Mesh blending

A new method for smoothly connecting different patches on triangle meshes with arbitrary connectivity, called mesh blending, is presented. A major feature of mesh blending is to move vertices of the blending region to a virtual blending surface by choosing an appropriate parameterization of those vertices. Once blending is completed, the parameterization optimization is performed to perfect the final meshes. Combining mesh blending with multiresolution techniques, an effective blending technique for meshes is obtained. Our method has several advantages: (1) the user can intuitively control the blending result using different blending radii, (2) the shape of cross-section curves can be adjusted to flexibly design complex models, and (3) the resulting mesh has the same connectivity as the original mesh. In this paper, some examples about smoothing, sharpening, and mesh editing show the efficiency of the method.     

Implementing an extended functional data model using PS-algol

A number of data models have been proposed in the literature to improve the usability of database systems. Most of these proposals have not been implemented. It is felt that a working implementation is a necessary prerequisite for a serious study of these proposals. So far, implementing data models has been a daunting task, requiring a large team. We report here on a simple implementation technique using the persistent algorithmic language. PS-algol, which promises to make the task of implementing data models a manageable one. The feasibility of the approach is demonstrated by implementing an entity-based functional data model (extended function data model) using PS-algol.     

Adaptive mesh refinement using piecewise-linear shape functions based on the blending function method

Use of quadrilateral elements for finite element mesh refinement can lead either to so-called irregular meshes or the necessity of adjustments between finer and coarser parts of the mesh necessary. In the case of irregular meshes, constraints have to be introduced in order to maintain continuity of the displacements. Introduction of finite elements based on blending function interpolation shape functions using piecewise boundary interpolation avoids these problems. This paper introduces an adaptive refinement procedure for these types of elements. The refinement is anh-method. Error estimation is performed using the Zienkiewicz-Zhu method. The refinement is controlled by a switching function representation. The method is applied to the plane stress problem. Numerical examples are given to show the efficiency of the methodology.     

Generation of dense time series synthetic Landsat data through data blending with MODIS using a spatial and temporal adaptive reflectance fusion model

Landsat imagery with a 30 m spatial resolution is well suited for characterizing landscape-level forest structure and dynamics. While Landsat images have advantageous spatial and spectral characteristics for describing vegetation properties, the Landsat sensor's revisit rate, or the temporal resolution of the data, is 16 days. When considering that cloud cover may impact any given acquisition, this lengthy revisit rate often results in a dearth of imagery for a desired time interval (e.g., month, growing season, or year) especially for areas at higher latitudes with shorter growing seasons. In contrast, MODIS (MODerate-resolution Imaging Spectroradiometer) has a high temporal resolution, covering the Earth up to multiple times per day, and depending on the spectral characteristics of interest, MODIS data have spatial resolutions of 250 m, 500 m, and 1000 m. By combining Landsat and MODIS data, we are able to capitalize on the spatial detail of Landsat and the temporal regularity of MODIS acquisitions. In this research, we apply and demonstrate a data fusion approach (Spatial and Temporal Adaptive Reflectance Fusion Model, STARFM) at a mainly coniferous study area in central British Columbia, Canada. Reflectance data for selected MODIS channels, all of which were resampled to 500 m, and Landsat (at 30 m) were combined to produce 18 synthetic Landsat images encompassing the 2001 growing season (May to October). We compared, on a channel-by-channel basis, the surface reflectance values (stratified by broad land cover types) of four real Landsat images with the corresponding closest date of synthetic Landsat imagery, and found no significant difference between real (observed) and synthetic (predicted) reflectance values (mean difference in reflectance: mixed forest x? = 0.086, σ = 0.088, broadleaf x? = 0.019, σ = 0.079, coniferous x? = 0.039, σ = 0.093). Similarly, a pixel based analysis shows that predicted and observed reflectance values for the four Landsat dates were closely related (mean r² = 0.76 for the NIR band; r² = 0.54 for the red band; p < 0.01). Investigating the trend in NDVI values in synthetic Landsat values over a growing season revealed that phenological patterns were well captured; however, when seasonal differences lead to a change in land cover (i.e., disturbance, snow cover), the algorithm used to generate the synthetic Landsat images was, as expected, less effective at predicting reflectance.     

运用距离测度进行多传感器目标级信息融合

针对多传感器目标级识别问题,提出了一种新的信息融合方法。定义了新的距离测度,通过求解各目标类别与待识别目标的综合距离测度之和最小的优化问题,客观地确定了指标的权重,根据综合距离给出目标识别方法。仿真实验验证了方法的有效性,非常适用于具有多个特征指标的多目标识别领域。     

基于多模型数据融合算法的木材干燥过程建模

提出了一种适合木材干燥过程建模的多模型数据融合算法,通过该方法构建了数据融合模型。分别用BP神经网络和动态递归网络建立了木材干燥基准模型,利用自适应加权算法对两模型输出进行融合,通过实验干燥数据仿真表明:融合后的木材含水率预测值的方差为0.125 3,高于任何一个单独模型的预测精度。     

多传感器图像融合流程建模及仿真

建立图像融合流程并选择最优的融合方法是后续图像融合处理的关键,直接决定了图像融合的效果和应用。分析和研究了多传感器图像融合流程建模方法,建立了一个以图像数据源为入口,以融合模型和融合规则为核心,以融合后图像为输出,以多因素综合判据下的图像融合评价体制为终点的闭环式图像融合流程。最后通过仿真实验,对各自的融合算法和融合规则进行比较,从中选择出容易与主客观评价方法取得一致的,简单实用的,具有与图像数据源和融合目的相适应的融合算法来完成图像融合流程的建模。     

基于知识融合技术的产品设计知识模型研究*

为解决机械产品设计中知识融合的问题,建立了一种基于本体的产品设计知识模型。基于此,提出了一种基于模糊证据理论的融合推理方法,这种方法将模糊集引入证据识别空间中,利用证据合成与决策规则得出知识融合的结果,这种方法弥补了本体建模时的不足并解决了不确定性知识的推理。最后,将该知识模型应用于制造行业产品设计中,帮助制造企业缩短产品设计周期和提高开发质量,同时也有利于产品设计知识的共享和重用。     

基于支持向量机分数等级融合的虹膜识别方法

提出了一种使用支持向量机（Support Vector Machine,SVM）的分数等级融合的虹膜识别方法。通过对虹膜纹理采用小波包分解,选择最高能量区域和次高能量区域提取特征向量,与注册入库的虹膜特征向量计算出海明距离。最后融合两个海明距离输入SVM进行识别。该方法减少输入支持向量机的维数。实验结果表明,该法提高了识别率,能够有效地应用到身份鉴别系统中。     

基于特征融合的多模态身份识别方法研究

研究了多模态身份识别问题,结合人脸和掌纹两种不同生理特征,提出了基于特征融合的多模态身份识别方法。对人脸和掌纹图像分别进行Gabor小波、二维主元变换(2DPCA)提取图像特征,根据新的权重算法,结合两种模态的特征,利用最邻近分类器进行分类识别。在AMP、ORL人脸库和Poly-U掌纹图像库中的实验结果表明,两种模态的融合能更多地给出决策分析所需的特征信息相比传统的单一模态的人脸或掌纹识别具有较高的识别率,更具安全性和准确性。     

基于小波Contourlet变换和区域能量融合规则的图像融合算法*

利用小波-Contourlet变换的多尺度和多方向性特征以及基于区域能量的融合规则在选取融合系数上的优势,提出了一种基于小波-Contourlet变换和区域能量融合规则的图像融合算法,并引入Cycle Spinning来消除变换缺乏平移不变性而引起的图像失真。实验结果表明,该算法明显降低了融合图像的RMSE值,减少了运算时间,达到了良好的视觉效果。     

利用多颜色信息融合的自适应肤色建模

客观世界中存在不同的光照、肤色和人种等因素,通常情况下难以建立一个通用的肤色模型进行各种裸露皮肤的检测。研究了一种自适应肤色建模方法,即利用AdaBoost算法检测人脸,通过这些人脸区域进行肤色建模。为了取得较好的肤色建模效果,适当缩小了由AdaBoost算法检测到的人脸区域;利用多颜色空间信息融合技术,即通过选取多个颜色空间的若干颜色分量,计算待检测图像中这些分量的各自SPM（肤色概率图）,经过“与”运算融合获得最终检测的肤色区域。该算法不需要考虑光照、肤色和人种等因素,是一种自适应的建模过程。实验表明,该算法可以有效解决绝大多数情况下的彩色图像肤色检测问题。     

基于小波变换的Cycle Spinning图像融合的扩展研究

Cycle Spinning是在图像去噪时使用的一种消除伪吉布斯（Pseudo-Gibbs）现象的方法,目前的文献中较少有使用该方法进行图像融合的研究。尝试结合小波变换和Cycle Spinning循环平移的思想,提出了一种基于小波变换的Cycle Spinning图像融合方法,并在此基础上对平移进行了扩展研究。仿真实验证明该方法与传统DWT方法相比,能较好地保留图像的细节信息,获得更高的PSNR值。     

基于PCA和广义高斯建模的多聚焦图像融合

为了提高多聚焦图像的融合性能,针对统计图像融合方法中像素间融合参数估计的不足,提出一种基于小波变换域主成分分析（PCA）和广义高斯建模的多聚焦图像融合方法。将高频子带系数建模为广义高斯分布,并通过改进的最大似然估计法获取融合参数。结合低频子带系数的区域PCA融合方法,最终实现有效的图像融合。实验结果表明,该方法与传统的多聚焦图像融合方法相比,可使融合图像的信息量更丰富,具有更佳的视觉效果。     

结合VAM和模糊逻辑的NSCT图像融合方法

提出一种基于非下采样Contourlet变换（NSCT）的图像融合方法。NSCT分解具有平移不变性,有利于更好地保持原始图像的边缘信息和轮廓结构。由于图像融合任务的不确定性及模糊逻辑在处理该类问题时的优越性,在高低频的融合策略中引入模糊逻辑进行基于隶属度的融合。同时考虑到人类视觉感兴趣区域的重要性,在低频系数的融合中引入视觉注意机制,利用原始图像本身的显著区域信息来指导融合过程,从而在融合过程中最大限度地保留源图像中的显著信息。实验结果表明,算法的融合图像具有良好的视觉效果及客观评指标。     

Decision-level fusion based on wavelet decomposition for induction motor fault diagnosis using transient current signal

In this paper, we propose and implement a decision-level fusion model by combining the information of multi-level wavelet decomposition for fault diagnosis of induction motor using transient stator current signal. Firstly, the start-up transient current signals are collected from different faulty motors. Then signal preprocessing is conducted containing smoothing and subtracting to reduce the influence of line frequency in transient current signals. Next, we employ discrete wavelet transform technique to decompose the preprocessed signals into different frequency ranges of products, and then features are extracted from decomposed detail components. Finally, two decision-level fusion strategies, Bayesian belief fusion and multi-agent fusion, are employed. That is, fault features are classified using several classifiers and generated decisions are fused using a specific fusion algorithm. The proposed approach is evaluated by an experiment of fault diagnosis for induction motors. Experiment results show that excellent diagnosis performance can be obtained.     

基于多重特征选择和多分类器融合的文本层次分类研究

针对大量电子文档需要准确地进行多层次自动分类管理的现实需求,提出基于多重特征选择和多分类器融合技术的层次分类方法。通过引入可信度函数对单分类器效果进行评价,适时采用辅助分类器对较难分类的文档进行分类投票判决。实验结果表明,相对于单分类器,该方法无论在平面分类和层次分类语料上都获得了更好的分类精度,且具有较好的时间复杂性,有很好的实际应用前景。