Image analysis

Multi-way Analysis With Applications in the Chemical Sciences 

Quantitative and qualitative information can be obtained from CSLM images. The results of CSLM analysis are z series or stacks of 2D images taken at a known z axis distance. Commercial software can be used to generate 3D reconstructions. There are several ways to visualize these 3D reconstructions two of the most common ones are the following  

Considering the applications reported later (see Section 4.3), two image analysis methodologies were followed to characterize membrane fouling. 

The development of specialist software for the analysis of electron micrographs has equipped researchers with a variety of computational tools to analyse different types of sample. These methods are all based on the premise that a micrograph is a simple projection of the object and therefore have much in common. The main steps include (i) pre-processing of images, (ii) restoration of images, (iii) enhancement of images, (iv) determination of orientations and (v) reconstmction of the three-dimensional distribution of density. The result obtained must then be validated and interpreted. 

Pre-processing is a set of operations designed to transform the data into the format required for the software, to determine the defocus at which the micrograph was 

Enhancement is the procedure used to increase the signal-to-noise (S/N) ratio of images by averaging. For all types of specimen, there will be local variations in the thickness of the ice film, in concentration of the buffer salts and other contaminants and impurities such as denatured proteins. Random noise variation also arises from the support film and the effects of radiation damage on the ensemble. If 

In reconstruction of the three-dimensional distribution of molecular densities, there are two main approaches. The first is a real space approach and the second a Fourier space approach that is analogous to the crystallographic method. In real space, the back projection technique is used to reverse the operation of obtaining a projection. A projection simply represents the total sum of all densities of the three-dimensional object in a single plane (somewhat like a medical X-ray). To restore the densities of the three-dimensional object the densities of the projections must be extended in the reverse of the projecting direction. There are several algorithms that perform this procedure. 

The Fourier method is based on the central section theorem, which states that the Fourier transform of a projection is a central section in Fourier space. This means that projections at different angles then provide sections of Fourier space at these angles and thus the space can be filled up. We can thus obtain the complete three-dimensional Fourier transform of the object. The reverse Fourier transformation of such a volume will generate the three-dimensional density distribution of the object in real space. For particles with icosahedral or helical symmetry, a Fourier-Bessel transformation is widely used since the use of a cylindrical coordinate system may avoid some interpolation errors. 

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But, with the use of digitization, 2D quantitative measurements are allowed for industrial radiography. These can be done by powerful tools, like estimation of defect extension, automatic segmentation, recognition of individual defects and image analysis (figure 7). For validation, results can be compared with destractive examination of metallic objects. 

In comparison with traditional radiography testing ISONIC system allows to provide image analysis and printout with different sensitivity thresholds at the postprocessing stage... 

The capillary rise on a Wilhelmy plate (Section II-6C) is a nice means to obtain contact angles by measurement of the height, h, of the meniscus on a partially immersed plate (see Fig. 11-14) [111, 112]. Neumann has automated this technique to replace manual measurement of h with digital image analysis to obtain an accuracy of 0.06° (and a repeatability to 95%, in practice, of 0.01°) [108]. The contact angle is obtained directly from the height through... 

Physical testing appHcations and methods for fibrous materials are reviewed in the Hterature (101—103) and are generally appHcable to polyester fibers. Microscopic analyses by optical or scanning electron microscopy are useful for evaluating fiber parameters including size, shape, uniformity, and surface characteristics. Computerized image analysis is often used to quantify and evaluate these parameters for quaUty control. 

Aspect Ratio. The aspect ratio of mica is determined with electromicroscopic image analysis techniques. 

Fig. 7. Definition of diameteis frequently used in image analysis (a) horizontal Martin diameter, (b) horizontal Feret diameter, and (c) diameter of equal...

Fig. 15. Size data for a metal powder obtained by A, image analysis, and B, on a diffractometer.

Fig. 4. Aggregate size distributions by electron microscope image analysis (D and centrifugal (Z9 sedimentations for N220 and N351 carbon blacks (8).

Yes, atomic structures by diffraction defect characterization by systematic image analysis... 

For other quantification, specialized graticules are available, including point counting, grids, concentric circles, and special scales. The latest methods of quantification involve automatic image analysis. 

The first detailed book to describe the practice and theory of stereology was assembled by two Americans, DeHoff and Rhines (1968) both these men were famous practitioners in their day. There has been a steady stream of books since then a fine, concise and very clear overview is that by Exner (1996). In the last few years, a specialised form of microstructural analysis, entirely dependent on computerised image analysis, has emerged - fractal analysis, a form of measurement of roughness in two or three dimensions. Most of the voluminous literature of fractals, initiated by a mathematician, Benoit Mandelbrot at IBM, is irrelevant to materials science, but there is a sub-parepisteme of fractal analysis which relates the fractal dimension to fracture toughness one example of this has been analysed, together with an explanation of the meaning of fractal dimension , by Cahn (1989). 

Exner, H.E, and Hougardy, H.P. (1988) Quantitative Image Analysis of Microstructures (DGM Informationsgesellschaft Verlag, Oberursel). 

Monnier, O., Fevotte, G., Hoff, C. and Klein, J.P., 1997. Model identification of batch cooling crystallizations through calorimetry and image analysis. Chemical Engineering Science, 52, 1125-1139. 

The conformation change in the power stroke has been studied in two ways (1) cryoelectron microscopy together with computerized image analysis... 

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