LIP多重微区域分解算法扩展数字图像动态范围

CCD/CMOS 图像传感器的饱和电流和背景噪音使得一次曝光很难超过 60-80dB 的动态范围。用 LIP(Logarithmic image processing)模式将图像转换为灰色调函数,再将基于 LIP 模式的非线性多重微区域图像分解算法进行改进,可以适应不同亮度的单幅图像处理,提高了可分辨信息量和图像对比度,同时抑止了噪声。质量评价显示,该算法能将 MOS 等级四的源图像提高到等级一。     

采用仿射变换的红外与可见光图像配准方法

图像配准是图像融合技术的基本环节和首要问题。针对红外和可见光图像的配准问题,分析了两者配准的特点。引入6参数的仿射变换模型来描述3D空间中的目标,分析了通常采用的4参数模型的不完备性。利用模型计算配准参数,并用最小二乘法达到用多个配准点拟合出最优参数解的目的。实验结果表明,此方法可以很好地消除红外和可见光图像之间的差异。     

基于模态试验与优化的静动力学模型转换

在结构强度分析中,将刚度分布较为准确的静力学模型转换为动力学模型可以大大提高建模效率。提出了一种基于模态试验和优化算法的静、动力学模型转换方法。在调整静力学模型的刚度矩阵基础上,再按照质量、质心、惯矩、单元体积进行节点质量的预分配,最后根据模态试验识别出的模态参数优化节点质量的修正量,如此便可得到其动力学模型。以某飞机翼身组合结构模型的转换为例,证明了该方法的实用性。     

A novel level set method for image segmentation by combining local and global information

A novel level set method integrating local and global statistical information is proposed in this paper. In our method, a new signed pressure force (SPF) function is constructed by two parts. One is the global average intensity of the image, which can accelerate the evolution of the curve when the contour far away from the object boundaries. The other is the intensity average of difference image between the averaging convolution image and the original image, which can guide the evolving curve to catch the boundaries of the objects. In addition, an adaptive weighting function is utilized to adjust the ratio between the global and local terms, which can eliminate the inconvenient selection of weighting parameter. By substituting the new SPF function for the edge stopping function of the geodesic active contour model, we obtain a novel adaptive hybrid segmentation model, which is capable of segmenting the images with intensity inhomogeneity. What is more, in our method, the level set function is initialized with a binary function, which reduces the computational cost for the re-initialization step. The experimental results and comparisons with several popular models on synthetic and real images indicate that our method achieves superior performance in segmenting images with noise, low contrast and intensity inhomogeneity.     

Three-dimensional atomic imaging of Y and (B12)13 clusters in YB56 by HREM and crystallographic image processing

The three-dimensional atomic image of YB₅₆ was obtained by inverse Fourier transformation of three-dimensional phases and amplitudes in three high-resolution images along [100], [110] and [111] of YB₅₆ crystals. After crystallographic image processing, the image directly showed the three-dimensional potential map of the crystal, which showed (B₁₂)₁₃ clusters and Y atom positions. The present method would be useful for three-dimensional structure analysis in nanoscale regions.     

密实型低噪声路面动态模量的超声波法研究

配制了传统的沥青混凝土（AC）、碎石沥青玛蹄脂（SMA）、不同橡胶粉掺量的骨架密实型低噪声路面等3类5个配比的沥青路面，采用超声波法测量了各类沥青路面的动态模量。并且分析了橡胶粉掺量对密实型低噪声路面动态模量的影响，初步得出了以橡胶粉含量为3％的密实型路面的减振降噪效果最好的结论。     

Analysis of cement pastes and mortars by a combination of backscatter-based SEM image analysis and calculations based on the Powers model

Formation of microstructure in cement pastes and mortars were quantitatively analyzed by the SEM-BSE image analysis. Effects of water/cement ratio and of the addition of mineral admixtures on the contents of unhydrated cement particles and pores were discussed. The proportions of each phase obtained by the analyses were compared with proportions calculated on the Powers model. It was found from comparisons that the volume fractions of the residual cement and pores obtained by the image analysis did not contradict those estimated from the Powers model. Lower water/cement ratio pastes and those undergoing pozzolanic reaction showed less fine capillary pores. It was also found that large capillary pores still remained in the mixtures at long ages. The gel/space ratio in the Powers and Brownyard equation was calculated from the phase constituents determined by the image analysis. For mortars without mineral admixture, the gel/space ratio by the image analysis could be related to the strength.