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Author | Anjan Dutta; Josep Llados; Horst Bunke; Umapada Pal | ||||
Title | A Product graph based method for dual subgraph matching applied to symbol spotting | Type | Conference Article | ||
Year | 2013 | Publication | 10th IAPR International Workshop on Graphics Recognition | Abbreviated Journal | |
Volume | Issue | Pages | |||
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Abstract | Product graph has been shown to be an efficient way for matching subgraphs. This paper reports the extension of the product graph methodology for subgraph matching applied to symbol spotting in graphical documents. This paper focuses on the two major limitations of the previous version of product graph: (1) Spurious nodes and edges in the graph representation and (2) Inefficient node and edge attributes. To deal with noisy information of vectorized graphical documents, we consider a dual graph representation on the original graph representing the graphical information and the product graph is computed between the dual graphs of the query graphs and the input graph.
The dual graph with redundant edges is helpful for efficient and tolerating encoding of the structural information of the graphical documents. The adjacency matrix of the product graph locates similar path information of two graphs and exponentiating the adjacency matrix finds similar paths of greater lengths. Nodes joining similar paths between two graphs are found by combining different exponentials of adjacency matrices. An experimental investigation reveals that the recall obtained by this approach is quite encouraging. |
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Address | Bethlehem; PA; USA; August 2013 | ||||
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ISSN | ISBN | Medium | |||
Area | Expedition | Conference | GREC | ||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ DLB2013b | Serial | 2359 | ||
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Author | Bhaskar Chakraborty; Andrew Bagdanov; Jordi Gonzalez; Xavier Roca | ||||
Title | Human Action Recognition Using an Ensemble of Body-Part Detectors | Type | Journal Article | ||
Year | 2013 | Publication | Expert Systems | Abbreviated Journal | EXSY |
Volume | 30 | Issue | 2 | Pages | 101-114 |
Keywords | Human action recognition;body-part detection;hidden Markov model | ||||
Abstract | This paper describes an approach to human action recognition based on a probabilistic optimization model of body parts using hidden Markov model (HMM). Our method is able to distinguish between similar actions by only considering the body parts having major contribution to the actions, for example, legs for walking, jogging and running; arms for boxing, waving and clapping. We apply HMMs to model the stochastic movement of the body parts for action recognition. The HMM construction uses an ensemble of body-part detectors, followed by grouping of part detections, to perform human identification. Three example-based body-part detectors are trained to detect three components of the human body: the head, legs and arms. These detectors cope with viewpoint changes and self-occlusions through the use of ten sub-classifiers that detect body parts over a specific range of viewpoints. Each sub-classifier is a support vector machine trained on features selected for the discriminative power for each particular part/viewpoint combination. Grouping of these detections is performed using a simple geometric constraint model that yields a viewpoint-invariant human detector. We test our approach on three publicly available action datasets: the KTH dataset, Weizmann dataset and HumanEva dataset. Our results illustrate that with a simple and compact representation we can achieve robust recognition of human actions comparable to the most complex, state-of-the-art methods. | ||||
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Notes | ISE | Approved | no | ||
Call Number | Admin @ si @ CBG2013 | Serial | 1809 | ||
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Author | Bhaskar Chakraborty; Michael Holte; Thomas B. Moeslund; Jordi Gonzalez; Xavier Roca | ||||
Title | A Selective Spatio-Temporal Interest Point Detector for Human Action Recognition in Complex Scenes | Type | Conference Article | ||
Year | 2011 | Publication | 13th IEEE International Conference on Computer Vision | Abbreviated Journal | |
Volume | Issue | Pages | 1776-1783 | ||
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Abstract | Recent progress in the field of human action recognition points towards the use of Spatio-Temporal Interest Points (STIPs) for local descriptor-based recognition strategies. In this paper we present a new approach for STIP detection by applying surround suppression combined with local and temporal constraints. Our method is significantly different from existing STIP detectors and improves the performance by detecting more repeatable, stable and distinctive STIPs for human actors, while suppressing unwanted background STIPs. For action representation we use a bag-of-visual words (BoV) model of local N-jet features to build a vocabulary of visual-words. To this end, we introduce a novel vocabulary building strategy by combining spatial pyramid and vocabulary compression techniques, resulting in improved performance and efficiency. Action class specific Support Vector Machine (SVM) classifiers are trained for categorization of human actions. A comprehensive set of experiments on existing benchmark datasets, and more challenging datasets of complex scenes, validate our approach and show state-of-the-art performance. | ||||
Address | Barcelona | ||||
Corporate Author | Thesis | ||||
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Language | Summary Language | Original Title | |||
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ISSN | 1550-5499 | ISBN | 978-1-4577-1101-5 | Medium | |
Area | Expedition | Conference | ICCV | ||
Notes | ISE | Approved | no | ||
Call Number | Admin @ si @ CHM2011 | Serial | 1811 | ||
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Author | Wenjuan Gong; Jürgen Brauer; Michael Arens; Jordi Gonzalez | ||||
Title | Modeling vs. Learning Approaches for Monocular 3D Human Pose Estimation | Type | Conference Article | ||
Year | 2011 | Publication | 1st IEEE International Workshop on Performance Evaluation on Recognition of Human Actions and Pose Estimation Methods | Abbreviated Journal | |
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Address | London, United Kingdom | ||||
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Area | Expedition | Conference | PERHAPS | ||
Notes | ISE | Approved | no | ||
Call Number | Admin @ si @ GBA2011 | Serial | 1812 | ||
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Author | Jordi Gonzalez; Josep M. Gonfaus; Carles Fernandez; Xavier Roca | ||||
Title | Exploiting Natural-Language Interaction in Video Surveillance Systems | Type | Conference Article | ||
Year | 2011 | Publication | V&L Net Workshop on Vision and Language | Abbreviated Journal | |
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Address | Brighton, UK | ||||
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ISSN | ISBN | Medium | |||
Area | Expedition | Conference | VL | ||
Notes | ISE | Approved | no | ||
Call Number | Admin @ si @ GGF2011 | Serial | 1813 | ||
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Author | Albert Gordo; Florent Perronnin | ||||
Title | Asymmetric Distances for Binary Embeddings | Type | Conference Article | ||
Year | 2011 | Publication | IEEE Conference on Computer Vision and Pattern Recognition | Abbreviated Journal | |
Volume | Issue | Pages | 729 - 736 | ||
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Abstract | In large-scale query-by-example retrieval, embedding image signatures in a binary space offers two benefits: data compression and search efficiency. While most embedding algorithms binarize both query and database signatures, it has been noted that this is not strictly a requirement. Indeed, asymmetric schemes which binarize the database signatures but not the query still enjoy the same two benefits but may provide superior accuracy. In this work, we propose two general asymmetric distances which are applicable to a wide variety of embedding techniques including Locality Sensitive Hashing (LSH), Locality Sensitive Binary Codes (LSBC), Spectral Hashing (SH) and Semi-Supervised Hashing (SSH). We experiment on four public benchmarks containing up to 1M images and show that the proposed asymmetric distances consistently lead to large improvements over the symmetric Hamming distance for all binary embedding techniques. We also propose a novel simple binary embedding technique – PCA Embedding (PCAE) – which is shown to yield competitive results with respect to more complex algorithms such as SH and SSH. | ||||
Address | Providence, RI | ||||
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ISSN | ISBN | 978-1-4577-0394-2 | Medium | ||
Area | Expedition | Conference | CVPR | ||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ GoP2011; IAM @ iam @ GoP2011 | Serial | 1817 | ||
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Author | Chenyang Fu; Kaida Xiao; Dimosthenis Karatzas; Sophie Wuerger | ||||
Title | Investigation of Unique Hue Setting Changes with Ageing | Type | Journal Article | ||
Year | 2011 | Publication | Chinese Optics Letters | Abbreviated Journal | COL |
Volume | 9 | Issue | 5 | Pages | 053301-1-5 |
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Abstract | Clromatic sensitivity along the protan, deutan, and tritan lines and the loci of the unique hues (red, green, yellow, blue) for a very large sample (n = 185) of colour-normal observers ranging from 18 to 75 years of age are assessed. Visual judgments are obtained under normal viewing conditions using colour patches on self-luminous display under controlled adaptation conditions. Trivector discrimination thresholds show an increase as a function of age along the protan, deutan, and tritan axes, with the largest increase present along the tritan line, less pronounced shifts in unique hue settings are also observed. Based on the chromatic (protan, deutan, tritan) thresholds and using scaled cone signals, we predict the unique hue changes with ageing. A dependency on age for unique red and unique yellow for predicted hue angle is found. We conclude that the chromatic sensitivity deteriorates significantly with age, whereas the appearance of unique hues is much less affected, remaining almost constant despite the known changes in the ocular media. | ||||
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Area | Expedition | Conference | |||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ XFW2011 | Serial | 1818 | ||
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Author | Lluis Pere de las Heras; Joan Mas; Gemma Sanchez; Ernest Valveny | ||||
Title | Descriptor-based Svm Wall Detector | Type | Conference Article | ||
Year | 2011 | Publication | 9th International Workshop on Graphic Recognition | Abbreviated Journal | |
Volume | Issue | Pages | |||
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Abstract | Architectural floorplans exhibit a large variability in notation. Therefore, segmenting and identifying the elements of any kind of plan becomes a challenging task for approaches based on grouping structural primitives obtained by vectorization. Recently, a patch-based segmentation method working at pixel level and relying on the construction of a visual vocabulary has been proposed showing its adaptability to different notations by automatically learning the visual appearance of the elements in each different notation. In this paper we describe an evolution of this new approach in two directions: firstly we evaluate different features to obtain the description of every patch. Secondly, we train an SVM classifier to obtain the category of every patch instead of constructing a visual vocabulary. These modifications of the method have been tested for wall detection on two datasets of architectural floorplans with different notations and compared with the results obtained with the original approach. | ||||
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Area | Expedition | Conference | GREC | ||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ HMS2011b | Serial | 1819 | ||
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Author | Marçal Rusiñol; V. Poulain d'Andecy; Dimosthenis Karatzas; Josep Llados | ||||
Title | Classification of Administrative Document Images by Logo Identification | Type | Conference Article | ||
Year | 2011 | Publication | In proceedings of 9th IAPR Workshop on Graphic Recognition | Abbreviated Journal | |
Volume | Issue | Pages | |||
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Abstract | This paper is focused on the categorization of administrative document images (such as invoices) based on the recognition of the supplier's graphical logo. Two different methods are proposed, the first one uses a bag-of-visual-words model whereas the second one tries to locate logo images described by the blurred shape model descriptor within documents by a sliding-window technique. Preliminar results are reported with a dataset of real administrative documents. | ||||
Address | Seoul, Corea | ||||
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Area | Expedition | Conference | GREC | ||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ RPK2011 | Serial | 1821 | ||
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Author | Kaida Xiao; Chenyang Fu; D.Mylonas; Dimosthenis Karatzas; S. Wuerger | ||||
Title | Unique Hue Data for Colour Appearance Models. Part ii: Chromatic Adaptation Transform | Type | Journal Article | ||
Year | 2013 | Publication | Color Research & Application | Abbreviated Journal | CRA |
Volume | 38 | Issue | 1 | Pages | 22-29 |
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Abstract | Unique hue settings of 185 observers under three room-lighting conditions were used to evaluate the accuracy of full and mixed chromatic adaptation transform models of CIECAM02 in terms of unique hue reproduction. Perceptual hue shifts in CIECAM02 were evaluated for both models with no clear difference using the current Commission Internationale de l'Éclairage (CIE) recommendation for mixed chromatic adaptation ratio. Using our large dataset of unique hue data as a benchmark, an optimised parameter is proposed for chromatic adaptation under mixed illumination conditions that produces more accurate results in unique hue reproduction. © 2011 Wiley Periodicals, Inc. Col Res Appl, 2013 | ||||
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Area | Expedition | Conference | |||
Notes | DAG | Approved | no | ||
Call Number | Admin @ si @ XFM2013 | Serial | 1822 | ||
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Author | Sophie Wuerger; Kaida Xiao; Chenyang Fu; Dimosthenis Karatzas | ||||
Title | Colour-opponent mechanisms are not affected by age-related chromatic sensitivity changes | Type | Journal Article | ||
Year | 2010 | Publication | Ophthalmic and Physiological Optics | Abbreviated Journal | OPO |
Volume | 30 | Issue | 5 | Pages | 635-659 |
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Abstract | The purpose of this study was to assess whether age-related chromatic sensitivity changes are associated with corresponding changes in hue perception in a large sample of colour-normal observers over a wide age range (n = 185; age range: 18-75 years). In these observers we determined both the sensitivity along the protan, deutan and tritan line; and settings for the four unique hues, from which the characteristics of the higher-order colour mechanisms can be derived. We found a significant decrease in chromatic sensitivity due to ageing, in particular along the tritan line. From the unique hue settings we derived the cone weightings associated with the colour mechanisms that are at equilibrium for the four unique hues. We found that the relative cone weightings (w(L) /w(M) and w(L) /w(S)) associated with the unique hues were independent of age. Our results are consistent with previous findings that the unique hues are rather constant with age while chromatic sensitivity declines. They also provide evidence in favour of the hypothesis that higher-order colour mechanisms are equipped with flexible cone weightings, as opposed to fixed weights. The mechanism underlying this compensation is still poorly understood. | ||||
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Notes | DAG; IF: 1.259 | Approved | no | ||
Call Number | Admin @ si @ WXF2010 | Serial | 1826 | ||
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Author | Susana Alvarez; Anna Salvatella; Maria Vanrell; Xavier Otazu | ||||
Title | Low-dimensional and Comprehensive Color Texture Description | Type | Journal Article | ||
Year | 2012 | Publication | Computer Vision and Image Understanding | Abbreviated Journal | CVIU |
Volume | 116 | Issue | I | Pages | 54-67 |
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Abstract | Image retrieval can be dealt by combining standard descriptors, such as those of MPEG-7, which are defined independently for each visual cue (e.g. SCD or CLD for Color, HTD for texture or EHD for edges).
A common problem is to combine similarities coming from descriptors representing different concepts in different spaces. In this paper we propose a color texture description that bypasses this problem from its inherent definition. It is based on a low dimensional space with 6 perceptual axes. Texture is described in a 3D space derived from a direct implementation of the original Julesz’s Texton theory and color is described in a 3D perceptual space. This early fusion through the blob concept in these two bounded spaces avoids the problem and allows us to derive a sparse color-texture descriptor that achieves similar performance compared to MPEG-7 in image retrieval. Moreover, our descriptor presents comprehensive qualities since it can also be applied either in segmentation or browsing: (a) a dense image representation is defined from the descriptor showing a reasonable performance in locating texture patterns included in complex images; and (b) a vocabulary of basic terms is derived to build an intermediate level descriptor in natural language improving browsing by bridging semantic gap |
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ISSN | 1077-3142 | ISBN | Medium | ||
Area | Expedition | Conference | |||
Notes | CAT;CIC | Approved | no | ||
Call Number | Admin @ si @ ASV2012 | Serial | 1827 | ||
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Author | Miquel Ferrer; Dimosthenis Karatzas; Ernest Valveny; I. Bardaji; Horst Bunke | ||||
Title | A Generic Framework for Median Graph Computation based on a Recursive Embedding Approach | Type | Journal Article | ||
Year | 2011 | Publication | Computer Vision and Image Understanding | Abbreviated Journal | CVIU |
Volume | 115 | Issue | 7 | Pages | 919-928 |
Keywords | Median Graph, Graph Embedding, Graph Matching, Structural Pattern Recognition | ||||
Abstract | The median graph has been shown to be a good choice to obtain a represen- tative of a set of graphs. However, its computation is a complex problem. Recently, graph embedding into vector spaces has been proposed to obtain approximations of the median graph. The problem with such an approach is how to go from a point in the vector space back to a graph in the graph space. The main contribution of this paper is the generalization of this previ- ous method, proposing a generic recursive procedure that permits to recover the graph corresponding to a point in the vector space, introducing only the amount of approximation inherent to the use of graph matching algorithms. In order to evaluate the proposed method, we compare it with the set me- dian and with the other state-of-the-art embedding-based methods for the median graph computation. The experiments are carried out using four dif- ferent databases (one semi-artificial and three containing real-world data). Results show that with the proposed approach we can obtain better medi- ans, in terms of the sum of distances to the training graphs, than with the previous existing methods. | ||||
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Notes | DAG | Approved | no | ||
Call Number | IAM @ iam @ FKV2011 | Serial | 1831 | ||
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Author | Mohammad Rouhani; Angel Sappa | ||||
Title | Correspondence Free Registration through a Point-to-Model Distance Minimization | Type | Conference Article | ||
Year | 2011 | Publication | 13th IEEE International Conference on Computer Vision | Abbreviated Journal | |
Volume | Issue | Pages | 2150-2157 | ||
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Abstract | This paper presents a novel formulation, which derives in a smooth minimization problem, to tackle the rigid registration between a given point set and a model set. Unlike most of the existing works, which are based on minimizing a point-wise correspondence term, we propose to describe the model set by means of an implicit representation. It allows a new definition of the registration error, which works beyond the point level representation. Moreover, it could be used in a gradient-based optimization framework. The proposed approach consists of two stages. Firstly, a novel formulation is proposed that relates the registration parameters with the distance between the model and data set. Secondly, the registration parameters are obtained by means of the Levengberg-Marquardt algorithm. Experimental results and comparisons with state of the art show the validity of the proposed framework. | ||||
Address | Barcelona | ||||
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ISSN | 1550-5499 | ISBN | 978-1-4577-1101-5 | Medium | |
Area | Expedition | Conference | ICCV | ||
Notes | ADAS | Approved | no | ||
Call Number | Admin @ si @ RoS2011b; ADAS @ adas @ | Serial | 1832 | ||
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Author | Fadi Dornaika; Jose Manuel Alvarez; Angel Sappa; Antonio Lopez | ||||
Title | A New Framework for Stereo Sensor Pose through Road Segmentation and Registration | Type | Journal Article | ||
Year | 2011 | Publication | IEEE Transactions on Intelligent Transportation Systems | Abbreviated Journal | TITS |
Volume | 12 | Issue | 4 | Pages | 954-966 |
Keywords | road detection | ||||
Abstract | This paper proposes a new framework for real-time estimation of the onboard stereo head's position and orientation relative to the road surface, which is required for any advanced driver-assistance application. This framework can be used with all road types: highways, urban, etc. Unlike existing works that rely on feature extraction in either the image domain or 3-D space, we propose a framework that directly estimates the unknown parameters from the stream of stereo pairs' brightness. The proposed approach consists of two stages that are invoked for every stereo frame. The first stage segments the road region in one monocular view. The second stage estimates the camera pose using a featureless registration between the segmented monocular road region and the other view in the stereo pair. This paper has two main contributions. The first contribution combines a road segmentation algorithm with a registration technique to estimate the online stereo camera pose. The second contribution solves the registration using a featureless method, which is carried out using two different optimization techniques: 1) the differential evolution algorithm and 2) the Levenberg-Marquardt (LM) algorithm. We provide experiments and evaluations of performance. The results presented show the validity of our proposed framework. | ||||
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ISSN | 1524-9050 | ISBN | Medium | ||
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Notes | ADAS | Approved | no | ||
Call Number | Admin @ si @ DAS2011; ADAS @ adas @ das2011a | Serial | 1833 | ||
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