一种基于神经网络的X光图像畸变校正方法

通过对X光图像所产生畸变的分析,提出了一种基于泛化能力的神经网络系统整体校正方法。该方法只需确定网络输入输出和约束条件,无需考虑中间过多的不确定因素,即可建立空间点与图像点的映射关系,然后采用双线性变换进行灰度插值。实验表明,该方法校正效果好,能够满足对图像进行分析处理的要求。     

几种新型号二次离子质谱仪采用的新技术

本文简要叙述法国CAMECA公司 ,德国IONTOFGmbH公司新型的NanoSIMS5 0IMSWFIMSSCUITRATOFSIMSIV型二次离子质谱的特色 ,着重介绍这些仪器改进过的和新增加的仪器部件的原理、性能及功用     

The use of secondary ion mass spectrometry coupled with image analysis to identify and locate chemical elements in soil minerals: The example of phosphorus

The mobility andbioavailability of elements in soils and sediments largely depends on their distribution on the diverse inorganic and organic constituents. This work addresses the example of phosphorus (P) associated to goethite and calcite, that is, to the major minerals involved in the retention of P in soils and sediments in calcareous environments. Synthetic goethite (FeOOH) and calcite (CaCO₃) were reacted with P prior to being analysed by dynamic secondary ion mass spectrometry (SIMS). Powdery samples were embedded in resin, cut in thin sections, and imaged with a Cameca IMS 4F ion microscope used in scanning mode with a primary ion beam of caesium that produced negatively charged secondary ions (?) (Cameca, Cedex, France). Carbon, O, P, and calcium (Ca) were directly imaged at m/z 12, 16, 31, and 40, respectively, while Fe was imaged via the polyatomic ion FeO^? ion at m/z 72. The SIMS data were treated by image analysis procedures. The visual comparison of images and the scatterplot method showed that P strongly interacted with goethite, probably following an adsorption process, and was thus evenly distributed at its surface. Conversely, P was not evenly distributed at the surface of calcite which rather suggests a precipitation process, and the scatterplot method confirmed a poor relationship between P and Ca. For the goethite‐calcite mixture, visual examination suggested that P occurred as clusters which were largely associated with calcite, whereas a statistical analysis of the various images showed that the distribution of P was largely related to that of goethite particles. This work confirms the potential contribution of iron oxides in the retention of P in calcareous environments and shows that coupling image analysis to sensitive analytical techniques such as SIMS is a powerful approach for providing quantitative information on the location of elements at low bulk concentrations.     

鱼眼图像校正软件的关键技术研究

为了满足全景监控工程的特殊要求,选用鱼眼镜头作为图像传感器的成像单元进行图像采集.提出了新的鱼眼图像校正区域的确定方法,并采用球面透视投影和柱面展开两种算法对鱼眼图像进行校正,同时实现虚拟PTZ控制.经测试,该软件对各种监控场合有很强的适应性,能够满足全视场无盲区的监控要求.     

共振扫描显微成像中的图像畸变校正

设计了一种校正算法用于校正双光子荧光显微镜等高速扫描成像系统中共振振镜扫描导致的图像畸变。首先对共振振镜的扫描运动建立模型,推导出非线性扫描的运动公式,进而得到图像畸变公式;然后对一块朗奇光栅样品扫描成像,设计了多峰高斯拟合算法得到光栅所有条纹的宽度变化并通过最小二乘法将条纹宽度数据拟合成一条畸变曲线;最后利用畸变曲线对图像进行校正。结果表明:采用提出的校正算法可使系统最大畸变减小到传统正弦校正方法的1/3,相对畸变减小到1/5,校正效果比传统的正弦校正法提高了2倍。由于提出的曲线拟合校正算法不用增加额外的光路,且不需要切割边缘图像,故显示了极好的图像使用效率和校正效果。     

Three-Dimensional Fusion of Multispectral Secondary Ion Mass Spectrometry Images

Imaging secondary ion mass spectrometry (SIMS) is a powerful surface analysis tool capable of producing two-(2D) and three-dimensional (3D) spatially resolved images of element distributions. Both the 2D and the 3D imaging mode produce multispectral images, i.e., each image stack visualises the lateral distribution of one element, which divides the sample information into a number of individual images. Visual perception of the sample information is aggravated by this—for example, the exact spatial location of different elements relative to each other, formation of occlusions or segregations, etc.—is often hard to recognize when looking at n separate images, especially regarding 3D depth profiles. Image fusion is a process whereby images obtained from various sensors, or at different moments of time, or under different conditions, are combined together to provide a more complete picture of the object under investigation. The use of colour introduces a new dimension of information and can be used to simplify image analysis and object identification. This work introduces a complete methodology that enables the calculation and rendering of 3D colour images of multispectral SIMS depth-profiles based on the use of adaptive color and transparency maps. Examples of 3D SIMS images are given but the technique may be expanded to fusion and visualization of any other multispectral 3D image stack.     

复合校正算法在硬币图像校正中的应用

针对移动硬币图像获取过程中产生的图像失真问题,提出了一种可以获得清晰标准图像的复合校正算法。该算法将透视映射校正与椭圆变换理论相结合,对抓拍到的非静止状态下的失真硬币图像进行还原校正,为获得清晰标准的硬币表面花纹图案提供了一种高效的图像形变矫正手段,降低了硬币图像捕捉环节对机械结构精密度的依赖。实验表明,该算法图像校正精度更高,其图像平均灰度值仅为椭圆直接变换法的10%。     

Tools and procedures for quantitative microbeam isotope ratio imaging by secondary ion mass spectrometry

In this work we demonstrate the use of secondary ion mass spectrometry (SIMS) combined with the Lispix image processing program (Bright 1995) to generate quantitative isotope ratio images from a test sample of a calcium-aluminum rich inclusion from the Allende meteorite that is known to contain discrete mineral grains with perturbed Mg isotopic ratios. Using 19.5 keV impact O- primary ion bombardment and detection of positive secondary ions, microbeam imaging SIMS has allowed us to identify, from the isotope ratio images, enrichments in the 26Mg/24Mg isotope ratio of approximately 5-15% in selected mineral grains. Using custom image processing software, each isotopic ratio image is corrected on an individual pixel basis for a number of factors including detector dead-time, mass bias effects, and isobaric interferences. We have developed procedures for correlating the isotopic images with polarized optical microscopy so that targeted mineral grains could be identified for further SIMS analysis. Finally, additional image processing tools have been developed to allow for pixel-by-pixel evaluation of the influence of detector dead-time and count rate errors on the isotopic ratio images and for correlation of the isotopic images with elemental distribution maps.     

Selection of calcium isotopes for secondary ion mass spectrometric analysis of biological material

The use of stable isotopes as tracers for elemental localization is a function of the background count rate which is dependent upon both the natural abundance and the quantity of interferences at the nominal mass. The occurrence of a variable and unpredictable high background count rate at mass 44+ in biological tissue, probably CO₂+, limits the usefulness of this isotope for physiological problems.     

一种面向球姿态检测的图像透视畸变校正方法

针对球姿态视觉检测中图像的“近大远小”透视畸变问题,提出了一种面向球姿态检测的图像透视畸变校正方法。基于相机成像模型分析了透视畸变的特点及产生原因,根据已知的球体特征模型、相机标定技术和逆透视变换原理构建了图像透视畸变校正模型,进而实现球体任意姿态图像的透视畸变校正。实验结果表明,利用该方法测量直径60 mm以内的球体姿态时平均绝对误差低于0.6°,且该方法适用于工业生产中球体的其他视觉测量。     

DESIGN AND PERFORMANCE OF TWO ORTHOGONAL EXTRACTION TIME-OF-FLIGHT SECONDARY ION MASS SPECTROMETERS FOR FOCUSED ION BEAM INSTRUMENTS

The design and performance of two orthogonal extraction time-of-flight mass spectrometers are reported that were adapted to existing focused ion beam microscopes for secondary ion mass spectrometry. The performances of these designs were compared to that of a prototype previously described by our group. The differences include newly designed transfer ion optics and in the use of a larger microscope chamber. The two new prototypes allow a mass resolving power of either 600 Th/Th (compact design) or 3000 Th/Th (high resolution design) while simultaneously achieving a lateral spatial resolution of less than 50 nm. The spectrometers and their performance (effective ion yield, mass resolving power, lateral, and depth resolution) are described and compared. Additionally, example applications are presented with multivariate statistical methods to visualize the data sets. Both time-of-flight mass analyzers use orthogonal extraction which avoids the need to pulse the primary ion beam, and the of use monoisotopic gallium to preserve the mass resolution. The goal of the design was a cost-effective accessory to augment typical focused ion beam-scanning electron microscopy applications as an alternative to the cost of a dedicated secondary ion mass spectrometer. The modified instrument allows excellent non destructive imaging and easy sample access, and benefits from the presence of complementary non destructive analytical and imaging techniques that exploit the presence of an electron microscope.     

悬臂梁式三坐标测量机的误差分析与修正

根据测量工字钢结晶器型腔的悬臂梁式三坐标测量机的结构进行了全误差源的分析,推导了计算主要误差来源的横臂梁的变形误差的计算数学模型。建立了悬臂梁式三坐标测量机的误差模型,并根据该误差模型进行了误差修正实验。试验结果证明:该误差模型可以减小并修正测量机的测量误差。     

Dynamic-SIMS imaging and quantification of inorganic ions in frozen-hydrated plant samples

We present here SIMS images of the distribution of inorganic cations (Na, K, Mg and Ca) in frozen-hydrated samples of three plant species, ivy, camomile, and flax. The samples were cryofixed using fast plunge-freezing. Stigmatic images were obtained, at 100 K, under dynamic SIMS conditions by fast atom bombarding (FAB). Even though the images obtained with the frozen-hydrated plant samples are still not of upper quality, they show that the method used to prepare these samples preserves existing ionic gradients between the outer and the inner part of the cells, between adjacent cells, including cells with the same type of differentiation, and between tissues. We also describe the quantification of the relative proportions of the ions in the vacuoles of flax. The reasonable accuracy achieved for quantification of the vacuole ion ratios permitted to show (i) that radial gradients of ion ratios in hypocotyls change when the plant is becoming older and (ii) that large differences may exist between adjacent cortical cells of the same type. The role of these substantial differences in vacuole ion balance ratios is a largely unexplored issue in plant physiology.     

基于Top-Hat的硬度压痕测量光照均匀度校正

针对维氏硬度压痕测量过程中由于物理光源照射产生的图像照度不均匀现象,研究了基于数字形态学的Top-Hat算法,对图像光照均匀度进行了校正。并针对传统Top-Hat存在的问题,提出了一种改进的算法。试验证明,该算法可靠有效,能够满足维氏硬度测量的工程实际要求。     

弧形电触头超声C扫描图像校正问题的研究

通过分析弧形电触头钎焊界面的超声C扫描成像原理，发现由于弧面高度的变化引起的反射回波在传播时间上的差异，导致了对缺陷回波采样过程中叠加了表面回波分量，从而形成了在超声C扫描图像中不均匀分布的图像背帚，该背景满足二次曲面形式。根据最小二乘法原理，采用二次多项式拟合图像背景，并根据拟合结果校正超声图像。结果表明，图像背景拟合结果与理论分析一致，通过对弧形触头的超声C扫描图像进行校正，消除了不均匀背景对超声图像的影响，校正后的图像正确反映了钎焊界面缺陷信息，有效解决了弧形电触头钎焊质量超声无损评价问题。     

Subcellular imaging of isotopically labeled carbon compounds in a biological sample by ion microprobe (NanoSIMS)

Here we demonstrate the technique of nanoscale secondary ion mass spectrometry, utilizing the Cameca NanoSIMS50 ion microprobe, to detect and image the metabolism of an isotopically labeled compound (NaH(13)CO(3)) in a biological sample. In particular, we have designed and verified protocols for imaging the subcellular distribution and determining the relative abundance of labeled (13)C, within the coral Galaxea fascicularis. Analyses were conducted on 1-mum thick sections of resin-embedded material, using both scanned (mapping) and static (spot analysis) Cs(+) primary ion beam of approximately 100 nm diameter. Using these samples we establish that NanoSIMS has adequate mass resolution to reliably distinguish (13)C from potential isobaric interference by (12)C(1)H and that data extracted from ion maps are comparable to those acquired by spot analyses. Independent of the method of acquisition, ratioing of (13)C to the naturally abundant (12)C is essential if meaningful data, which can be statistically compared to standard and control samples, are to be obtained. These results highlight the potential of NanoSIMS for intracellular tracking of a variety of organic and inorganic compounds labeled with stable isotopes of C, N, O, S, P, and halogens.     

High spatial resolution secondary ion imaging and secondary ion mass spectrometry of aluminium-lithium alloys

Samples of aluminium-lithium alloys have been observed by scanning ion microscopy and analysed by secondary ion mass spectrometry. The high signal-to-noise ratio of the positive secondary lithium ion opens up the possibility of both high resolution imaging and microanalysis of lithium distributions in aluminium and other materials. Some of the problems encountered due to sample preparation are discussed and ion images of both the artefacts and the true lithium distribution are shown.     

Scanning ion microprobe analysis of composite materials

Applications of scanning ion imaging with high lateral resolution in the microchemical investigation of metal – and ceramic-matrix composites are described. The technique, which combines a scanning ion microprobe with secondary ion mass spectrometry (SIMS), is ideally suited to the study of complex, multicomponent composite structures. Most elements can be detected with good sensitivity, enabling the determination of spatial distributions for major and minor elements. Analytical images obtained with this technique reveal unprecedented chemical information about interfacial segregation and interdiffusion phenomena. As examples, the characterization of both ceramic–matrix (Al borate–SiC) and metal–matrix (Ni alloy–Al₂O₃) composite materials is described.     

二次离子质谱(SIMS)分析技术及应用进展

二次离子质谱 ( SIMS)比其他表面微区分析方法更灵敏。由于应用了中性原子、液态金属离子、多原子离子和激光一次束 ,后电离技术 ,离子反射型飞行时间质量分析器 ,离子延迟探测技术和计算机图像处理技术等 ,使得新型的 SIMS的一次束能量提高到 Me V,束斑至亚μm,质量分辨率达到 1 5 0 0 0 ,横向和纵向分辨率小于 0 .5μm和 5 nm,探测限为 ng/g,能给出二维和三维图像信息。 SIMS能用于矿物、核物质、陨石和宇宙物质的半定量元素含量和同位素丰度测定 ,能鉴定出高挥发性、热不稳定性的生物大分子 ,能进行横向和纵向剖析 ,能进行单颗粒物、团蔟、聚合物、微电子晶体、生物芯片、生物细胞同位素标记和单核苷酸多肽性分型 ( SNP)测定 ,能观测出含有 2 0 0 0碱基对的脱氧核糖核酸 ( DNA)的准分子离子峰。以SIMS在同位素、颗粒物、大分子、生物等研究领域的应用为重点 ,结合实例 ,对 SIMS仪器和技术进展进行了综述