1,721,065 research outputs found
Image Analysis and Rule-Based Reasoning for a Traffic Monitoring
No full textThe paper presents an approach for detecting vehicles in urban traffic scenes by means of rule-based reasoning on visual data. The strength of the approach is its formal separation between the low-level image processing modules (used for extracting visual data under various illumination conditions) and the high-level module, which provides a general-purpose knowledge-based framework for tracking vehicles in the scene. The image-processing modules extract visual data from the scene by spatio-temporal analysis during daytime, and by morphological analysis of headlights at night, The high-level module is designed as a forward chaining production rule system, working on symbolic data, i.e., vehicles and their attributes (area, pattern, direction, and others) and exploiting a set of heuristic rules tuned to urban traffic conditions, The synergy between the artificial intelligence techniques of the high-level and the low-level image analysis techniques provides the system with flexibility and robustness
Computational models for image processing for shared-memory multiprocessors
No full textDifferent tasks in image processing exhibit different computational requirements that should be considered with respect to the architecture. This is particularly critical in parallel machines where many parallelization techniques, as data partitioning and mapping on processors, use of shared memory space, exploitation of pipelining with pre-fetching affect dramatically the performance with a strong relation with algorithm and architectural parameters.The paper defines computational models for tightly-coupled multiprocessors with crossbar architecture, both for data-parallel local algorithms and for global algorithms such as spatial transformations. To solve the intrinsic memory limitations of low-cost, highly integrated systems, the paper proposes to extend the classical block processing model by analytically modeling also the case of multiple processing stages.The models have been compared in detail and have been efficiently adopted for optimizing performance in block processing on crossbar multiprocessors for low-level computer vision applications
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Improving data prefetching efficacy in multimedia applications
No full textThe workload of multimedia applications has a strong impact on cache memory performance, since the locality of memory references embedded in multimedia programs diers from that of traditional programs. In many cases, standard cache memory organization achieves poorer performance when used for multimedia. A widely-explored approach to improve cache performance is hardware prefetching, which allows the pre-loading of data in the cache before they are referenced. However, existing hardware prefetching approaches unable to exploit the potential improvement in performance, since they are not tailored to multimedia locality. In this paper we propose novel effective approaches to hardware prefetching to be used in image processing programs for multimedia. Experimental results (both on efficiency and on efficacy of the proposed approach) are reported for a suite of multimedia image processing programs including MPEG-2 decoding and encoding, convolution, thresholding, and edge chain coding
3D Object Recognition by VC-graphs and Interactive Constraint Satisfaction
No full textWe propose a novel approach for recognizing 3D CADmade objects in complex range images containing several overlapped and different objects. Objects are modeled by a graph whose nodes are surfaces and arcs are surface relations. We propose an object-centered graph model, called Visual Constraint graph (VC-graph), with special visual constraints modeling occlusions between object surfaces. The VC-graph is used for recognizing objects from each possible point of view, instead of evaluating many different single-view graphs. The reasoning engine is based on an original extension of the Constraint Satisfaction Problem (CSP) paradigm, called Interactive CSP (ICSP). CSP requires the acquisition of all surfaces before starting constraint propagation; instead, ICSP guides the acquisition of new surfaces only on-demand, without computing useless information and focussing attention only on significant image parts
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