1,720,975 research outputs found
Abstract Two motion-blurred images are better than one
No full textMotion blur is a smearing of the image due to a long aperture time. We show that when two motion-blurred images are available, having different blur directions, image restoration can be improved substantially. In particular, the direction of the motion blur and the PSF (Point Spread Function) of the blur can be computed robustly. Ó 2004 Published by Elsevier B.V. Keywords: Motion-blur;Blind deconvolution;Image deblurring;Multi-image restoration In memorium This paper is dedicated to Prof. Azriel Rosenfeld, my Ph.D. advisor, to whom I owe my academic career, for better or worse. In spite of the time that has passed since my graduation, I often ask myself how Azriel would do the tasks I am facing. In particular, in my most important duty as an advisor to my students, I try to be as helpful and dedicated to them as Azriel was to me. Co-chairing the 12th ICPR in 1994 was no different, and I tried to do the job as efficiently as Azriel would have done it. And since Azriel liked to write his papers * Corresponding author
Making a long video short: Dynamic video synopsis
No full textThe power of video over still images is the ability to represent dynamic activities. But video browsing and retrieval are inconvenient due to inherent spatio-temporal redundancies, where some time intervals may have no activity, or have activities that occur in a small image region. Video synopsis aims to provide a compact video representation, while preserving the essential activities of the original video. We present dynamic video synopsis, where most of the activity in the video is condensed by simultaneously showing several actions, even when they originally occurred at different times. For example, we can create a ”stroboscopic movie”, where multiple dynamic instances of a moving object are played simultaneously. This is an extension of the still stroboscopic picture. Previous approaches for video abstraction addressed mostly the temporal redundancy by selecting representative key-frames or time intervals. In dynamic video synopsis the activity is shifted into a significantly shorter period, in which the activity is much denser. Video examples can be found online i
Online registration of dynamic scenes using video extrapolation
No full textAn online process is proposed for video registration of dynamic scenes, such as scenes with dynamic textures or with moving objects. This process has three steps: (i) A few frames are assumed to be already registered. (ii) Using the registered frames, the next new frame is extrapolated. (iii) The actual new frame is registered to the extrapolated frame. Video extrapolation overcomes the bias introduced by dynamics in the scene, even when the dynamic regions cover almost the entire image. It can also overcome not only motion, but also many fluctuations in intensity. The traditional “brightness constancy ” is now replaced with “dynamics constancy”.
Online video registration of dynamic scenes using frame prediction
No full textAbstract. An online approach is proposed for Video registration of dynamic scenes, such as scenes with dynamic textures, moving objects, motion parallax, etc. This approach has three steps: (i) Assume that a few frames are already registered. (ii) Using the registered frames, the next frame is predicted. (iii) A new video frame is registered to the predicted frame. Frame prediction overcomes the bias introduced by dynamics in the scene, even when dynamic objects cover the majority of the image. It can also overcome many systematic changes in intensity, and the “brightness constancy ” is replaced with “dynamic constancy”. This predictive online approach can also be used with motion parallax, where non uniform image motion is caused by camera translation in a 3D scene with large depth variations. In this case a method to compute the camera ego motion is described.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
- …
