1,720,971 research outputs found
Freeze-etched collagen fibril surface structures: shape-from-shading recovery and computer modelling.
No full textProgettazione e realizzazione del Museo virtuale della vita quotidiana a Bologna.
No full textl progetto MUVI – Museo Virtuale della Vita Quotidiana nasce da una riflessione sui musei anglosassoni dedicati alla vita quotidiana. Questo tipo di museo, attraverso la ricostruzione di interni domestici relativi a varie epoche storiche e ceti sociali differenti, mette in mostra oggetti e fonti storiche ricollegabili alla vita di tutti i giorni. L’alimentazione, l’aggregazione familiare, gli oggetti di uso quotidiano raccontano storie ed esperienze
MOBIE: A movie brain interactive editor
No full textInteractive cinema will soon be a reality, following the current evolution of computer games. So far, however, interactivity is still limited, in particular because it is based on conscious operations of the viewer (e.g. through buttons, joystick, keyboards, voice, gestures). Instead, it would be desirable to adapt the movie plot to the viewers state of mind, without the need of deliberate actions, just by means of thoughts, unconscious preferences, and feelings. Such an interaction would represent an interesting alternative to traditional ways of movie watching, and an advance with respect to more mechanical types of interactivity
Shape from Motion Project: 3D Modelling by Analogic Video Input Data for the Reconstruction of Archaeological Sites
No full textOne of the fundamental problems in early Computer Vision is the measurement of optical flow. In many cases when a scene is observed by a camera there exists motion, created either by the movement of the camera or by the independent movement of objects in the scene. In both cases the goal is to correspond to each visible point a 3D velocity vector. In general, it is impossible to infer from one view the 3D velocity map. However most motion estimation algorithms calculate the projection of the velocity map onto the imaging surface. A large number of different algorithms have been developed in order to solve this problem.
The problem of estimating the optical flow has received much attention because of its many different applications. Tasks such as passive scene interpretation, image segmentation, surface structure reconstruction, inference of egomotion, and active navigation, all use optical flow as input information.
Until now, most motion estimation algorithms consider optical flow with displacements of only a few pixels per frame. This approach limits the applications to slower motions and fails to seriously address the issue of motion blur. Moreover they work on images that are considered to be taken with infinitely small exposure time, more or less in a "stop and shoot" approach, which limits the real time applications. Also most of these algorithms work on a series of images by calculating the displacement of every pixel from image to image, ignoring any information about motion that exists within each single image.
In this work we approach the problem of visual motion estimation from a different point of view. We have developed an algorithm that is based on interpreting the motion blur to estimate the optical flow field in a single image. The algorithm works in the spatial frequency domain, using all the information that can be gathered from a patch of the image. The first step is to obtain the logarithm of the spectrum, by applying the Fast Fourier Transform (FFT) on the image patch. It is recognizable on the result an ellipse centered on the origin with orientation perpendicular to the orientation of the velocity vector. In order to exctract this orientation we apply a steerable second Gaussian derivative filter. To compute the magnitude of the velocity vector, which is one dimensional we need only a 1D signal. Noise patterns make it difficult to estimate this magnitude from the 2D log spectrum. Therefore we collapse the 2D logarithm of the spectrum along the orientation of the velocity vector, transfering from two dimensions to one. The next step is to take the Cepstrum, by applying the FFT to this one dimensional signal. The Cepstrum is useful in extracting the magnitude of the velocity vector because the central ellipse in the 2D spectrum is echoed along the direction of the velocity vectors with a period equivalent to the magnitude of the velocity vector. This is obvious in the Cepstrum by the appearence of a negative peak at the value of the magnitude of the velocity vector. The computational complexity of the algorithm is bounded by the FFT which is The computational complexity of the algorithm is bounded by the FFT which is O(n \log n) where n the number of pixels in the image
Perivascular astrocytes and endothelium in the development of the blood- brain barrier in the optic tectum of the chick embryo
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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