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Computer-aided hip surgery planning and implant design applications require accurate segmentation of femoral head and proximal acetabulum. An accurate outer surface extraction of femoral head using marching cubes algorithm remains challenging due to deformed shapes and extremely narrow inter-bone regions. In this paper, we present an automatic and fast approach for segmentation of femoral head and proximal acetabulum which leads to accurate and compact representation of femoral head using marching cubes algorithm. At first, valley-emphasized images are constructed from original images so that valleys stand out in high relief. Otsu’s multiple thresholding technique is applied to seperate the images into bone and non-bone classes. Region growing method and threedimensional (3D) morphological operations are performed to fill holes in the bone. In the reclassification process, the bone regions are further segmented, and the boundaries of the bone regions are further refined based on Bayes decision rule. Finally, marching cubes algorithm is applied to reconstruct a 3D model and extract the outer surface of femoral head and proximal acetabulum. Experimental results show that this method is an accurate segmentation technique for femoral head and proximal acetabulum and it can be applied as a tool in medical practice. 相似文献
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作为降低柴油机氮氧化物排放的有效手段,高增压和高废气再循环(EGR)技术已受到广泛关注。EGR冷却器是EGR系统中的关键部件之一。而在高性能EGR冷却器的使用保养中,必须消除冷却器中的碳粒堆积物。在之前的相关研究中,已报道过EGR冷却器中碳粒堆积物的特性。利用氧化方法预先调查了换热性能的恶化及堆积质量的相关信息。对堆积层的微观研究揭示了EGR冷却器中堆积物的分布情况。换热管内表面形状对堆积层的厚度影响很大。堆积层的体积密度约为0.2g/cm3,远低于文献报道的颗粒密度。 相似文献
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任何产品随着质量的提高,使用寿命都在相应延长,唯独民用商船(结构)没有做到这一点,这应引起航运业、保险业和相关单位的注意。本文就此问题进行了探讨与展望。 相似文献
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基于应力波的传播理论,对强夯法加固回填土地基机理进行分析,绘制出强夯法加固模式图;讨论了强夯技术参数的选取对地基加固效果的影响,通过工程实例证明强夯法加固地基是一种有效的方法。 相似文献
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当前,国际上使用的锚多种多样,有突出锚“冠”作用的锚,有设稳定杆的锚,也有既不突出锚“冠”又不设稳定杆的锚, 等等。本文着重分析这些锚的优缺点,研制了中远(ZY)型锚,已实船使用6~7年,证明设计性能良好。中远(ZY)型锚在研制时,注重锚的稳定性和自洁能力,有四个尾翼,锚爪重心低,收起方便,施工也方便,ZY-4锚已列入交通部1985年部颁标准,在新造船上推广使用。 相似文献
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