于优先度排序的3维数据缺失快速插补法

为了快速准确地对3维光学测量的缺失数据进行插值,以利于后期对比研究,提出了基于优先度排序的3维数据缺失快速插补估算方法,并把该算法用于插补模拟实验数据以及20帧振动扬声器测试数据的验证。结果表明,与其它常用缺失数据插补方法相比,该方法运算速度快、插补效果好,有利于处理3维测量结果的多帧和大量的数据。     

基于时空关系和关联规则挖掘的上下文信息缺失插补研究

上下文信息的缺失是上下文信息处理中不可避免的问题,缺失数据插补方法也是数据挖掘中的研究热点。但是,现有的缺失数据的插补方法不太适合上下文信息这一流数据形式,没有充分利用各传感器采集数据之间的关联性,而且在插补的过程中没有考虑传感器数据的时空关系。为了解决现存的缺失数据插补方法的缺陷和不足,该文提出了基于时空关系和关联规则挖掘的上下文信息缺失插补方法(STARM),对传感数据进行空间化和时间序列化,并生成强关联规则对缺失数据进行插补。最后,通过温度传感器采集数据验证了这一算法合理性和高效性。实验证明,该算法在上下文信息缺失估计的准确性要高于简单线性回归算法(SLR)和EM算法等,而且具有较小的时空开销,能够保证实时应用的服务质量(QoS)。     

基于DA多重插补法和电力物联网的电能数据缺失修复方法

针对电力物联网中电能数据量过多,缺失电能数据修复难度较大的问题,研究基于DA多重插补法和电力物联网的电能数据缺失修复方法。电力物联网利用感知层的电能数据采集终端采集电能数据,所采集电能数据利用通信层传送至应用层,应用层的电能数据缺失修复模块,利用EM插补算法计算电能数据缺失值的初始插补值;将所获取的电能数据插补值作为DA多重插补法的初始值,DA多重插补法利用局部加权回归模型,通过调整电能数据缺失值的预测误差,获取最终电能数据缺失修复结果。实验结果表明,该方法修复电力物联网电能数据的观测误差方差低于0.2,对于短期电能数据与长期电能数据,均具有良好的修复结果。     

一种基于稀疏分段的协同过滤推荐算法

针对数据强稀疏性严重制约协同过滤算法推荐准确性的问题,提出基于稀疏分段的改进方法。首先利用基于迭代预测的支持向量回归在解决小样本高维数据中的优势,对稀疏的U-I矩阵中相对弱稀疏的密集数据部分预测缺失评分,然后使用基于项目的插补协同过滤方法预测剩余数据的缺失评分。在多个公开数据集中的实验表明,该方法适用于强稀疏数据集的推荐,与基于项目协同过滤比较可取得较好的预测结果。     

基于三维递归搜索的多级运动估计视频帧率上转换算法

运动补偿插帧是目前主要的帧率上转换方法。为减小内插帧中的块效应,并降低运算量以满足实时高清视频应用,该文提出了一种基于3维递归搜索(3-D Recursive Search, 3-D RS)的多级块匹配运动估计视频帧率上转换算法。该算法将3-D RS与双向运动估计相结合,首先对序列中相邻帧进行由粗到精的三级运动估计,再利用简化的中值滤波器平滑运动矢量场,最后通过线性插值补偿得到内插帧。实验结果表明,与现有的运动补偿插帧算法相比,该算法内插帧的主、客观质量都有所提高,且算法复杂度低,有很强的实用性。     

面向不确定残缺数据的大学生成绩预测方法

大学生在课程规划方面有很高的自由度,这使得成绩数据较不规整,研究者很难对学生的前序课程成绩进行有效分析、利用。已有的成绩预测方法普遍未考虑学生前序课程成绩残缺的现象,从而导致预测准确性不佳。提出一种基于K近邻局部最优重建的残缺数据插补方法,该方法能够有效抑制前序课程成绩缺失对预测模型精度的影响。实验表明,该方法的补全效果优于已有的均值插补、GMM插补等方法,结合随机森林模型实现了有效的成绩预测,为学生成绩管理、就业能力预警提供了客观的参考。     

一种运动自适应的帧内插算法

本文提出了一种运动自适应的帧内插算法,可以用于逐行扫描的数字视频系统中做帧速率转换。该算法首先采用了线性预测块匹配搜索算法来估计内插帧中每一个象素的运动矢量;然后对得到的运动场进行中值滤波和判别,剔除运动不一致或错误的运动矢量;最后沿着运动轨迹线性内插得到内插帧的象素值。仿真分析表明本文提出的算法,在一个大的搜索区域进行快速搜索和判别,可以有效地解决内插帧中快速运动目标的运动模糊和有切换帧时的图象重叠,提高了帧速率转换中内插帧的主观视觉质量。     

基于Matlab的数字扫描变换器设计

描述了数字扫描变换器设计的两种算法结构,即正查数据地址法和倒查数据地址法,采用两种算法来实现扇形扫描的数字扫描变换器中的坐标变换和数据插补,给出相应的Matlab实现程序。实验结果表明,正查数据地址法实现了一维插补,倒查数据地址法实现了二维平面插补,得到的图像都达到预期的效果。     

基于堆叠降噪自编码器的配电数据清洗方法

准确高效的异常数据识别与缺失数据恢复是电力网络稳定运行的基础。提出了一种配网网络状态监测异常数据清洗方法。首先,利用堆叠降噪自编码器(SDAE)学习正常数据和异常数据特征,去除噪声后获取损失函数曲线。然后,采用Bootstrap方法估计置信区间,设置异常数据识别门限,通过多分类支持向量机完成异常类型识别。最后,针对缺失数据,设计了Pearson相关系数进行插补恢复。实验结果表明,该方法能够有效识别配电网络异常数据类型,且缺失数据恢复性能优于现有方法。     

一种运动自适应的帧内插算法

本文提出了一种运动自适应的帧内插算法，可以用于逐行扫描的数字视频系统中做帧速率转换。该算法首先采用了线性预测块匹配搜索算法来估计内插帧中每一年象素的运动矢量；然后对得到的运动场进行中值滤波和判别，剔除运动不一致或错误的运动矢量；最后沿着运动迹线性内插得到内插帧的象素值。仿真分析表明本文提出的算法，在一个大的插索区域进行快速搜索和判别，可以有效地解决内插帧中快速运动目标的运动模糊和有切换帧时的图象重     

Three-dimensional segmentation and interpolation of magnetic resonance brain images

The authors propose a method for the 3-D reconstruction of the brain from anisotropic magnetic resonance imaging (MRI) brain data. The method essentially consists in two original algorithms both for segmentation and for interpolation of the MRI data. The segmentation process is performed in three steps. A gray level thresholding of the white and gray matter tissue is performed on the brain MR raw data. A global white matter segmentation is automatically performed with a global 3-D connectivity algorithm which takes into account the anisotropy of the MRI voxel. The gray matter is segmented with a local 3-D connectivity algorithm. Mathematical morphology tools are used to interpolate slices. The whole process gives an isotropic binary representation of both gray and white matter which are available for 3-D surface rendering. The power and practicality of this method have been tested on four brain datasets. The segmentation algorithm favorably compares to a manual one. The interpolation algorithm was compared to the shaped-based method both quantitatively and qualitatively.     

Morphology-based three-dimensional interpolation

In many medical applications, the number of available two-dimensional (2-D) images is always insufficient. Therefore, the three-dimensional (3-D) reconstruction must be accomplished by appropriate interpolation methods to fill gaps between available image slices. In this paper, we propose a morphology-based algorithm to interpolate the missing data. The proposed algorithm consists of several steps. First, the object or hole contours are extracted using conventional image-processing techniques. Second, the object or hole matching issue is evaluated. Prior to interpolation, the centroids of the objects are aligned. Next, we employ a dilation operator to transform digital images into distance maps and we correct the distance maps if required. Finally, we utilize an erosion operator to accomplish the interpolation. Furthermore, if multiple objects or holes are interpolated, we blend them together to complete the algorithm. We experimentally evaluate the proposed method against various synthesized cases reported in the literature. Experimental results show that the proposed method is able to handle general object interpolation effectively.     

基于双目立体视觉测量原理的物体运动速度测量

采用双目立体视觉测量系统进行炮弹速度的测量, 实现一种利用无速度测量因素测量设备测速的新方法。选择合适参数的两 台摄像机获得被测物体清晰的像,将两台摄像机搭建成光轴平行的双目视觉测量 系统,获得炮弹在运行过程中的每一时刻的三维轮廓数据,根据获得的三维数据进 行空间位置节点的三维插值,得到炮弹在t时间段内运行的距离,并求取平均 速度。仿真实验结果表明,本文方法可以准确、快速利用无速度测量因素的测量 设备获得炮弹的运行速度。     

Registration-based interpolation

A method is presented to interpolate between neighboring slices in a grey-scale tomographic data set. Spatial correspondence between adjacent slices is established using a nonrigid registration algorithm based on B-splines which optimizes the normalized mutual information similarity measure. Linear interpolation of the image intensities is then carried out along the directions calculated by the registration algorithm. The registration-based method is compared to both standard linear interpolation and shape-based interpolation in 20 tomographic data sets. Results show that the proposed method statistically significantly outperforms both linear and shape-based interpolation.     

Adaptive Least Squares Interpolation of Infrared Images

This paper presents an adaptive block-by-block least squares (LS) algorithm for the interpolation of infrared (IR) images. The suggested algorithm is based on the segmentation of the low resolution (LR) image into overlapping blocks and the interpolation of each block, separately. The purpose of the overlapping is to avoid edge effects between blocks. An iterative implementation of the proposed algorithm, which considers the image acquisition model, is used for the minimization of the estimation error in each block. A weight matrix of moderate dimensions is estimated in a small number of iterations to interpolate each block. This proposed algorithm avoids the large computational complexity resulting from the matrices of large dimensions required to interpolate the image as a whole. The performance of the proposed algorithm is compared with the standard as well as the warped distance optimal interpolation of maximal order with minimal support (O-MOMS) algorithm from the peak signal-to-noise ratio (PSNR) point of view. Numerical results reveal the superiority of the proposed LS algorithm to the cubic O-MOMS algorithm.     

Fast frequency sweep technique for the efficient analysis of dielectric waveguides

This paper describes a new approach to spectral response computations of an arbitrary two-dimensional (2-D) waveguide. This technique is based on the tangential-vector finite-element method (TVFEM) in conjunction with the asymptotic waveform evaluation (AWE) technique. The former is used to obtain modes characteristics for a central frequency, whereas the latter employs an efficient algorithm to compute frequency moments for each mode. These moments are then matched via Pade approximation to a reduced-order rational polynomial, which can be used to interpolate each mode over a frequency band with a high degree of accuracy. Furthermore, the moments computations and subsequent interpolation for a given set of frequency points can be done much more rapidly than just simple simulations for each frequency point.     

基于改进三维后向投影的多圈圆迹SAR相干三维成像方法

圆迹SAR(CSAR)因其特殊曲线运动轨迹而具备3维成像能力。单圈CSAR理论上可以获得距离方位平面亚波长级的分辨率,但是高程向分辨率却很低。同时,利用后向投影(BP)算法进行CSAR 3维成像的算法复杂度高,成像效率低。该文提出一种基于改进3维后向投影的多圈CSAR相干3维成像方法,针对现有成像算法时间复杂度高的问题,提出一种构造几何插值核的CSAR改进3维后向投影算法,可将3维插值操作转化为1维插值操作和距离向量搜索操作,通过多圈CSAR改进3维后向投影成像结果相干积累的方式得到最终3维图像。该文所提方法可有效解决单圈CSAR 3维成像高程向分辨率低的问题,改善3维成像细节,同时能够大幅降低CSAR 3维成像时间。仿真圆锥目标和美国空军实验室GOTCHA数据3维成像结果验证了该文所提方法的有效性。     

基于截断sinc插值的毫米波全息成像算法优化

针对毫米波系统在二维横断面成像时,空间频率间隔上非均匀性影响成像精确度问题,提出基于截断正弦基数(sinc)函数的插值优化算法。算法取sinc函数为卷积核,对数据进行插值,相较细胞元插值法,得到的散射插值幅值更接近实际值,成像精确度更高。在此基础上,由于sinc插值需要无穷项求和,所需计算的数据量巨大,因此对插值求和项进行截断处理,对不同截断点数所成横断面像作比较,进一步优化成像质量。仿真结果验证了算法的可行性和精确性。     

TD-LTE-A上行信道估计中基于加权的插值算法

TD-LTE-A上行信道估计中的线性插值算法只利用数据两端的两个导频位置的信道响应进行插值,不能很好拟合信道响应。针对此问题,提出了基于加权平均的插值算法。该算法以线性插值算法为基础,首先利用连续3个导频位置的信道响应进行线性插值得到数据位置的两个初步插值结果,再在此基础上引入权值α,最后对初步插值结果进行加权得到数据位置的信道响应。在EPA环境下的MATLAB仿真结果表明,相对于线性插值算法,基于加权的插值算法在不过度增加计算复杂度的情况下能降低系统的误比特率。     

Combining a morphological interpolation approach with a surface reconstruction method for the 3-D representation of tomographic data

In this paper, a new interpolation scheme, based on Mathematical Morphology and a modified Marching Cubes (MC) Algorithm to reconstruct 3-D anatomical structures is presented. The proposed interpolation technique is implemented using morphological operations and incorporates a distance function to improve the computational effectiveness of the technique. The morphological interpolation technique is compared to an existing shape based interpolation method and its advantages include superiority capability on handling various cases such as the branching and holes problem (appearance and disappearance of information) and more accurate volume estimation. Furthermore, the morphological technique is companied with a 3-D reconstruction algorithm capable of representing any anatomical structure from real 3-D medical data. Introducing a novel general rule, the algorithm triangulates all standard cube configurations introduced from the standard MC algorithm, without producing topologically incoherent surfaces or holes. Finally, the technique is implemented in JAVA and its output is in VRML 1.0 format; therefore it can be executed over the internet and implemented for telemedicine applications.