Considered images

Now let us consider imaging by a lens. The disturbance at a point (, r]) in the image plane is given by a superposition of the disturbances from points x, y) across the pupil A, with appropriate propagation delay,... 

So far, we considered image deconvolution assuming that the PSF was perfectly known. In practice, this is rarely the case. For instance, when the PSF is measured by a calibration procedure, it is corrupted by some level of noise. Moreover, if the observing conditions change, the calibrated PSF can mismatch the actual PSF. It may even be the case that the PSF cannot be properly calibrated at all, because it is varying too rapidly, or because there is no time or no means to do such a calibration. What can we do to cope with that ... 

In this section, we will focus on the different types of motion and their experimental determination, and will not consider imaging itself Section 1.5 will then combine the two encodings of position and motion into velocity imaging sequences. 

Fig. 2.9 Schematic diagram illustrating the periodic boundary conditions used in computer simulations. The lines represent cell boundaries. The positions of the particles in each cell, assumed to be five in this example, are identical so that surrounding cells may be considered images of a central one. Each particle is given a different symbol to clarify the imaging effects.

The immediate image is the Gestalt or impact image comprising the initial recognition of the object or scene plus an initial judgement of quality, for example, 1 like the look of this meal . Considered images are of a more... 

In detail, by considering r as the average value of the standard deviations r and q as the average value among the values q for all considered images, respectively, it... 

The main point of our elaboration is, that the Gibbs measure (4) of the potential lattice under interest ctin be considered as a nontrivial prior in the Bayes formula for the conditional probability, applied to the problem of image restoration ... 

A new one-dimensional mierowave imaging approaeh based on suecessive reeonstruetion of dielectrie interfaees is described. The reconstruction is obtained using the complex reflection coefficient data collected over some standard waveguide band. The problem is considered in terms of the optical path length to ensure better convergence of the iterative procedure. Then, the reverse coordinate transformation to the final profile is applied. The method is valid for highly contrasted discontinuous profiles and shows low sensitivity to the practical measurement error. Some numerical examples are presented. 

The visual information provided by radiography images is complex, considering of the great number of disruptive factors. Processed images ate characterized by three particular phenomena ... 

The a priori information involved by this modified Beta law (5) does not consider the local correlation between pixels, however, the image f is mainly constituted from locally constant patches. Therefore, this a priori knowledge can be introduced by means of a piecewise continuous function, the weak membrane [2]. The energy related to this a priori model is ... 

T- and mapped to the image plane considering scaling (Si,Sy) of the coordinate axes and a shift Ci,Cy) of the center of the coordinate system. The distance between X-ray source and image intensifier tube is called /. 

To consider the geometrical magnification of the pipe image on film or IP in the tangential exposure technique according to the set-up shown in fig. 4 a correction of the measured wall thickness (w ) must be performed. The true wall thickness (w) depends in a rather complicated way on the film-focus-distance (f), the radius of the pipe (r) and the radius of the insulation (R) as shown in equation 2 ... 

Considering existing microscopical techniques, one can find that non-destmctive information from the internal stmcture of an object in natural conditions can be obtained by transmission X-ray microscopy. Combination of X-ray transmission technique with tomographical reconstmction allows getting three-dimensional information about the internal microstmcture [1-3]. In this case any internal area can be reconstmcted as a set of flat cross sections which can be used to analyze the two- and three-dimensional morphological parameters [4]. For X-ray methods the contrast in the images is a mixed combination of density and compositional information. In some cases the compositional information can be separated from the density information [5]. Recently there has been a... 

Once a slice has been selected and excited, it is necessary to encode the ensuing NMR signal with the coordinates of nuclei within the slice. For each coordinate (x andy) this is achieved by one of two very closely related means, frequency encoding or phase encoding [1]. In this section we consider the fonner and in the next, the latter. In tlie section after that we show how the two are combined in the most coimnon imaging experiment. 

The history of EM (for an overview see table Bl.17,1) can be interpreted as the development of two concepts the electron beam either illuminates a large area of tire sample ( flood-beam illumination , as in the typical transmission electron microscope (TEM) imaging using a spread-out beam) or just one point, i.e. focused to the smallest spot possible, which is then scaimed across the sample (scaiming transmission electron microscopy (STEM) or scaiming electron microscopy (SEM)). In both situations the electron beam is considered as a matter wave interacting with the sample and microscopy simply studies the interaction of the scattered electrons. 

The ratio of elastically to inelastically scattered electrons and, thus, their importance for imaging or analytical work, can be calculated from basic physical principles consider the differential elastic scattering cross section... 

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