Presence Of Contours Research Articles

Identifying the manufacturing process of PVC films by nondestructive morphological analyses

This work reports an alternative procedure to identify the manufacturing process used during the production of surfaces with similar chemical composition, specifically, poly(vinyl chloride) (PVC) films produced by casting and calendering methods. The resulting materials are similar in terms of vibrational bands and XRD patterns, and although mechanical properties are different, the analyses require samples with large sizes and can be conducted only before the application of PVC film. Therefore, additional analyses by optical profilometer were used to evaluate morphological differences. The results indicated that the PVC samples produced by casting presented homogeneous and dense topography, while the PVC samples produced by calendering presented micro-sized pores along the surface, which was due to the production process. Thus, the findings suggested that optical profilometer analyses allow the possibility to distinguish between different manufacturing processes of PVC films with greater confidence and is a fast and nondestructive analysis that can be performed in micro-sized samples. The typical procedure includes statistical analyses of surface images, considering topography features, such as the presence of contours, pores, or surface roughness values.

Метод селекции объектов на гиперспектральном изображении на основе анализа их контуров

A new method of spectral selection of given objects on hyperspectral images is considered. At the first stage of the method, hypotheses are tested using the Neyman-Pearson criterion about the presence of object contours in neighboring pixels relative to the simple alternative of their absence consistently over all spectral components. If a decision is made about the presence of a contour in at least one spectral channel, these pixels are analyzed at the second stage with respect to their distribution over the spectral range according to the criterion of maximum a posteriori probability density. Given the values of the mathematical expectation of the gradient difference between the spectral components, hypotheses are formed about the presence or absence of the contour of the desired object. The decision is made on the basis of a comparison of the decision statistics with the likelihood functions. The characteristics of detection and the results of experiments performed on real images are presented.

Method of selection of objects on a hyperspectral image based on the analysys of their contours

A new method of spectral selection of given objects on hyperspectral images is considered. At the first stage of the method, hypotheses are tested using the Neyman-Pearson criterion about the presence of object contours in neighboring pixels relative to the simple alternative of their absence consistently over all spectral components. If a decision is made about the presence of a contour in at least one spectral channel, these pixels are analyzed at the second stage with respect to their distribution over the spectral range according to the criterion of maximum a posteriori probability density. Given the values of the mathematical expectation of the gradient difference between the spectral components, hypotheses are formed about the presence or absence of the contour of the desired object. The decision is made on the basis of a comparison of the decision statistics with the likelihood functions. The characteristics of detection and the results of experiments performed on real images are presented. Keywords: hyperspectral images, contour, gradient, likelihood function.

БІНАРНІ ЛІНІЙНІ ПЕРЕТВОРЕННЯ В МОДИФІКАЦІЯХ АЛГОРИТМУ RSA ШИФРУВАННЯ ЗОБРАЖЕНЬ

The images are one of the most used kinds of the information in modern information company. Therefore actual problems is the organization of protection from unauthorized access and usage. An important characteristic of the image is the presence of contours in the image. The task of contour selection requires the use of operations on adjacent elements that are sensitive to change and suppress areas of constant levels of brightness, that is, contours are those areas where changes occur, becoming light, while other parts of the image remain dark. Mathematically, the ideal outline is to break the spatial function of the brightness levels in the image plane. Therefore, contour selection means finding the most dramatic changes, that is, the maxima of the gradient vector module. This is one of the reasons that the contours remain in the image when encrypted in the RSA system, since the encryption here is based on a modular elevation of some natural number. At the same time, on the contour and on the neighboring contours of the peak villages, the elevation of the brightness value gives an even bigger gap. Problem protect from unauthorized access is by more composite in matching with a problem protect from usage. Basis for organization of protection is the interpretation of the image as stochastic signal. It stipulates carry of methods of encoding of signals on a case of the images. But the images are a specific signal, which one in possesses, is padding to representative selfless creativeness, also by visual selfless creativeness. Therefore to methods of encoding, in case of their usage concerning the images, one more requirement – full noise of the coded image is put forward. It is necessary to make to impossible usage of methods of visual image processing. The algorithm RSA is one of the most used production specifications of encoding of signals. In attitude of the images there are some problems of its encoding, the contours on the coded image are in particular saved. Therefore actual problem is the mining of modification to a method RSA such, that: to supply stability to decoding; to supply full noise of the images. One of pathes of the solution of this problem is usage of affine transformations.

Interaction of electromagnetic radiation with magnetically functionalized CNT nanocomposite in the subterahertz frequency range

The interaction of electromagnetic radiation with a magnetically functionalized nanocomposite based on carbon nanotubes (CNTs) is considered using the model of random distribution of ferromagnetic nanoparticles in the carbon matrix characterized by the presence of resistive–inductive–capacitive coupling (contours). The model is based on the representation of the nanocomposite as a system consisting of the CNT matrix, ferromagnetic nanoparticles, and the interfaces between CNTs and nanoparticles. The wide range of possible resonant phenomena caused both by the presence of contours and the properties of the CNT nanocomposite is shown.

Interactions between top-down and stimulus-driven processes in visual feature integration

Event Abstract Back to Event Interactions between top-down and stimulus-driven processes in visual feature integration Marc Schipper1*, Udo Ernst2, Klaus Pawelzik2 and Manfred Fahle1 1 Bremen University, Department for Human Neurobiology, Center for Cognitive Sciences, Germany 2 Bremen University, Department for Theoretical Physics, Center for Cognitive Sciences, Germany Perception of visual scenes requires the brain to link local image features into global contexts. Contour integration is such an example grouping colinearily aligned edge elements to form coherent percepts. Theoretical and modeling studies demonstrated that purely stimulus-driven mechanisms, as implemented by feedforward or recurrent network architectures, are well suited to explain this cognitive function. However, recent empirical work showed that top-down attention can strongly modulate contour integration. By combining psychophysical with electrophysiological methods, we studied how strongly prior expectations shape contour integration. These empirical techniques were complemented by model simulations to uncover the putative neural substrates and mechanisms underlying contour integration.Subjects participated in two experiments with identical visual stimuli but different behavioural tasks: a detection task (A) and a discrimination task (B). Stimuli consisted of vertical or horizontal ellipses formed by colinearily aligned Gabor elements embedded in a field of Gabors with random orientations and positions. Each hemifield could contain either (i) one vertical, (ii) one horizontal, or (iii) no ellipse. All combinations of these three basic configurations were possible, resulting in nine stimulus categories. In experiment A participants replied ‘yes’ whenever one stimulus contained at least one ellipse, in experiment B observers replied ‘yes’ only when a target was present (either a horizontal or vertical ellipse).The psychophysical data demonstrate a pronounced influence of higher cognitive processes on contour integration: In the discrimination task, reaction times (RT) are consistently shorter for targets than for distractors. The presence of redundant targets (e.g. two horizontal ellipses instead of only one horizontal ellipse) also shortens RTs. These first two effects were consistent with our expectations. Moreover we discovered an additional bias in RT for horizontal ellipses (~70 ms shorter than for vertical ellipses).In EEG recordings, we find pronounced differences in event-related potentials (ERPs) between stimulations with versus without the presence of contours. These differences appear at about 110-160 ms after stimulus onset in the occipital regions of the cortex. In the same regions the evoked potentials were substantially modulated by the number of contours present (~140 ms after stimulus onset) and depending on the behavioural task (~230 ms after stimulus onset). Psychophysical and electrophysiological results are qualitatively consistent: The larger the RT differences, the more dissimilar are ERPs in occipital regions. Moreover, phenomenological modeling reveals that the horizontal bias and task-induced effects either constructively or destructively combine in a multiplicative way. This may lead to much lower RTs when e.g. a horizontal bias combines with a horizontal target, or to a mutual cancellation of the different RT effects when e.g. a horizontal bias combines with a vertical target. Acknowledgments:This work was supported by the BMBF as part of the National Bernstein Network for Computational Neuroscience. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Oral Presentation Topic: Sensory processing Citation: Schipper M, Ernst U, Pawelzik K and Fahle M (2009). Interactions between top-down and stimulus-driven processes in visual feature integration. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.158 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 28 Aug 2009; Published Online: 28 Aug 2009. * Correspondence: Marc Schipper, Bremen University, Department for Human Neurobiology, Center for Cognitive Sciences, Bremen, Germany, schipper.marc@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marc Schipper Udo Ernst Klaus Pawelzik Manfred Fahle Google Marc Schipper Udo Ernst Klaus Pawelzik Manfred Fahle Google Scholar Marc Schipper Udo Ernst Klaus Pawelzik Manfred Fahle PubMed Marc Schipper Udo Ernst Klaus Pawelzik Manfred Fahle Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Role of motion integration in contour perception

Contours are believed to play a key role in the visual analysis of scenes by the primate brain. In dynamic scenes, the presence of contours is often signaled by discontinuities in motion fields. However, it is unclear whether the motion fields over which the visual system extracts discontinuities, correspond to the local optic-flow or the pattern motion fields obtained by integrating local estimates. A resolution of this issue would provide important clues about the organization of visual motion and form analysis processes. In this paper, we present experimental evidence which suggests that the perception of motion defined contours is strongly dependent on motion integration — an operation that is believed to take place relatively late in the visual stream.

Dual oriented mechanisms in contour interaction

Foveal visual acuity is impaired by the presence of contours that surround the target (contour interaction (CI)). In order to determine the roles of various surrounding contours, visual acuities for a square C were measured in the presence of four and two flanking bars. Bars of different orientations relative to the gap of the C produced different CI patterns. The CI produced by a pair of bars was alleviated by adding another pair of bars of an orthogonal orientation. These results indicate that CI is mediated by not one, but at least two orientation selective mechanisms that actively inhibit each other.

Contourless stimuli produce binocular brightness summation

Absolute magnitude estimates by 16 observers reveal that complete binocular brightness summation occurs for flashed Ganzfeld conditions. In other words, the view using both eyes appears twice as bright as with one. However, using the same technique, but with 2° fields, no such summation is found. In addition to showing that, on the average, human observers can act as photometers, the results suggest that either complete summation or averaging of the monocular brightness can occur, depending upon the presence of contours.

Stereopsis generated with Julesz patterns in spite of rivalry imposed by colour filters.

IT is well known that binocular fusion of slightly disparate images from the two retinae can produce a sensation of depth. The presence of contours was considered necessary for this effect until Julesz1 used computer generated “random dot stereograms” to show that a depth percept can occur in the absence of contours, and indeed stereopsis can create contours. The binocular fusion of colours (red and green), on the other hand, has been a highly controversial subject since the time of Helmholtz and Hering. Hecht2 produced a yellow fusion with red and green wratten filters but Hurvich and Jameson3 have criticized his interpretation of the fusion.

Gradients of distortion seen in the context of the Ponzo illusion and other contours.

It is suggested that the spatial distortion evident in the Ponzo figure is a special case of a more general illusion in which a gradient of attenuation appears within areas bounded by angular brackets. The magnitude of this gradient is measured in five lines seen against a number of angular contexts. A similar gradient appears also in the presence of single oblique lines. Accordingly, it is suggested that the distortions seen in the figures usually referred to as “the angle illusions” depend upon the presence of contours which do not necessarily define angles. The implications of these findings for certain existing theories which suggest that some illusions depend upon apparent-distortion of angular size and that they contain features usually associated with two-dimensional perspective projections of typical three-dimensional scenes are discussed.