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71.
Lijun Xu Hong Liu Enmin Song Renchao Jin Chih-Cheng Hung 《International journal of imaging systems and technology》2019,29(2):97-109
The segmentation of specific tissues in an MR brain image for quantitative analysis can assist the disease diagnosis and medical research. Therefore, a robust and accurate method for automatic segmentation is necessary. Atlas-based-method is a common and effective method of automatic segmentation where an atlas refers to a pair of image consist of an intensity image and its corresponding label image. Apart from the general multi-atlas-based methods, which propagate labels through the single atlas then fuse them, we proposed a hybrid atlas forest based on confidence-weighted probability matrix to consider the atlases set as a whole and treat each voxel differently. In the framework, we first register the atlas to the image space of target and calculate the confidence of voxels in the registered atlas. Then, a confidence-weighted probability matrix is generated and it augments to the intensity image of the atlas or target for providing spatial information of the target tissue. Third, a hybrid atlas forest is trained to gather the features and correlation information among the atlases in the dataset. Finally, the segmentation of the target tissues is predicted by the trained hybrid atlas forest. The segment performance and the components efficiency of the proposed method are evaluated on the two public datasets. Based on the experiment results and quantitative comparisons, our method can gather spatial information and correlation among the atlases to obtain an accurate segmentation. 相似文献
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77.
Zhigang Yang Zhijia Zhao Jianbo Yu Zhongming Ren 《International Journal of Applied Ceramic Technology》2019,16(4):1381-1389
Textured porous Si3N4-TiB2 composites were prepared by gel-casting–assisted magnetic field alignment technology and subsequent pressureless sintering in the N2 atmosphere. The effects of TiB2 content on grain orientation and properties of composites were studied. Results showed that using the magnetic field of 6T, Si3N4 grains exhibited a high a- or b-axis orientation and TiB2 grains exhibited a high c-axis orientation. In textured green bodies, the increase in TiB2 content from 0 to 20 wt%, the degree of texture of Si3N4 grains showed a slight decrease from 0.78 to 0.71. However, the degree of texture of TiB2 grains was maintained at about 0.98 regardless of TiB2 content. After sintering, except for the Si3N4 and TiB2 phases, new TiN and BN phases also appeared in the samples. Additionally, the sintering process promotes grain orientation of Si3N4 and TiB2. Herein, the degree of texture of TiB2 reached to about 1 regardless of TiB2 content, meaning that the complete grain orientation formed for TiB2. Owing to the reconstruction reaction between TiB2 and N2, new TiN and BN phases did not form the orientation. The increase in TiB2 contents gradually increased the apparent porosity of the textured samples from 27.9% to 39.4%, thereby leading to the decrease in bending strength from 126.8 ± 18.8 MPa to 60.3 ± 11.2 MPa and from 105.3 ± 19.8 MPa to 53.6 ± 13.0 MPa in two directions, respectively. 相似文献
78.
从硬件和软件两个角度出发,介绍基于DSP的多元数据同步采集与存储系统的组成、工作模式以及功能的测试。系统主要由上位机和数字采集与存储单元组成,其中数字采集与存储单元的硬件部分包括电源模块,值班电路模块,数据采集模块,数据存储模块,时钟同步模块。系统采用DSP作为中央处理芯片,利用经过同步后的秒脉冲作为触发信号,实现同步数据采集。以CF卡作为存储介质,实现数据自容式存储。软件部分实现自检、同步、数据采集存储功能。经过测试,系统工作稳定,功能正常,同步精度在100ns以内。 相似文献
79.
Mohammad Afshari Amir-Reza Rouhani Isfahani Saeed Hasani Fatemeh Davar Khadijeh Jahanbani Ardakani 《International Journal of Applied Ceramic Technology》2019,16(4):1612-1621
In the present study, spinel structure CoFe2O4 nanoparticles were successfully synthesized by the sol-gel auto-combustion technique. The effect of apple cider vinegar (ACV) addition as an organic biocompatible agent on the size, morphology, and magnetic properties of CoFe2O4 nanoparticles was investigated in detail. The phase evolution, particle size, and lattice parameter changes of the synthesized phase have been estimated by using Rietveld structure refinement analysis of X-ray powder diffraction data. Also, Fourier transform infrared spectra (FT-IR) of the samples verified the presence of two expected bands correspond to tetrahedral and octahedral metal-oxygen complexes within the spinel structure. Furthermore, microstructural observations revealed that ultrafine particles have a semi-spherical morphology. It was shown that the particles size decreased from ~45 to ~17 nm with an increase in the amount of ACV. Magnetic properties were carried out by vibrating sample magnetometer (VSM) at room temperature. Both the saturation magnetization (Ms) and coercivity (Hc) were found to be significantly dependent on the crystallite size and the amount of ACV. 相似文献
80.
为实现小型磁环表面细微缺陷图像无监督分割,并提高分割精度与计算效率,本文提出了一种基于改进2D Gabor滤波器组的自适应阈值分割方法。首先,利用多尺度、多方向的Gabor滤波器组对缺陷图像进行滤波降噪处理,抑制目标区域与背景区域内部的噪声污染,同时增强区域间的差异性;然后,通过对处理后图像的灰度统计特性分析,根据缺陷图像的灰度均值及方差构造了灰度阈值计算公式,实现了小型磁环表面细微缺陷图像的自适应分割。实验结果表明,本文算法可快速、准确地分割缺陷并抑制噪声干扰,在分割精度、计算效率等方面也优于传统的选择迭代法、OTSU、最大熵等方法,并能够在先进的SEED-DVS8168平台上实时实现,验证了此算法的可行性与实时性。 相似文献