Advances in Imaging and Electron Physics 

About: Advances in Imaging and Electron Physics is an academic journal published by Academic Press. The journal publishes majorly in the area(s): Scanning transmission electron microscopy & Conventional transmission electron microscope. It has an ISSN identifier of 1076-5670. Over the lifetime, 557 publications have been published receiving 8978 citations. The journal is also known as: Imaging and electron physics.

Ptychography and Related Diffractive Imaging Methods

Abstract: Publisher Summary Ptychography is a nonholographic solution of the phase problem. It is a method for calculating the phase relationships among different parts of a scattered wave disturbance in a situation where only the magnitude (intensity or flux) of the wave can be physically measured. Its usefulness lies in its ability (like holography) to obtain images without the use of lenses, and hence to lead to resolution improvements and access to properties of the scattering medium that cannot be easily obtained from conventional imaging methods. The chapter discusses ptychography in the context of other phase-retrieval methods in both historical and conceptual terms. In an original and oblique approach to the phase problem, it was Hoppe who proposed the first version of the particular solution to the phase problem. The word “ptychography” was introduced to suggest a solution to the phase problem using the convolution theorem, or rather the “folding” of diffraction orders into one another via the convolution of the Fourier transform of a localized aperture or illumination function in the object plane. Apart from computers, the two most important experimental issues that affect ptychography, relate to the degree of coherence in the illuminating beam and the detector efficiency and dynamic range.

The Convex Feasibility Problem in Image Recovery

Abstract: Publisher Summary Image recovery is a broad discipline that encompasses the large body of inverse problems, in which an image h is to be inferred from the observation of data x consisting of signals physically or mathematically related to it. Image restoration and image reconstruction are the two main sub-branches of image recovery. The term “image restoration” usually applies to the problem of estimating the original form h of a degraded image x . The following four basic elements are required to solve an image recovery problem: (1) a data formation model, (2) a priori information, (3) a recovery criterion, and (4) a solution method. The recovery criterion defines the class of images that are acceptable as solutions to the problem. It is chosen by the user on grounds that may include experience, compatibility with the available a priori knowledge, personal convictions on the best way to solve the problem, and ease of implementation. The traditional approach has been to use a criterion of optimality, which usually leads to a single best solution. An alternative approach is to use a criterion of feasibility, in which consistency with all prior information and the data defines a set of equally acceptable solutions. The solution method is a numerical algorithm that will produce a solution to the recovery problem—that is, an image that satisfies the recovery criterion. Modification can be made in two directions: in the conventional image recovery framework, one seeks to preserve the notion of an optimal solution, whereas in the set theoretic framework the emphasis is placed on feasibility.

Redundant Multiscale Transforms and Their Application for Morphological Component Separation

Abstract: Publisher Summary This chapter presents an alternative deterministic methodology, based on sparsity, toward the problem of morphological component analysis (MCA) and anchors this method with some conclusive theoretical results, essentially guaranteeing successful separation under some conditions. The chapter also demonstrates the use of MCA in several applications for images. A major role in the application of the MCA method is played by the dictionaries chosen for decomposition. A wide survey of possible fast-implementation dictionaries taken from the wavelet theory is presented in the chapter, along with ways to use these dictionaries in linear and nonlinear settings. The combination of multi-scale transforms leads to a powerful method in the MCA framework. For some applications such de-noising or de-convolution, MCA is, however, not the best way to combine the different transforms and to benefit from the advantages of each of them.

The principles and interpretation of annular dark-field Z-contrast imaging

Abstract: Publisher Summary This chapter describes the way in which an annular dark-field (ADF) image is formed in a scanning transmission electron microscope (STEM). ADF imaging refers to the use of particular detector geometry in STEM. A geometrically large annular detector is placed in the optical far field beyond the specimen. The total intensity detected over the whole detector is recorded and displayed as a function of the position of the illuminating probe. Because the detector only receives a signal when the specimen is present, the vacuum appears dark, hence the name, and the heavier the atom, the higher the intensity of the scattering, which leads to atomic number (Z) contrast in the image. The most important feature of ADF imaging is that it can be described as being incoherent that has many advantages at atomic resolution. The chapter explains the way in which the image data may be used to provide atomic-resolution information about the specimen.

Modern map methods in particle beam physics

Abstract: Dynamics. Differential Algebraic Techniques. Fields. Maps: Calculation. Maps: Properties. Spectrometers. Repetitive Systems.