用图像分析仪研究矿粉的几何特征

以Quntimet600图像分析仪为测试手段，获得了矿渣微粉试样的级配（颗粒大小及其分布曲线）、颗粒形状因子（圆度，curve length,curve width)等颗粒群特征三维参数，结果表明：（1）矿渣微粉颗粒群的累计质量－粒度分布符合Rosin-Rammler分布和修正的Gauss分布；（2）矿渣是颗粒状粉体，用圆度－粒度、curve length-粒度和curve witdth－粒度分布来描述矿渣微粉颗粒群的形状特征具有较好的规律性，矿渣微粉颗粒群的细组分较接近于球体，而粗组分较接近于长方体。     

GEOMETRIC MODEL AND APPLIED METHOD FOR THE CALCULATION OF GRAIN SIZE DISTRIBUTIONS

Most of the available methods for the calculation of the three dimensional(3D)grain size dis-tribution functions(SDF)are based on the S model and lead a grave systematical error.Theorigin is the basic supposition of spherical grains in the S model,which does not correspondwith the feature of real grains.A new model called A model is developed based on the hypothe-sis of polvhedral grains.The probability functions of the A model and the method to calculatethe 3D SDFs using the A model are given in the present paper.The theoretical analyses andexperimental tests have demonstrated that the A model reduces the systematical error radical-ly.It is nearly as simple as the so far used S model,but gives much better results in repro-ducing of 3D SDFs from the measured ID or 2D SDFs.     

Quantitative serial sectioning analysis: preview

Quantitative serial sectioning analysis provides all of the geometric information that is available from ordinary stereological analysis. In addition, it circumvents the weaknesses inherent in geometric models that are used to estimate distribution functions and topological properties. It further makes accessible some geometric aspects of microstructures that are not available stereologically, even with model assumptions. At the present state of the art it requires a prodigious effort to prepare and analyse a single sample from a single specimen. However, the current generation of image analysing computers already has the capability for automating data collection and analysis, and there is reasonable potential for automating the sample preparation procedure. Quantitative serial sectioning analysis would render obsolete all of the elegant geometrical probability arguments of stereology. Is it the wave of the future?     

Stereology of single objects

Systematic stacks of Cavalieri type, spatial grids, vertical sections and projections, etc., are recent sampling tools for the stereology of single objects, namely of isolated objects that can be orientated and scanned at will in a prescribed way. The increasing use of modern noninvasive scanning devices is facing potential users with the challenge of encompassing the necessary knowledge to implement 'good' stereology. The present paper presents a coherent set of recent stereological methods for single objects in a historical perspective, emphasizing the fact that all relevant techniques — old and new — emanate from a common, relatively small set of basic principles.     

Estimation of structural anisotropy based on volume orientation. A new concept

The quantification of anisotropy—its main direction and the degree of dispersion around it—is desirable in numerous research fields dealing with physical structures. Conventional methods are based on the orientation of interface elements. The results of these methods do not always agree with perceived anisotropy, and anisotropic structures do not necessarily turn out to be ‘anisotropic’ using these methods. In the present paper, we propose an alternative to curve and surface orientation, namely volume orientation. Using trabecular bone as an example of a two-phase anisotropic structure, the new concept is studied in some detail. In particular, a parametric method of estimating volume orientation from sections is presented and discussed.     

x-y-Recording in transmission electron microscopy. A versatile and inexpensive interface to personal computers with application to stereology

An interface for IBM XT/AT-compatible computers is described which has been designed to read the actual specimen stage position of electron microscopes. The complete system consists of (i) optical incremental encoders attached to the x- and y-stage drivers of the microscope, (ii) two keypads for operator input, (iii) an interface card fitted to the bus of the personal computer, (iv) a standard configuration IBM XT (or compatible) personal computer optionally equipped with a (v) HP Graphic Language controllable colour plotter. The small size of the encoders and their connection to the stage drivers by simple ribbed belts allows an easy adaptation of the system to most electron microscopes. Operation of the interface card itself is supported by any high-level language available for personal computers. By the modular concept of these languages, the system can be customized to various applications, and no computer expertise is needed for actual operation. The present configuration offers an inexpensive attachment, which covers a wide range of applications from a simple notebook to high-resolution (200-nm) mapping of tissue. Since section coordinates can be processed in real-time, stereological estimations can be derived directly “on microscope”. This is exemplified by an application in which particle numbers were determined by the disector method.     

Vertical LM sectioning and parallel CT scanning designs for stereology: application to human lung

Practical, unbiased stereological methods are described to estimate lung volume and external surface area, and total volume and surface area of relatively large and anisotropic structures (bronchi and arteries) inside the lung. The volume of each of five lung strata was estimated first by fluid displacement and then by computed tomography (CT) using Cavalieri's method; the reliability of CT was assessed through a calibration procedure, and image thresholding criteria for an accurate volume estimation using CT were established. The parallel, perfectly registered CT section images were also used to estimate the external surface area of each stratum by the spatial grid method. Unbiased estimation of internal surface areas in lung is a long-standing problem: since the structures are large and essentially void, large sections are needed; to facilitate identification, thin sections have to be used for light microscopy, and since such structures are anisotropic, the sections should be vertical. A practical stereological design is demonstrated here on an infant lung, which fulfils all these requirements. This study illustrates the potential of using unbiased stereology to characterize infant pulmonary hypoplasia.     

Stereological estimation based on isotropic slices through fixed points

Stereological estimators of length and surface area based on measurements in an isotropic slice through a fixed point are described. Measurements of three-dimensional angles are not needed. The estimators depend only on distance measurements. The variance of the length estimator is studied in some detail. Applications to particle analysis and second-order stereology are discussed.     

An unbiased and efficient procedure for 3-D connectivity measurement as applied to porous media

A new stereological technique to measure the mean genus (connectivity) per unit volume G_v of a porous medium is described and applied to a real sandstone sample. The technique is based on the ‘net volume tangent counts’ performed on disector samples, i.e. pairs of consecutive sections of an interconnected structure. It consists of a set of simple counting rules applied to the features on the sections of the structure and can be easily implemented manually. The applicability and efficiency of the procedure is evaluated by applying it to a Berea sandstone sample which has been studied previously using a network analysis approach by interactive three-dimensional computer reconstruction. It is shown that the procedure yields results in good agreement with the network analysis result, but has the advantages that it is much easier to implement, is more flexible in how the data are collected, is more efficient, and is known to provide an unbiased estimate of the mean genus per unit volume of the whole structure.     

奶牛乳腺组织体积测量方法的研究

首先,利用机器视觉技术获取奶牛乳房外形的三维描述,并与超声图像分析获得的乳腺分布区域深度信息结合,构建乳腺分布区域的内外层三维网格,从而测算该区域的体积．然后,对乳腺超声图像进行分析,利用局部聚类及区域标记法等分割出乳腺组织部分,并计算乳腺组织的面积密度．最终利用体视学中面积密度与体积密度相等的关系,求得乳腺组织的体积．模拟实验也验证了此方法的可行性．