Papers by Keyword: Image Analysis

Abstract: The precise characterization of the microstructure of bundle is essential for an accurate determination of their properties and behavior. This paper presents a study on the microstructure of continuous fiber bundles by Serial Sectioning Method. Bundle is firstly cured by resin to keep the fiber spatial configuration in the bundle. A series of cross-section images vertical to the bundle direction are captured and polished enough to take digital photographs by the Charge-coupled Device (CCD) microscope. A 3D solid microstructure of the bundle is implemented by linking the correspondent circle for separate fiber in the 3D solid software Pro/E. Reconstructed bundle structure truly represents the spatial configuration of the fibers in the bundle.

Abstract: The size of dispersed nanophases and spaces among them are important factors effeted on toughness of plastic-rubber blends. In order to determine the size distribution of dispersed nanophases and spaces among them, a quantitative method was established by image analysis and transmission electron microscopy of ultra-thin PVC/MBS slices stained by OsO4. Two PVC/MBS blends samples were determined.

Abstract: Nickel-based creep resisting alloys (strengthened by γ´) are the basic materials for high-temperature constructional parts in aircraft engines and energy units. These parts are exposed to combined effects of mechanical stresses, high temperature and dioxide-corrosion conditions. The microstructure changes of cast polycrystalline Ni-based superalloy IN713LC after creep exposure were studied. Three specimens with three different diameters were used for creep tests. The degradation stage (damage parameter π) was determined for all parts of specimens. Individual parts of specimens were metallographic observed and analyzed by image analysis after rupture. The results were compared with model of stress distribution in the specimen with potential damage in the centre of the specimen.

Abstract: This paper investigates the mixing effect in zinc-silica composite electrolyte by particle image velocimetry (PIV) and fractal dimension method. Fifteen groups of orthogonal tests including different rotational speed, electric current and height of paddle are carried out to study the mixing homogeneity using fractal dimension method, it is found that the case with paddle height of 1cm, electric current of 0.25 A and rotational speed of 1000 rpm is better than the others, and at last the distribution of silica in composite coating provides a strong evidence for characterizing the mixing homogeneity.

Abstract: The objective of this study is to develop a numerical model based on microstructural images of concrete and fundamental material properties of each constituent of concrete subjected to alkali-silica reaction (ASR). A microstructure-based finite element approach is employed directly to analyze the mechanical response of concrete to ASR. The modeling work involves acquiring and processing of microstructural images of specimens suffering from ASR using scanning electron microscopy, and implementing finite element program to analyze the microstructural images. The formulation of this model is based on pressure caused by the ASR product and on properties such as Young’s modulus and Poisson’s ratio. The finite element analysis program used to simulate structural behavior of structures attacked by ASR is object-oriented finite element developed at National Institute of Standards and Technology. The numerical results from this model are compared with experimental data, which have been measured using ASTM standard test C1260. The results show that the development and widening of cracks by formation and swelling of ASR gel cause the majority of expansion of mortar specimens rather than elastic elongation due to gel swelling.

Abstract: The determination of dislocation density and in particular the dislocation distribution in SiC wafers is of particular interest for SiC crystal growth development and production. We present an image recognition tool allowing the wafer analysis with specific needs for SiC. In the first stage of expansion, micropipes are selected and counted from SiC wafers that have been etched by KOH.

Abstract: This paper is concerned with the problem of automatic inspection of hot-rolled plate surface using machine vision. An automated visual inspection (AVI) system has been developed to take images of external hot-rolled plate surfaces and the detailed characteristics of the sensor system which include the illumination and digital camera are described. An intelligent surface defect detection paradigm based on morphology is proposed to detect structural defects on plate surfaces. The proposed method has been implemented and tested on a number of hot-rolled plate surfaces. The results suggest that the method can provide an accurate identification to the defects and can be developed into a commercial visual inspection system.

Abstract: In order to determine the content of nitrogen in culture medium at different culture time and compare the nitrogen use efficiency of various plantlets in vitro, near infrared spectroscopy technique and image analysis technique with multi-references were used to obtain the successive information of nitrogen consumption. The models between spectral information and nitrogen content in the medium were established via the partial least squares method together with artificial neural networks. They were used to predict the content of nitrogen in nine test samples. The result showed that the nitrogen use efficiency of incised leaf-type Atractylodes lancea was higher than that of long lanceolate leaf-type, and that of Orychophragmus violaceus was lower than that of Brassica napus. It suggested that the physiological function of the incised Atractylodes lancea was better than that of the long lanceolate.

Abstract: As manual tilt correction has always been the bottleneck of automatic weave image analysis and processing, this paper proposed a means by which automatic weave image tilt correction can be achieved. First, mathematical morphology is carried out in weave image preprocessing for de-noise and enhancement. OTSU and raster scanning are followed to detect target rectangles in the image so as to determine the outlines of interlacing points on which the Interlacing Point Fullness (ISF) is established. Then the relationship between ISF and the correcting angle of weave image is discussed and the correcting coefficient built on ISF is used to counteract the disturbance of weave surface distortions in order to identify the correcting angle in a comprehensive way.

Abstract: Powder of tool steel STN 19830 with 1.9 wt.% of Nb addition was prepared by atomization. Compact material was prepared using of hot isostatic pressing (HIP) and followed by heat treatment to improve the carbides distribution. The aim of this work was to evaluate and quantify the influence of heat treatment parameters on size, shape and spatial distribution of the carbides. Light optical microscopy and image analysis was used to obtain relevant data. Area fraction of carbides was used as parameter of carbide distribution in steel matrix. Sensitivity and accuracy of this method was compared with technique based on Voronoi tessellation. Result shows that size characteristics of tessellation and area fraction analysis are both sufficiently sensitive to indicate the deviation between different states of the respective material and could be used for quantification of size and spatial distribution of the carbides in PM tool steels. Positive effect of used heat treatment on size and distribution of carbides was verified.