MRI图像的基于窄带的递进多分区C-V分割方法

提出了递进的基于窄带的多分区C-V方法,并对多幅医学脑部MRI图像进行了分割实验。由于该递进方法分为多个阶段,每阶段只需一个水平集函数,并且在每一阶段应用窄带区域,即只处理窄带区域中的点,从而使计算量大大减少。实验结果证明本算法是有效的,在提高计算速度的同时,可大大改进复杂几何结构的分割效果。     

利用视场光阑实现多镜头成像拼接

提出了一种在成像系统前增加视场光阑实现多镜头二维成像拼接的方法,可同时满足大视场成像范围和高分辨力的实际要求。运用光学成像原理把大范围视场分成多个部分,再用多个CCD摄像系统分别对各个小范围视场成像。导出了光阑尺寸的计算公式,从而精确地限制了每个摄像系统的成像范围。对参与成像的各要素如光阑,图像采集镜头,CCD等元件的参数以及它们的相对位置和相互所成角度都进行了数学推导和运算。考虑了物距变化给成像带来的影响,建立了一个相对完整的实物模型。利用此方法进行了成像拼接实验,当景物置于成像系统前2m以外时,拼接成像效果完全达到了实用要求。     

用于大截面传像光纤束的折衍混合光学系统设计

在大截面传像束前置光学物镜设计中,采用“负-正”型式的像方远心光路结构,很好地解决了镜头轴外像差校正和像面照度均匀性问题,同时使镜头结构紧凑、小型化。给出了前置物镜设计实例:工作波长0.8~1.1μm,焦距5mm,相对孔径为1:3.84,光学长度为47mm,视场角为60°。在光学耦接镜设计中采用物方远心光路结构,引入二元光学透镜,通过理论计算和ZEMAX光学软件优化,给出工作波长0.8~1.1μm,焦距33.6mm,光学长度为63.5mm,采用一个衍射面的耦接镜设计实例。该设计结果适用于单丝直径16μm,截面直径6mm的光纤传像束。     

临床质谱学的最新进展:质谱成像方法及其应用

质谱成像技术将基质辅助激光解吸电离质谱的离子扫描与图像重建技术结合,直接分析生物组织切片,产生任意质荷比(m/z)化合物的二维或三维分布图。综述质谱成像原理、方法学及应用发展趋势。     

Profiling and Imaging of Phospholipids in Brains of Abcd1‐Deficient Mice

ABCD1 is a gene responsible for X‐linked adrenoleukodystrophy (X‐ALD), and is critical for the transport of very long‐chain fatty acids (VLCFA) into peroxisomes and subsequent β‐oxidation. VLCFA‐containing lipids accumulate in X‐ALD patients, although the effect of ABCD1‐deficiency on each lipid species in the central nervous system has not been fully characterized. In this study, each phospholipid and lysophospholipid species in Abcd1‐deficient mice brains were profiled by liquid chromatography‐mass spectrometry. Among the phospholipid and lysophospholipid species that are significantly more enriched in Abcd1‐deficient mice brains, VLCFA were present in 75, 15, 5, 4, and 1 species of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, lysophosphatidylcholine, and lysophosphatidylethanolamine, respectively. Most VLCFA were incorporated at the sn‐1 position of phosphatidylcholine and phosphatidylethanolamine. Among the phospholipid species that are significantly less enriched in Abcd1‐deficient mice brains, odd‐numbered saturated or mono‐unsaturated fatty acyl moieties are contained in all phosphatidylcholine species. In addition, a number of phosphatidylglycerol, phosphatidylinositol, and phosphatidylserine species contained highly unsaturated fatty acyl moieties. Intriguingly, 44:1 phosphatidylcholine with VLCFA was mainly distributed in the gray matter, such as the cortex, but not in the white matter in the cerebrum and cerebellum. These results show that ABCD1‐deficiency causes metabolic alternation of long‐chain fatty acids and VLCFA. Moreover, our results imply a molecular mechanism for the incorporation of saturated or monounsaturated VLCFA into the sn‐1 position of phospholipids, and also indicate that the distribution of phospholipids with VLCFA may correlate with the development of X‐ALD.     

陶瓷砖表面质量视觉检测系统研究

重点介绍了机器视觉技术在陶瓷砖表面质量检测中的应用。系统采用面阵摄像机作为测量工具,应用方向算子进行对目标边缘的定位和跟踪,以便获得完整、精确、封闭的目标边缘。实现了对陶瓷砖的边直度、直角度、缺边和缺角等项目的非接触检测。     

复合材料深度方向超声C扫描检测技术

介绍一种基于超声传播时域特性的深度方向超声C扫描成象检测技术,一次扫描可以同时获取被测材料内部若干层的扫描检测图象。     

现代X光电子能谱(XPS)分析技术

现代电子能谱仪有3个主要功能:单色XPS(Mono XPS)、小面积XPS(SAXPS)和成像XPS(iXPS),被认为是光电子能谱仪发展方向。本文介绍这3个功能突出的特点及在材料微分析方面的实际应用。     

电子摄像式对刀仪的研究

研究了电子摄像式对刀仪系统,分析了测量原理与系统结构,对系统的自动调焦与标定方法做了论述。系统实现了数控机床及加工中心中的刀具的刀尖切削点位置、角度、圆角和刃口情况等的自动测量,并将结果存入刀具数据库,具有精度高和自动化程度高的特点,为数控机床的高精度加工提供了保证。实验结果表明,仪器的切削点测量重复性精度达到±2μm。     

VIS/NIR spectroscopy for non-destructive freshness assessment of Atlantic salmon (Salmo salar L.) fillets

Visible/near-infrared spectroscopy has been evaluated for use in freshness prediction and frozen-thawed classification of farmed Atlantic salmon fillets, where fresh samples were stored as whole fish in ice. A handheld interactance probe for performing rapid measurements of single fillets and an imaging spectrometer for online analysis at an industrial speed of one fillet per second, have been used. Freshness as storage days in ice is predicted with an accuracy of 2.4 days for individual fillets, whereas frozen-thawed salmon fillets are completely separated from fresh fillets. The prediction results are comparable to previous results using the Quality Index Method with trained panelists. The region between 605 and 735 nm, which excludes interference by carotenoids and water, is appropriate for both frozen-thawed classification and freshness prediction of salmon fillets. The results indicate that the spectral changes are explained mainly by oxidation of heme proteins during the freeze–thaw cycle and during chilled storage in ice.